Cdc2 Gene Research Articles

The TFDP1 gene coding for DP1, the heterodimeric partner of the transcription factor E2F, is a target of deregulated E2F

The TFDP1 gene codes for the heterodimeric partner DP1 of the transcription factor E2F. E2F, principal target of the tumor suppressor pRB, plays central roles in cell proliferation by activating a group of growth-related genes. E2F also mediates tumor suppression by activating tumor suppressor genes such as ARF, an upstream activator of the tumor suppressor p53, when deregulated from pRB upon oncogenic changes. Among 8 E2F family members (E2F1∼E2F8), expression of activator E2Fs (E2F1∼E2F3a) is induced at the G1/S boundary of the cell cycle after growth stimulation by E2F itself. However, mechanisms regulating DP1 expression are not known.We show here that over-expression of E2F1 and forced inactivation of pRB, by adenovirus E1a, induced TFDP1 gene expression in human normal fibroblast HFFs, suggesting that the TFDP1 gene is a target of E2F. Serum stimulation of HFFs also induced TFDP1 gene expression, but with different kinetics from that of the CDC6 gene, a typical growth-related E2F target. Both over-expression of E2F1 and serum stimulation activated the TFDP1 promoter. We searched for E2F1-responsive regions by 5′ and 3’ deletion of the TFDP1 promoter and by introducing point mutations in putative E2F1-responsive elements. Promoter analysis identified several GC-rich elements, mutation of which reduced E2F1-responsiveness but not serum-responsiveness. ChIP assays showed that the GC-rich elements bound deregulated E2F1 but not physiological E2F1 induced by serum stimulation. These results suggest that the TFDP1 gene is a target of deregulated E2F. In addition, knockdown of DP1 expression by shRNA enhanced ARF gene expression, which is specifically induced by deregulated E2F activity, suggesting that activation of the TFDP1 gene by deregulated E2F may function as a failsafe feedback mechanism to suppress deregulated E2F and maintain normal cell growth in the event that DP1 expression is insufficient relative to that of its partner activator E2Fs.a maximum of 6 keywords: E2F, DP1, TFDP1 gene, pRB, gene expression.

Genetic diagnosis of microcephaly

Objective: To explore the diagnostic value of chromosome karyotype analysis, chromosomal microarray analysis (CMA) and whole exome sequencing (WES) in microcephaly. Methods: A total of 9 cases of microcephaly fetuses diagnosed by prenatal ultrasound or children with microcephaly diagnosed after birth were selected from the Sixth Affiliated Hospital of Guangzhou Medical University from January 2014 to August 2022.Karyotype analysis and/or CMA were used to detect. The cases with negative karyotype analysis and CMA results were further sequenced by trio-based WES (Trio-WES). Then the coding genes contained in the pathogenic copy number variation (CNV) fragments were analyzed by gene ontology (GO) enrichment. The genes related to the development of the central nervous system contained in the pathogenic CNV and the pathogenic genes found by Trio-WES were combined for gene interaction network analysis. Results: In this study, 9 cases of microcephaly were recruited, with the time of diagnosis ranged from 23 weeks of gestation to 7 years after birth, and the head circumference of fetus or children ranged from 18.3 to 42.5 cm (-7SD to -2SD). Karyotype analysis was detected in all 9 cases and no abnormality result was found. Eight cases were detected by CMA, and one abnormal was found. Five cases were detected by Trio-WES, and two cases were detected with likely pathogenic genes. The GO enrichment analysis of the coding gene in the 4p16.3 microdeletion (pathogenic CNV) region showed that: in biological process, it was mainly concentrated in phototransduction, visible light; in terms of molecular function, it was mainly concentrated in fibroblast growth factor binding; in terms of cell components, it was mainly concentrated in rough endoplasmic reticulum. Gene interaction network analysis suggested that CDC42 gene could interact with CTBP1, HTT and ASPM gene. Conclusions: CMA could be used as a first-line detection technique for microcephaly. When the results of chromosome karyotype analysis and/or CMA are negative, Trio-WES could improve the detection rate of pathogenicity of microcephaly.

