Deletion Of Site Research Articles

STEAP3 promotes colon cancer cell proliferation and migration via regulating histone acetylation.

Colorectal cancer (CRC) is the third most prevalent diagnosed cancer in men and second most prevalent cancer in women. H3K27ac alterations are more commonly than gene mutations in colorectal cancer. Most colorectal cancer genes have significant H3K27ac changes, which leads to an over-expression disorder in gene transcription. Over-expression of STEAP3 is involved in a variety of tumors, participating in the regulation of cancer cell proliferation and migration. The purpose of this work is to investigate the role of STEAP3 in the regulation of histone modification (H3K27ac) expression in colon cancer. Bioinformatic ChIP-seq, ChIP-qPCR and ATAC-seq were used to analyze the histone modification properties and gene accessibility of STEAP3. Western blot and qRT-PCR were used to evaluate relative protein and gene expression, respectively. CRISPR/Cas9 technology was used to knockout STEAP3 on colon cancer cells to analyze the effect of ATF3 on STEAP3. STEAP3 was over-expressed in colon cancer and associated with higher metastases and more invasive and worse stage of colon cancer. ChIP-seq and ChIP-qPCR analyses revealed significant enrichment of H3K27ac in the STEAP3 gene. In addition, knocking down STEAP3 significantly inhibits colon cancer cell proliferation and migration and down-regulates H3K27ac expression. ChIP-seq found that ATF3 is enriched in the STEAP3 gene and CRISPR/Cas9 technology used for the deletion of the ATF3 binding site suppresses the expression of STEAP3. Over-expression of STEAP3 promotes colon cancer cell proliferation and migration. Mechanical studies have indicated that H3K27ac and ATF3 are significantly enriched in the STEAP3 gene and regulate the over-expression of STEAP3.

Data from the Indian drug regulator and from Clinical Trials Registry-India does not always match.

In India, regulatory trials, which require the drug regulator's permission, must be registered with the Clinical Trials Registry-India (CTRI) as of 19 March 2019. In this study, for about 300 trials, we aimed to identify the CTRI record that matched the trial for which the regulator had given permission. After identifying 'true pairs', our goal was to determine whether the sites and Principal Investigators mentioned in the permission letter were the same as those mentioned in the CTRI record. We developed a methodology to compare the regulator's permission letters with CTRI records. We manually validated 151 true pairs by comparing the titles, the drug interventions, and the indications. We then examined discrepancies in their trial sites and Principal Investigators. Our findings revealed substantial variations in the number and identity of sites and Principal Investigators between the permission letters and the CTRI records. These discrepancies raise concerns about the accuracy and transparency of regulatory trials in India. We recommend easier data extraction from regulatory documents, cross-referencing regulatory documents and CTRI records, making public the changes to approval letters, and enforcing oversight by Institutional Ethics Committees for site additions or deletions. These steps will increase transparency around regulatory trials running in India.

Tracing the Maternal Line in Glacial–Interglacial Migrations of Populus tremuloides: Finding Trees for Future Sustainable Forests by Searching in the Past

Maintaining and planting sustainable forests is fundamental in perpetuating the essential functions of these ecosystems. A central aspect of managing forests for future resilience is the consideration of past migration and evolution of trees using genetic and genomic data to ensure that functionally appropriate diversity is conserved and utilized. In our study, we generated and compared genetic and genomic data from the plastome to better understand phylogeography and molecular evolution in the tree species Populus tremuloides (aspen). With these analyses, we found evidence of divergence and migration between northern and southern sites. Additionally, evidence of deep incomplete plastome sorting across the Salicaceae was found when examining insertion–deletion (indel) sites associated with DNA repair. By examining these indels in plastomic genes with introns across Salicaceae, we found a strong correlation between the abundance of DNA repair with genomic position and transcript abundance. From our findings, we conclude that previously ignored plastomic data are essential in understanding phylogeography and the evolution of key metabolic processes for improved aspen forest planning. Given the propensity of aspen forests to host high levels of biodiversity, rapidly sequester carbon, absorb excess nitrogen, and efficiently regulate snowmelt, improvements to planning and conservation will be highly impactful.