Parkinson’s Disease as a Risk Factor for Prostate Adenocarcinoma: A Molecular Point of View

Introduction: Cancer and neurodegeneration are two major leading causes of morbidity and death worldwide. Neurodegeneration results in excessive neuronal cell death, and cancer emerges from increased proliferation and resistance to cell death. Although most epidemiological studies support an inverse association between the risk for the development of neurodegenerative diseases and cancer, increasing evidence points to a positive correlation between specific types of cancer, like prostate adenocarcinoma (PRAD), and neurodegenerative diseases, like Parkinson’s disease (PD). Methods: PD and PRAD differential genes were screened through the GEO database, and the differential genes were analyzed using David, String, GEPIA, Kaplan-Meier plotter, TIMER2.0, proteinatlas, cBioPortal, and CTD databases to elucidate the biological function and molecular mechanism of PD and PRAD-related genes. Results: Studies have shown that the hub gene and differentially expressed genes (DEGs) in PD were differentially expressed in PRAD, including CDC20, HSPA4L, ROBO1, DMKN, IFI27L2, LUZP2, PTN, PTGDS. In PRAD, the high expression of HSPA4L, ROBO1, DMKN, IFI27L2, PTN, and PTGDS genes was associated with longer survival, while the patients with low expression of CDC20 and LUZP2 genes had longer survival. The mRNA of CDC20 and LUZP2 were highly expressed, while the mRNAs of HSPA4L, ROBO1, DMKN, IFI27L2, and PTGDS were low expressed. Gene methylation did not affect the survival of patients. The high expression of miR-142, miR-186, miR-30a, miR-497, miR-590, miR-28, and miR-576 in microRNA (miRNA) might potentially be used as biomarkers for the progression of PD and PRAD and for the early diagnosis of PD and PRAD in the populations. The genes in this study were highly associated with B cells, CD8+ T cells, CD4+ T cells, macrophages, neutrophils, and dendritic cells. Somatic mutation mainly focused on missense mutation. Therapeutic drugs included acetaminophen and valproic acid (VPA). Conclusion: Bioinformatics was used to identify potential targets and novel molecular mechanisms that may serve as clinical markers for the diagnosis and treatment of PD and PRAD.

Hemocyte proliferation is associated with blood color shade variation in the blood clam, Tegillarca granosa

Blood color shade is closely related to the health status and nutritional value of the blood clam, Tegillarca granosa. The blood color shade of T. granosa shows great variation and is considered as an economically importantly trait. However, the molecular regulatory mechanism of blood color shade variation is unclear. In this study, the total hemocyte count (THC) and hemoglobin concentration (HGC) were verified to be related to blood color shade. RNA-seq analysis was performed to explore the blood color shade-related genes in T. granosa. Transcriptome analysis revealed 399 and 467 genes that were exclusively highly expressed in light-blood clams (HGC > 45.7 g/L, designated TL) and dark-blood clams (HGC < 31.3 g/L, designated TH), respectively. Differentially expressed genes were enriched in cell cycle, and several key genes (such as CDC42 and CDC20) involved in hematopoietic processes were upregulated in the TH group, which means that the variation of blood color shade is probably related to hematopoietic cell proliferation. Knockdown of CDC42 gene expression resulted in a significant reduction in THC in blood clams, and EdU staining revealed that cell proliferation activity of the clam gills is higher in the TH group than in the TL group, which confirmed our assumption. The present study improves our understanding of the molecular mechanisms underlying blood color shade variation in marine clams and facilitates the selection of blood clams with higher hemoglobin contents.

Evaluation of BDE-47-induced neurodevelopmental toxicity in zebrafish embryos.