Calcitriol ameliorates motor deficits and prolongs survival of Chrne-deficient mouse, a model for congenital myasthenic syndrome, by inducing Rspo2

Signal transduction at the neuromuscular junction (NMJ) is compromised in a diverse array of diseases including congenital myasthenic syndromes (CMS). Germline mutations in CHRNE encoding the acetylcholine receptor (AChR) ε subunit are the most common cause of CMS. An active form of vitamin D, calcitriol, binds to vitamin D receptor (VDR) and regulates gene expressions. We found that calcitriol enhanced MuSK phosphorylation, AChR clustering, and myotube twitching in co-cultured C2C12 myotubes and NSC34 motor neurons. RNA-seq analysis of co-cultured cells showed that calcitriol increased the expressions of Rspo2, Rapsn, and Dusp6. ChIP-seq of VDR revealed that VDR binds to a region approximately 15 ​kbp upstream to Rspo2. Biallelic deletion of the VDR-binding site of Rspo2 by CRISPR/Cas9 in C2C12 myoblasts/myotubes nullified the calcitriol-mediated induction of Rspo2 expression and MuSK phosphorylation. We generated Chrne knockout (Chrne KO) mouse by CRISPR/Cas9. Intraperitoneal administration of calcitriol markedly increased the number of AChR clusters, as well as the area, the intensity, and the number of synaptophysin-positive synaptic vesicles, in Chrne KO mice. In addition, calcitriol ameliorated motor deficits and prolonged survival of Chrne KO mice. In the skeletal muscle, calcitriol increased the gene expressions of Rspo2, Rapsn, and Dusp6. We propose that calcitriol is a potential therapeutic agent for CMS and other diseases with defective neuromuscular signal transmission.

STAT3 and SOX-5 induce BRG1-mediated chromatin remodeling of RORCE2 in Th17 cells

Retinoid-related orphan receptor gamma t (RORγt) is the lineage-specific transcription factor for T helper 17 (Th17) cells. Our previous study demonstrated that STAT3 likely participates in the activation of RORCE2 (a novel enhancer of the RORγt gene) in Th17 cells. However, the detailed mechanism is still unclear. Here, we demonstrate that both STAT3 and SOX-5 mediate the enhancer activity of RORCE2 in vitro. Deletion of the STAT3 binding site (STAT3-BS) in RORCE2 impaired RORγt expression and Th17 differentiation, resulting in reduced severity of experimental autoimmune encephalomyelitis (EAE). Mechanistically, STAT3 and SOX-5 bind the RORCE2 region and recruit the chromatin remodeling factor BRG1 to remodel the nucleosomes positioned at this region. Collectively, our data suggest that STAT3 and SOX-5 mediate the differentiation of Th17 cells through the induction of BRG1-mediated chromatin remodeling of RORCE2 in Th17 cells.

Dynamic Connectivity in Disk Graphs

Let S subseteq mathbb {R}^2 be a set of nsites in the plane, so that every site s in S has an associated radiusr_s > 0. Let mathcal {D}(S) be the disk intersection graph defined by S, i.e., the graph with vertex set S and an edge between two distinct sites s, t in S if and only if the disks with centers s, t and radii r_s, r_t intersect. Our goal is to design data structures that maintain the connectivity structure of mathcal {D}(S) as sites are inserted and/or deleted in S. First, we consider unit disk graphs, i.e., we fix r_s = 1, for all sites s in S. For this case, we describe a data structure that has O(log ^2 n) amortized update time and O(log n/log log n) query time. Second, we look at disk graphs with bounded radius ratioPsi , i.e., for all s in S, we have 1 le r_s le Psi , for a parameter Psi that is known in advance. Here, we not only investigate the fully dynamic case, but also the incremental and the decremental scenario, where only insertions or only deletions of sites are allowed. In the fully dynamic case, we achieve amortized expected update time O(Psi log ^{4} n) and query time O(log n/log log n). This improves the currently best update time by a factor of Psi . In the incremental case, we achieve logarithmic dependency on Psi , with a data structure that has O(alpha (n)) amortized query time and O(log Psi log ^{4} n) amortized expected update time, where alpha (n) denotes the inverse Ackermann function. For the decremental setting, we first develop an efficient decremental disk revealing data structure: given two sets R and B of disks in the plane, we can delete disks from B, and upon each deletion, we receive a list of all disks in R that no longer intersect the union of B. Using this data structure, we get decremental data structures with a query time of O(log n/log log n) that supports deletions in O(nlog Psi log ^{4} n) overall expected time for disk graphs with bounded radius ratio Psi and O(nlog ^{5} n) overall expected time for disk graphs with arbitrary radii, assuming that the deletion sequence is oblivious of the internal random choices of the data structures.

In vitro synthesis and biochemical characterization of acyl-homoserine lactone synthase and its deletion mutant.

Quorum sensing can induce density-dependent gene expressions that cause various problems. For quorum-sensing inhibition, fundamental solutions such as gene manipulation are required, and acyl-homoserine lactone synthase (AHL synthase), which synthesizes the universal quorum-sensing signal of gram-negative bacteria, can be used as a target. In this study, researchers synthesized His-tagged AHL synthase and its deletion mutant that lacks the active site and compared their biochemical characteristics. His-YpeI, the 6x His-tagged AHL synthase of Serratia fonticola, and His-ΔYpeI, its deletion mutant, were designed, and their property conservation were examined using in silico projection tools. For in vitro synthesis of enzymes, the His-YpeI CFPS template was synthesized by in vitro gene synthesis, and the His-ΔYpeI CFPS template was obtained by deletion PCR. CFPS was performed and the products were purified with the 6x His-tag. The enzymes' properties were compared using an enzymatic assay. The bioinformatic analysis confirmed the conservation of biochemical properties between 6x His-tagged and untagged enzymes, including helix-turn-helix interactions, hydropathy profiles, and tertiary structure between His-YpeI and YpeI and between His-ΔYpeI and ΔYpeI. His-YpeI and His-ΔYpeI synthesized by CFPS were found to have the expected molecular weights and demonstrated distinct differences in enzyme activity. The analyzed enzymatic constants supported a significant decrease in substrate affinity and reaction rate as a result of YpeI's enzyme active site deletion. This result showed that CFPS could be used for in vitro protein synthesis, and quorum sensing could be inhibited at the enzymatic level due to the enzyme active site's deletion mutation.

The Emergence of Novel Variants of the Porcine Epidemic Diarrhea Virus Spike Gene from 2011 to 2023

The porcine epidemic diarrhea virus (PEDV) has caused severe economic losses in the pig industry. Since its discovery, the virus has spread in pig herds for more than 50 years. Many new features have been found in the PEDV spike genes. In this study, 123 representative S genes were used to analyze their characteristics across strains. Phylogenetic analysis revealed that PEDV can be divided into nine groups: G1a, G1b, G1c, G1d, G2a, G2b, G2c, G2d, and G3. In addition, 21 different lengths of the S gene were found. Analysis of the amino acid insertion and deletion sites revealed that most deletions and insertions occurred in the loops of the spike quaternary structure, primarily in the D0 and N‐terminal domains (NTDs). According to the above results, PEDV has undergone considerable evolution, possibly under the immune pressure of vaccination. These results are highly important for understanding the current epidemic situation of PEDV.

Decoding Complexity in Synthetic Oligonucleotides: Unraveling Coeluting Isobaric Impurity Ions by High Resolution Mass Spectrometry.

Analyzing coeluting impurities with similar masses in synthetic oligonucleotides by liquid chromatography-mass spectrometry (LC-MS) poses challenges due to inadequate separation in either dimension. Herein, we present a direct method employing fully resolved isotopic envelopes, enabled by high resolution mass spectrometry (HRMS), to identify and quantify isobaric impurity ions resulting from the deletion or addition of a uracil (U) or cytosine (C) nucleotide from or to the full-length sequence. These impurities may each encompass multiple sequence variants arising from various deletion or addition sites. The method utilizes a full or targeted MS analysis to measure accurate isotopic distributions that are chemical formula dependent but nucleotide sequence independent. This characteristic enables the quantification of isobaric impurity ions involving sequence variants, a capability typically unavailable in sequence-dependent MS/MS methods. Notably, this approach does not rely on standard curves to determine isobaric impurity compositions in test samples; instead, it utilizes the individual isotopic distributions measured for each impurity standard. Moreover, in cases where specific impurity standards are unavailable, the measured isotopic distributions can be adequately replaced with the theoretical distributions (calculated based on chemical formulas of standards) adjusted using experiment-specific correction factors. In summary, this streamlined approach overcomes the limitations of LC-MS analysis for coeluting isobaric impurity ions, offering a promising solution for the in-depth profiling of complex impurity mixtures in synthetic oligonucleotide therapeutics.

Dissemination of Integron Class 1 among XDR isolates of P. aeruginosa in Najaf City

Background: Integrons are gene capture systems observed in chromosomes, plasmids, and transposons, where identified and capture multiple gene cassettes. Integerons are consists of 3 elements: the initial is integrase gene (int1) encoding integrase enzyme (int1), which is essential to insertion or deletion of specific site. The second element is attI as integron-connected recombination site. The 3rd element is promoter (Pc), which is required in the expression of cassette-connected genes. 
 Aim of the Study: This thesis designed to examine the occurrence of integron class one genes among XDR isolates of P. aeruginosa. 
 Methods: An overall of 79 specimens were isolated from patients during the period of study and the specimens were carried to the laboratory. By monoplex PCR assay, the 19 XDR isolates of P. aeruginosa were investigated for the presence of integrons class one using intI1primer. 
 Results: This result found that 8 isolates are isolated from burns, 7 isolates are from urine, 4 isolates are from wounds. The PCR results show that 17 (89.5%) of the isolates harbored integrase (intI1) gene, while two isolate (10.5%) was negative for intI1 gene. Conclusions: Present result showed elevated occurrence of integrons class one among XDR isolates of P.aeruginosa.