There are growing concerns about the neurodevelopmental toxicity of polybrominated diphenyl ethers (PBDEs), but the toxicological phenotypes and mechanisms are not well elucidated. Here, zebrafish (Danio rerio) were exposed to 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) from 4 to 72 h post-fertilization (hpf). The results showed that BDE-47 stimulated the production of dopamine and 5-hydroxytryptamine, but inhibited expression of Nestin, GFAP, Gap43, and PSD95 in 24 hpf embryos. Importantly, we unraveled the inhibitory effects of BDE-47 on neural crest-derived melanocyte differentiation and melanin syntheses process, evidenced by disrupted expression of wnt1, wnt3, sox10, mitfa, tyrp1a, tyrp1b, tryp2, and oca2 gene in 72 hpf embryos and decreased tyrosinase activities in embryos at 48 and 72 hpf. The transcriptional activities of myosin VAa, kif5ba, rab27a, mlpha, and cdc42 genes, which are associated with intracellular transport process, were also disturbed during zebrafish development. Ultimately, these alterations led to fast spontaneous movement and melanin accumulation deficit in zebrafish embryos upon BDE-47 exposure. Our results provide an important extension for understanding the neurodevelopmental effects of PBDEs and facilitate the comprehensive evaluation of neurotoxicity in embryos.

Cdc14 phosphatase contributes to cell wall integrity and pathogenesis in Candida albicans.

The Cdc14 phosphatase family is highly conserved in fungi. In Saccharomyces cerevisiae, Cdc14 is essential for down-regulation of cyclin-dependent kinase activity at mitotic exit. However, this essential function is not broadly conserved and requires only a small fraction of normal Cdc14 activity. Here, we identified an invariant motif in the disordered C-terminal tail of fungal Cdc14 enzymes that is required for full enzyme activity. Mutation of this motif reduced Cdc14 catalytic rate and provided a tool for studying the biological significance of high Cdc14 activity. A S. cerevisiae strain expressing the reduced-activity hypomorphic mutant allele (cdc14hm ) as the sole source of Cdc14 proliferated like the wild-type parent strain but exhibited an unexpected sensitivity to cell wall stresses, including chitin-binding compounds and echinocandin antifungal drugs. Sensitivity to echinocandins was also observed in Schizosaccharomyces pombe and Candida albicans strains lacking CDC14, suggesting this phenotype reflects a novel and conserved function of Cdc14 orthologs in mediating fungal cell wall integrity. In C. albicans, the orthologous cdc14hm allele was sufficient to elicit echinocandin hypersensitivity and perturb cell wall integrity signaling. It also caused striking abnormalities in septum structure and the same cell separation and hyphal differentiation defects previously observed with cdc14 gene deletions. Since hyphal differentiation is important for C. albicans pathogenesis, we assessed the effect of reduced Cdc14 activity on virulence in Galleria mellonella and mouse models of invasive candidiasis. Partial reduction in Cdc14 activity via cdc14hm mutation severely impaired C. albicans virulence in both assays. Our results reveal that high Cdc14 activity is important for C. albicans cell wall integrity and pathogenesis and suggest that Cdc14 may be worth future exploration as an antifungal drug target.

Targeting the anaphase-promoting complex/cyclosome (APC/C) enhanced antiproliferative and apoptotic response in bladder cancer

Improving the chemotherapy sensitivity of bladder cancer is a current clinical challenge. It is critical to seek out effective combination therapies that include low doses of cisplatin due to its dose-limiting toxicity. This study aims to investigate the cytotoxic effects of the combination therapy including proTAME, a small molecule inhibitor, targeting Cdc-20 and to determine the expression levels of several APC/C pathway-related genes that may play a role in the chemotherapy response of RT-4 (bladder cancer) and ARPE-19 (normal epithelial) cells. The IC20 and IC50 values were determined by MTS assay. The expression levels of apoptosis-associated (Bax and Bcl-2) and APC/C-associated (Cdc-20, Cyclin-B1, Securin, and Cdh-1) genes were assessed by qRT-PCR. Cell colonization ability and apoptosis were examined by clonogenic survival experiment and Annexin V/PI staining, respectively. Low-dose combination therapy showed a superior inhibition effect on RT-4 cells by increasing cell death and inhibiting colony formation. Triple-agent combination therapy further increased the percentage of late apoptotic and necrotic cells compared to the doublet-therapy with gemcitabine and cisplatin. ProTAME-containing combination therapies resulted in an elevation in Bax/Bcl-2 ratio in RT-4 cells, while a significant decrease was observed in proTAME-treated ARPE-19 cells. Cdc-20 expression in proTAME combined treatment groups were found to be decreased compared to their control groups. Low-dose triple-agent combination induced cytotoxicity and apoptosis in RT-4 cells effectively. It is essential to evaluate the role of APC/C pathway-associated potential biomarkers as therapeutic targets and define new combination therapy regimens to achieve improved tolerability in bladder cancer patients in the future.