Suppression of KLF5 basal expression in oral carcinoma-derived cells through three intact CREB1-binding sites in the silencer region

ObjectivesKrüppel-like factor (KLF)5, which is overexpressed in carcinomas such as oral cancer, inhibits epidermal differentiation. KLF5 induces dedifferentiation of carcinoma cells, which effectuates carcinoma progression; nevertheless, the regulatory mechanism affecting the transcription of the KLF5 gene remains ambiguous. MethodsTranscriptional activity of the KLF5 silencer, specifically the 425-bp region (425-region), was examined using reporter assays. An additional analysis was conducted to assess the impact of the minimal essential region (MER) of KLF5 on its basal expression. The affinity of cAMP responsive element binding protein 1 (CREB1) for three potential CREB1-binding sites in the 425-region was analyzed using DNA pull-down and quantitative chromatin immunoprecipitation assays. Reporter assays employing a human oral squamous carcinoma cell line, HSC2, transfected with small interfering RNA or complementary DNA for CREB1, were performed to investigate the effect of CREB1 binding sites on MER activity. ResultsThe 425-region exhibited no transcriptional activity and suppressed MER transcriptional activity. This region encodes three putative CREB1-binding sites, and CREB1 demonstrated equal binding affinity for all three sites. The deletion of each of these binding sites reduced CREB1 precipitation and enhanced MER activity. Endogenous CREB1 knockdown and overexpression elevated and reduced MER activity, respectively, at the intact sites. Conversely, site deletion hampered and improved MER activity upon CREB1 knockdown and overexpression, respectively. ConclusionsSuppression of KLF5 basal expression via CREB1 binding to the 425-region requires all three CREB1-binding sites to remain intact in oral carcinoma cells. Consequently, deletion of the CREB1-binding site relieves suppression of KLF5 basal expression.

IGF2BP1/IMP1 Deletion Enhances a Facultative Stem Cell State via Regulation of MAP1LC3B

Background & AimsThe intestinal epithelium interfaces with a diverse milieu of luminal contents while maintaining robust digestive and barrier functions. Facultative intestinal stem cells are cells that survive tissue injury and divide to re-establish the epithelium. Prior studies demonstrate autophagic state as functional marker of facultative intestinal stem cells, but regulatory mechanisms are not known. The current study evaluated a post-transcriptional regulation of autophagy as an important factor for facultative stem cell state and tissue regeneration. MethodsWe evaluated stem cell composition, autophagic vesicle content, organoid formation, and in vivo regeneration in mice with intestinal epithelial deletion of the RNA binding protein IMP1. The contribution of autophagy to resulting in vitro and in vivo phenotypes was evaluated via genetic inactivation of Atg7. Molecular analyses of IMP1 modulation of autophagy at the protein and transcript localization levels were performed using IMP1 mutant studies and single molecule fluorescent in situ hybridization (smFISH). ResultsEpithelial Imp1 deletion reduced Lgr5+ cell frequency but enhanced both organoid formation efficiency and in vivo regeneration following irradiation. We confirmed prior studies demonstrating increased autophagy with IMP1 deletion. Deletion of Atg7 reversed the enhanced regeneration observed with Imp1 deletion. IMP1 deletion or mutation of IMP1 phosphorylation sites enhanced expression of essential autophagy protein Microtubule Associated Protein 1 Light Chain 3 Beta (MAP1LC3B). Furthermore, immunofluorescence imaging coupled with smFISH demonstrated IMP1 colocalization with MAP1LC3B transcripts at homeostasis. Stress induction led to decreased co-localization. ConclusionsDepletion of IMP1 enhances autophagy, which promotes intestinal regeneration via expansion of facultative intestinal stem cells.

Leukoencephalopathy with Brain stem and Spinal cord involvement and Lactate elevation (LBSL): Report of a new family and a novel DARS2 mutation

BackgroundLBSL is a mitochondrial disorder caused by mutations in the mitochondrial aspartyl-tRNA synthetase gene DARS2, resulting in a distinctive pattern on brain magnetic resonance imaging (MRI) and spectroscopy. Clinical presentation varies from severe infantile to chronic, slowly progressive neuronal deterioration in adolescents or adults. Most individuals with LBSL are compound heterozygous for one splicing defect in an intron 2 mutational hotspot and a second defect that could be a missense, non-sense, or splice site mutation or deletion resulting in decreased expression of the full-length protein. AimTo present a new family with two affected members with LBSL and report a novel DARS2 mutation. ResultsAn 8-year-old boy (Patient 1) was referred due to headaches and abnormal MRI, suggestive of LBSL. Genetic testing revealed a previously reported c.492 + 2 T > C mutation in the DARS2 gene. Sanger sequencing uncovered a novel variant c.228-17C > G in the intron 2 hotspot. Family studies found the same genetic changes in an asymptomatic 4-year-old younger brother (Patient 2), who was found on follow-up to have an abnormal MRI. mRNA extracted from patients' fibroblasts showed that the c.228-17C > G mutation caused skipping of exon 3 resulting in lower DARS2 mRNA level. Complete absence of DARS2 protein was also found in both patients. SummaryWe present a new family with two children affected with LBSL and describe a novel mutation in the DARS2 intron 2 hotspot. Despite findings of extensive white matter disease in the brain and spine, the proband in this family presented only with headaches, while the younger sibling, who also had extensive white matter changes, was asymptomatic. Our in-vitro results confirmed skipping of exon 3 in patients and family members carrying the intron 2 variant, which is consistent with previous reported mutations in intron 2 hotspots. DARS2 mRNA and protein levels were also reduced in both patients, further supporting the pathogenicity of the novel variant.

Abstract B075: Identifying functional allosteric binding sites using a systematic and scalable AMPS screening platform for drug discovery

Abstract Endogenous cellular metabolites have been shown to bind and regulate proteins involved in tumorigenesis. These low-affinity metabolite-protein interactions can modulate protein function through binding at allosteric sites. As an example, in normal cells, the ABL1 protein is regulated by N-terminal myristylation, which binds to a hydrophobic pocket in the C-terminal lobe of the kinase domain autoinhibiting its activity. Fusion of BCR to ABL1 leads to deletion of the N-terminal myristylation site activating BCR-ABL oncoprotein leading to chronic myeloid leukemia (CML). Similarly, autopalmitoylation of TEAD proteins regulates transcriptional output of Hippo signaling and tumorigenesis. Allosteric metabolite binding sites on these targets have been successfully used to generate new medicines (e.g.: Asciminib for BCR-ABL) and investigational cancer therapies (e.g.: IK-930, VT3989 for TEAD). However, there are limited approaches that can be broadly deployed to discover functional regulatory sites on precision oncology targets. Atavistik Bio has developed the AMPS (Atavistik Metabolite Protein Screening) platform that enables systematic and scalable screening of metabolites against proteins or protein complexes of interest. The AMPS platform technology integrates equilibrium dialysis with sensitive mass-spectrometry to screen a proprietary metabolite library. A state-of-the-art computational workflow coupled with deep mechanistic structure-function characterization enables us to discover novel functional allosteric modulators. To validate the platform, we have screened several precision oncology targets and characterized the AMPS metabolite hits with functional assays. For ABL1 tyrosine kinase, we have applied AMPS on distinct enzyme forms to probe the role of metabolite binding in the context of phosphorylation states and drug resistant T315I mutant forms. In addition, AMPS allows us to investigate novel metabolite sensitization of ABL1 in the presence of existing drugs Imatinib and Asciminib. Results from AMPS and follow up experiments highlight phosphorylation state dependency on myristate binding to ABL1. In conclusion, we demonstrate the AMPS platform can identify highly conserved allosteric protein-metabolite interactions to advance small molecule drug discovery efforts for new precision medicines. Citation Format: Anil K Padyana, Anna Schinzel, Gordon Murray, Joseph H LaPointe, Kaitlyn Selmer, Truc Pham, Melissa J Buskes, Shomit Sengupta, Maria-Jesus Blanco, Thomas Roddy, Marion Dorsch. Identifying functional allosteric binding sites using a systematic and scalable AMPS screening platform for drug discovery [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B075.

Cis-Acting Splicing-Associated Variants Can Redefine the Molecular Signature of Genes Commonly Mutated in Acute Myeloid Leukemia