THERMAL TOLERANCE PHENOTYPE IN CDC13-1 EXO1 HETEROZYGOUS DIPLOIDS OF S. CEREVISIAE IS A DOMINANT TRAIT

Background: Telomeric DNA is found at the end of eukaryotic chromosomes, where they play a role in protecting the chromosome and the integrity of the genome of the organism through the activity of telomerase. Saccharomyces cerevisiae exists in two genotypes: haploid and diploid. Temperature sensitive point mutation on the cdc13 gene of each genotype and deletion of exo1 gene (cdc13-1Exo1 mutants) give rise to mutant survivors at enhanced temperatures. The mode of inheritance of the thermal tolerance allele in the heterozygous diploid genotype is not known. Materials and Methods: We constructed diploids by mating temperature sensitive haploid strains of opposite mating type cdc13-1 exo1: LEU with temperature resistant strains of cdc13-1 exo1::HIS. The crosses were 1296x3182 (D) and 2561x3181 (C). Using a sterile stick, smear of one haploid strain was made on each YEPD plates labelled C2, C8, C10, D4, D10, and D113. A smear of another opposite mating type was made on the previous strain. They were mixed and allowed to mate for six hours, before culturing on media lacking Luecine and Histidine (–L and –H) to purify and confirm that they are diploids. After confirmation, a loop full aliquot of the diploids were streaked on sterile media lacking leucine and histidine (-L, -H) and on YEPD and cultured at 370C to check thermal tolerance and number of viable colonies from each diploid crosses in (cfu). Result: The heterozygous diploid D thrived at the enhanced temperature of 370C and there is a significant difference in the yield of viable colonies by the D diploids when compared to the yield of the C diploids with P-value of 0.05. Conclusion: The growth of diploid D10 as shown in plate 3.1 establishes that, temperature resistant allele inherited by cdc13-1 exo1heterozygous diploids is a dominant phenotype, and its mode of inheritance is dominant as the heterozygous diploid thrived at the enhanced temperature of 370C.

Splenectomy as an effective treatment for macrothrombocytopenia in Takenouchi-Kosaki syndrome.

Takenouchi-Kosaki syndrome (TKS) is a rare congenital disease caused by a de novo heterozygous mutation in the CDC42 gene. Its characteristic clinical features are macrothrombocytopenia, developmental delay, dysmorphic facial features, and deafness. Splenectomy has been contraindicated for inherited thrombocytopenia, and there is little information on treatment of macrothrombocytopenia in TKS. In a previously reported case of autoimmune hemolytic anemia (AIHA) with TKS, we observed that AIHA initially resolved with prednisolone, but gradually became refractory to drug therapy. After splenectomy, both anemia and macrothrombocytopenia improved. This is a novel positive effect of splenectomy for thrombocytopenia in TKS, although further studies are required to assess the effectiveness and safety of splenectomy.

Chromatin structure undergoes global and local reorganization during murine dendritic cell development and activation

Classical dendritic cells (cDCs) are essential for immune responses and differentiate from hematopoietic stem cells via intermediate progenitors, such as monocyte-DC progenitors (MDPs) and common DC progenitors (CDPs). Upon infection, cDCs are activated and rapidly express host defense-related genes, such as those encoding cytokines and chemokines. Chromatin structures, including nuclear compartments and topologically associating domains (TADs), have been implicated in gene regulation. However, the extent and dynamics of their reorganization during cDC development and activation remain unknown. In this study, we comprehensively determined higher-order chromatin structures by Hi-C in DC progenitors and cDC subpopulations. During cDC differentiation, chromatin activation was initially induced at the MDP stage. Subsequently, a shift from inactive to active nuclear compartments occurred at the cDC gene loci in CDPs, which was followed by increased intra-TAD interactions and loop formation. Mechanistically, the transcription factor IRF8, indispensable for cDC differentiation, mediated chromatin activation and changes into the active compartments in DC progenitors, thereby possibly leading to cDC-specific gene induction. Using an infection model, we found that the chromatin structures of host defense-related gene loci were preestablished in unstimulated cDCs, indicating that the formation of higher-order chromatin structures prior to infection may contribute to the rapid responses to pathogens. Overall, these results suggest that chromatin structure reorganization is closely related to the establishment of cDC-specific gene expression and immune functions. This study advances the fundamental understanding of chromatin reorganization in cDC differentiation and activation.