Introduction: Acute Myeloid Leukemia (AML) is a blood malignancy that occurs as a result of genomic alterations acquired in hematopoietic stem cells (HSCs). Several studies have recognized the importance of these alterations, including chromosomal rearrangements and single nucleotide variations (SNVs), for the classification and risk stratification of patients. However, none of these studies have thoroughly explored the functional impact of these lesions, potentially leading to the oversight or misinterpretation of certain driver mutations. In this study, we focused on the splicing process, as we aim to comprehensively characterize cis-acting splicing-associated variants (SAVs) in a large cohort of AML patients. Methods: We obtained recurrent driver gene variants (n= 3,847) from Table S5 reported by Papaemmanuil et al. and selected unique SNVs (n= 915) for our analysis. Among them, 628 (69%) were missense variants, 232 (25%) were nonsense variants, and 55 (6%) were located within splice sites. To assess their potential impact on splicing, we employed three splicing predictor tools (MaxEntScan, regSNP-splicing, and SpliceAI) and considered variants with two favorable predictions for further functional studies. Firstly, we attempted to locate the SNVs within the exomes of the TCGA-LAML (n= 149) and the BeatAML (n=342) datasets available in the Genomic Data Commons repository. If an SNV was identified, we obtained the RNA sequencing bam file from the corresponding patient's sample and utilized the rest of the cohort as a control for statistical analysis (p<0.05 for significance). In cases where the SNV was not found in these datasets, we employed the pSPL3-based splicing reporter minigene assay to study the variant. Results: The predictors unanimously identified all 55 splice-site affecting variants as true positives and reclassified 20 missense and nonsense variants as likely SAVs. Functional validation experiments confirmed that 11 of these variants (55%) indeed had an impact on splicing. Analysis of RNA sequencing data revealed interesting findings in commonly observed AML hotspots. For instance, in cases of U2AF1 c.470A>G and IDH1 c.394C>A, novel donor splice sites were created at distances of one (p=0.04522) and 34 nucleotides from the mutations (p=0.01878), respectively. Whereas, the TP53 c.395A>G change was found to activate a cryptic acceptor splice site located XX nucleotides away (p=0). Among private AML variants, minigene assays showed that eight variants resulted in aberrant splicing compared to the wild-type. Three variants led to exon skipping due to the loss of canonical donor splice sites ( EZH2 c.363G>A, FLT3 c.2523C>A, and TET2 c.3500G>A), four variants caused the activation of a novel donor splice site ( PTPN11 c.1508G>T, WT1 c.1157C>A, STAG2 c.545T>G, and KDM6A c.1516C>T), and one variant resulted in both exon skipping and the creation of a donor splice site ( RAD21 c.688G>A). Consequently, the predicted impact on the protein varied, with FLT3 and TET2 variants potentially leading to an in-frame deletion of the ATP-binding site and TET2-oxygenase domain, respectively, with the EZH2 variant likely resulting in an expression switch from the large to small isoform. The remaining SNVs were anticipated to trigger Nonsense-Mediated Decay or shorten proteins. Conclusions: This study revealed that approximately 7% of SNVs found in a large group of AML patients have the potential to impact splicing. Notably, 1% of these SNVs had been classified as missense or nonsense changes. These findings provide support for the significant role of mis-splicing in the development of leukemia and emphasize the importance of devising novel approaches to effectively characterize driver mutations.

Integrative Genome and Transcriptome Sequencing Analysis Indicates Genetic and Epigenetic Dysregulation in DS-AML

Down Syndrome related AML is driven by GATA1 alterations in patients with trisomy 21. Using exome or targeted sequencing, prior studies identified GATA1 alterations in ~80-90% of patients. We performed whole genome sequencing coupled with whole transcriptome sequencing on 207 cases to study the genomic basis of Down Syndrome AML. We detected GATA1 alterations in 96.1% of cases, with additional structural rearrangements in GATA1 in 15% of cases that may have been missed in prior studies. For GATA1, although substitutions and small indels occur nearly uniformly across exon 2, we observed that internal tandem duplications (ITDs) are significantly enriched in the second half of exon 2, suggesting a specific mutational mechanism for these cases. We also detected exon 3 (instead of exon 2) deletion in one case, where the resultant truncated GATA1 protein is different from the commonly recognized sGATA1. Our study further revealed that mutations in genes mediating JAK-STAT signaling (JAK1/JAK2/JAK3), RAS pathway (KRAS/NRAS/NF1), Cohesin complex (STAG2/CTCF/RAD21/SMC3), as well as MBNL1, KANSL1, IRX1, and NFIA. By integrating the genome with transcriptome sequencing data, we discovered that GATA1 exon 2 skipping to be a significant event in DS-AML. Although exon 2 is nearly completely skipped in cases with exon 2 deletion or splice site alterations, significant exon 2 skipping is also observed in cases where the alteration is small and is in the middle of exon 2. Further, exon 2 skipping is also observed in cases wither the alteration is a single base substitution that results in stop codon in the middle of exon 2 (therefore splicing is unlikely affected by these alterations in such cases). Based on this observation, we propose a hybrid genetic-epigenetic model on the development of Down Syndrome AML. In DS-AML, GATA1 exon 2 skipping during transcription/splicing might be a developmentally (epigenetically) regulated event in early fetal development that is destined to be silenced in the postnatal period that results in activation of the canonical long GATA1. This epigenetic silencing of sGATA1 is overridden by secondary genetic events, thus maintaining sGATA1 as the predominant GATA1 protein. Notably, the sGATA1 have variable isoforms as a result of exon 2 or exon 3 loss. In summary, our integrated whole genome and transcriptome approach has resulted in discovery of novel and high-prevalence structural alterations in GATA1 and potentially novel genes involved in pathogenesis of DS-AML. Our integrated analysis provided evidence on the epigenetic/developmental regulation of GATA1 exon 2 skipping via alterative splicing in the context of trisomy 21 that warrants further investigation.

Nitric Oxide Modulates Ca2+ Leak and Arrhythmias via S-Nitrosylation of CaMKII.

Nitric oxide (NO) has been identified as a signaling molecule generated during β-adrenergic receptor stimulation in the heart. Furthermore, a role for NO in triggering spontaneous Ca2+ release via S-nitrosylation of CaMKIIδ (Ca2+/calmodulin kinase II delta) is emerging. NO donors are routinely used clinically for their cardioprotective effects on the heart, but it is unknown how NO donors modulate the proarrhythmic CaMKII to alter cardiac arrhythmia incidence. We test the role of S-nitrosylation of CaMKIIδ at the Cysteine-273 inhibitory site and cysteine-290 activating site in cardiac Ca2+ handling and arrhythmogenesis before and during β-adrenergic receptor stimulation. We measured Ca2+-handling in isolated cardiomyocytes from C57BL/6J wild-type (WT) mice and mice lacking CaMKIIδ expression (CaMKIIδ-KO) or with deletion of the S-nitrosylation site on CaMKIIδ at cysteine-273 or cysteine-290 (CaMKIIδ-C273S and -C290A knock-in mice). Cardiomyocytes were exposed to NO donors, S-nitrosoglutathione (GSNO; 150 μM), sodium nitroprusside (200 μM), and β-adrenergic agonist isoproterenol (100 nmol/L). Both WT and CaMKIIδ-KO cardiomyocytes responded to isoproterenol with a full inotropic and lusitropic Ca2+ transient response as well as increased Ca2+ spark frequency. However, the increase in Ca2+ spark frequency was significantly attenuated in CaMKIIδ-KO cardiomyocytes. The protection from isoproterenol-induced Ca2+ sparks and waves was mimicked by GSNO pretreatment in WT cardiomyocytes but lost in CaMKIIδ-C273S cardiomyocytes. When GSNO was applied after isoproterenol, this protection was not observed in WT or CaMKIIδ-C273S but was apparent in CaMKIIδ-C290A. In Langendorff-perfused isolated hearts, GSNO pretreatment limited isoproterenol-induced arrhythmias in WT but not CaMKIIδ-C273S hearts, while GSNO exposure after isoproterenol sustained or exacerbated arrhythmic events. We conclude that prior S-nitrosylation of CaMKIIδ at cysteine-273 can limit subsequent β-adrenergic receptor-induced arrhythmias, but that S-nitrosylation at cysteine-290 might worsen or sustain β-adrenergic receptor-induced arrhythmias. This has important implications for the administration of NO donors in the clinical setting.

Multiplex Prime Editing and PASSIGE TM for Non-Viral Generation of an Allogeneic CAR-T Cell Product