Transcriptome Analysis of Sugarcane Young Leaves and Protoplasts after Enzymatic Digestion.

Sugarcane somatic cell hybridization can break through the barrier of genetic incompatibility between distantly related species in traditional breeding. However, the molecular mechanisms of sugarcane protoplast regeneration and the conditions for protoplast preparation remain largely unknown. In this study, young sugarcane (ROC22) leaves were enzymatically digested, and the viability of protoplasts reached more than 90% after enzymatic digestion (Enzymatic combination: 2% cellulase + 0.5% pectinase + 0.1% dissociative enzyme + 0.3% hemicellulase, pH = 5.8). Transcriptome sequencing was performed on young sugarcane leaves and protoplasts after enzymatic digestion to analyze the differences in gene expression in somatic cells before and after enzymatic digestion. A total of 117,411 unigenes and 43,460 differentially expressed genes were obtained, of which 21,123 were up-regulated and 22,337 down-regulated. The GO terms for the 43,460 differentially expressed genes (DEGs) were classified into three main categories: biological process, cellular component and molecular function, which related to developmental process, growth, cell proliferation, transcription regulator activity, signal transducer activity, antioxidant activity, oxidative stress, kinase activity, cell cycle, cell differentiation, plant hormone signal transduction, and so on. After enzymatic digestion of young sugarcane leaves, the expressions of GAUT, CESA, PSK, CyclinB, CyclinA, CyclinD3 and cdc2 genes associated with plant regeneration were significantly down-regulated to 65%, 47%, 2%, 18.60%, 21.32%, 52% and 45% of young leaves, respectively. After enzymatic digestion, Aux/IAA expression was up-regulated compared with young leaves, and Aux/IAA expression was 3.53 times higher than that of young leaves. Compared with young leaves, these key genes were significantly changed after enzymatic digestion. These results indicate that the process of somatic enzymatic digestion process may affect the regeneration of heterozygous cells to a certain extent.

The Cdc25/Ras/cAMP-dependent protein kinase A signaling pathway regulates proline utilization in wine yeast Saccharomyces cerevisiae under a wine fermentation model.

Proline is a predominant amino acid in grape must, but it is poorly utilized by the yeast Saccharomyces cerevisiae in wine-making processes. This sometimes leads to a nitrogen deficiency during fermentation and proline accumulation in wine. In this study, we clarified that a glucose response is involved in an inhibitory mechanism of proline utilization in yeast. Our genetic screen showed that strains with a loss-of-function mutation on the CDC25 gene can utilize proline even under fermentation conditions. Cdc25 is a regulator of the glucose response consisting of the Ras/cAMP-dependent protein kinase A (PKA) pathway. Moreover, we found that activation of the Ras/PKA pathway is necessary for the inhibitory mechanism of proline utilization. The present data revealed that crosstalk exists between the carbon and proline metabolisms. Our study could hold promise for the development of wine yeast strains that can efficiently assimilate proline during the fermentation processes.

Alcohol consumption, blood DNA methylation and breast cancer: a Mendelian randomisation study