While CAR-T cell therapy represents a major advance in personalized immunotherapy, the autologous nature of commercially available CAR-T products have delayed its broad application beyond a subset of hematological malignancies. In particular, manufacturing autologous CAR-T therapies is costly and time-consuming, and success relies on the fitness of a patient's cells. An allogeneic off-the-shelf CAR-T product could overcome these cell quality and quantity issues and could be accessed on-demand. However, a successful allogeneic CAR-T product will require multiplex gene knockout in addition to stable CAR integration to prevent graft-versus-host disease (GvHD) and graft rejection by the patient's immune system. Strategies for the delivery and expression of CAR transgenes include semi-random integration using lentivirus or transposons, which risk unintended gene disruption or activation. Targeted integration can be achieved using nucleases in combination with a template for homology-directed repair (HDR), but efficiency of this approach is generally low and there are risks associated with the induction of double-strand breaks (DSBs), including p53 activation and chromothripsis. This is further complicated in a situation where multiplex editing is required, as multiple DSBs can lead to gross chromosomal rearrangements. Alternatively, base editors have been used for targeted gene disruption without the induction of DSBs via single nucleotide conversion to disrupt a splice site or introduce a single premature stop (pmSTOP) codon. However, this approach is limited to transition mutations and cannot be used to integrate large genetic cargo, which is required to generate CAR-T cells. Prime Editing (PE) can be used for precise and programmable gene disruption via multiple strategies, including introduction of multiple pmSTOP codons, splice site disruption, frameshift mutations, or deletion of large segments of regulatory or coding sequence. Further, Prime-Assisted Site-Specific Integrase Gene Editing (PASSIGE) can be used to precisely and flexibly integrate large genetic cargo at a specific locus. Together, PE-mediated gene knock out and PASSIGE can be tailored to generate a more broadly applicable, potentially safer, and more effective CAR-T cell product. To evaluate the efficacy of an all-PE non-viral approach to allogeneic CAR-T cell generation, PASSIGE and PE mediated gene knockout were used to generate CD19-CAR-T cells. Multiplex PE precisely disrupted expression of the endogenous T cell receptor alpha constant ( TRAC) and beta-2-microglobulin ( B2M) loci in over 90% of human T cells. Co-delivery of a non-viral DNA donor template with PASSIGE editing components resulted in targeted integration of a 3.5 kb CD19-CAR transgene expression cassette at the TRAC locus in over 60% of the T cells, with no observed impact on T cell viability, phenotype, or functionality. CD19 CAR-T cells generated using PASSIGE show potent anti-tumor activity and cytokine production in response to CD19 + tumor cell lines in vitro and in vivo. The PASSIGE-generated CD19 CAR-T cells reduce tumor burden and prolong survival of mice bearing CD19 + tumors. These results show that a PE platform can be used to generate multiplex edited CAR-T cells without the need for viral vectors and without causing DSBs. This modular, one-step, non-viral delivery Prime Editing platform expands the applicability of T cell therapies for the treatment of tumors and immune diseases.

MUC16 C terminal fragment activates YAP1 through Src signaling to promote gallbladder cancer growth

AbstractThe Hippo pathway is crucial to organ size control and its dysregulation contributes to tumorigenesis. The aberrant activation of YAP1 was identified in gallbladder cancer (GBC). However, the underlying mechanism and role in GBC remains unclear. The C terminal fragment of Mucin16, also known as carbohydrate antigen 125 (CA125) encoded product, MUC16c, plays extensive roles in tumor initiation and development. Our study showed that MUC16c binding with 14‐3‐3ε disrupted the interaction of 14‐3‐3ε and phosphorylated yes‐associated protein 1 (YAP1), which led to the activation of YAP1 in GBC. Furthermore, MUC16c decreased the phosphorylation of YAP1 at serine 397 (ser397) by inhibiting LATS1, which upregulated YAP1 protein stability. Interestingly, there was a potential Src kinase site in the MUC16c fragment. The MUC16c_del15Y polypeptides with the deletion of the Src kinase site promoted the interaction of YAP1 with 14‐3‐3ε and downregulated the YAP1 protein levels. Consistently, SU6656, a Src kinase inhibitor also blocked the activation of YAP1 by MUC16c. The MUC16c_del15Y polypeptides decreased GBC cell proliferation in vitro and the growth of xenograft tumors in vivo. Our study revealed the underlying mechanism of the activation of MUC16c on YAP1 mediated by Src signaling and the antitumor effect of MUC16c_del15Y, providing a potential target for GBC therapy.

The complete chloroplast genome of purple longan (Dimocarpus longan Lour., Sapindaceae)

Purple longan (Dimocarpus longan Lour.) is a new longan cultivar that arose in Soc Trang province, Vietnam. Although the economic value of purple longan has been revealed, genomic data have not been explored. In this study, the complete chloroplast genome of purple longan was sequenced and characterized, which was 160,763 bp in length. The genome had a quadripartite structure, including a large single copy (85,628 bp), a small single copy (18,247 bp), and two inverted repeat (28,444 bp) regions. This genome contained 79 protein-coding genes, 30 transfer RNAs, and four ribosomal RNAs, of which, 16 genes were duplicated in inverted repeat regions. Comparative genomic analysis revealed 11 highly variable regions (including matK-trnK_UUU, psbK-trnG_UCC, atpH-atpI, psbZ-rps14, pafI-trnL_UAA, psbJ-petG, clpP, rpl36-rpl14, rpl32-ccsA, rps15-ycf1, and ycf1). Additionally, 100 insertion and deletion sites were identified in the purple longan chloroplast genome. This study provided the first report on the complete chloroplast genome of purple longan, which is useful for further studies on cultivar identification, germplasm conservation, and plant breeding in the Dimocarpus genus and Sapindaceae family.