Alcohol intake is thought to be a risk factor for breast cancer, but the causal relationship and carcinogenic mechanisms are not clear. We performed an up-to-date meta-analysis of prospective studies to assess observational association, and then conducted MR analysis to make causal inference based on the genetic predisposition to alcohol consumption (“drinks per week”) and pathological drinking behaviours (“alcohol use disorder” and “problematic alcohol use”), as well as genetically predicted DNA methylation at by alcohol-related CpG sites in blood. We found an observational dose–response association between alcohol intake and breast cancer incidence with an additional risk of 4% for per 10 g/day increase in alcohol consumption. Genetic predisposition to alcohol consumption (“drinks per week”) was not causally associated with breast cancer incidence at the OR of 1.01 (95% CI 0.84, 1.23), but problematic alcohol use (PAU) was linked to a higher breast cancer risk at the OR of 1.76 (95% CI 1.04, 2.99) when conditioning on alcohol consumption. Epigenetic MR analysis identified four CpG sites, cg03260624 near CDC7 gene, cg10816169 near ZNF318 gene, cg03345232 near RIN3 gene, and cg26312998 near RP11-867G23.13 gene, where genetically predicted epigenetic modifications were associated with an increased breast cancer incidence risk. Our findings re-affirmed that alcohol consumption is of high risk for breast cancer incidence even at a very low dose, and the pathogenic effect of alcohol on breast cancer could be due to pathological drinking behaviour and epigenetic modification at several CpG sites, which could be potential intervention targets for breast cancer prevention.

A novel lncRNA-miRNA-mRNA triple network identifies lncRNA XIST as a biomarker for acute myocardial infarction.

Despite the well-established role of long non-coding RNAs (lncRNAs) across various biological processes, their mechanisms in acute myocardial infarction (AMI) are not fully elucidated. The GSE34198 dataset from the Gene Expression Omnibus (GEO) database, which comprised 49 specimens from individuals with AMI and 47 specimens from controls, was extracted and analysed using the weighted gene co-expression network analysis (WGCNA) package. Twenty-seven key genes were identified through a combination of the degree and gene significance (GS) values, and the CDC42 (degree = 64), JAK2 (degree = 41), and CHUK (degree = 30) genes were identified as having the top three-degree values among the 27 genes. Potential interactions between lncRNA, miRNAs and mRNAs were predicted using the starBase V3.0 database, and a lncRNA-miRNA-mRNA triple network containing the lncRNA XIST, twenty-one miRNAs and three hub genes (CDC42, JAK2 and CHUK) was identified. RT–qPCR validation showed that the expression of the JAK2 and CDC42 genes and the lncRNA XIST was noticeably increased in samples from patients with AMI compared to normal samples. Pearson’s correlation analysis also proved that JAK2 and CDC42 expression levels correlated positively with lncRNA XIST expression levels. The area under ROC curve (AUC) of lncRNA XIST was 0.886, and the diagnostic efficacy of the lncRNA XIST was significantly better than that of JAK2 and CDC42. The results suggested that the lncRNA XIST appears to be a risk factor for AMI likely through its ability to regulate JAK2 and CDC42 gene expressions, and it is expected to be a novel and reliable biomarker for the diagnosis of AMI.

TIP60 acts as a regulator of genes involved in filopodia formation and cell migration during wound healing

Wound healing is a complex phenomenon that requires coordination of numerous molecular and cellular changes to facilitate timely and efficient repair of the damaged tissue. Although many of these molecular pathways have been detailed, others remain to be elucidated. In the present work, we show for the first time, roles for the acetyltransferase TIP60 and nuclear receptor transcription factor PXR in this process, participating in wound healing by altering actin dynamics and cellular motility. We found that in response to wound-injury, TIP60 induces rapid formation of filopodia at the wounded cell front, leading to enhanced cell migration and faster closure of the wound. Further, qPCR analysis revealed heightened expression of Cdc42 and ROCK1 genes, key regulators involved in filopodia formation and actin reorganization, exclusively in TIP60-PXR-expressing cells upon wound-induction. We also performed ChIP assays to confirm the context-specific binding of TIP60 on the ROCK1 promoter and demonstrated that the TIP60 chromodomain is essential for loading of the TIP60–PXR complex onto the chromatin. Results from immunoprecipitation assays revealed that during the wounded condition, TIP60 alters the chromatin microenvironment by specifically acetylating histones H2B and H4, thereby modulating the expression of target genes. Overall, findings of this study show that TIP60 is a novel regulator of the wound healing process by regulating the expression of wound repair-related genes.

Trapping of CDC42 C-terminal variants in the Golgi drives pyrin inflammasome hyperactivation.

Mutations in the C-terminal region of the CDC42 gene cause severe neonatal-onset autoinflammation. Effectiveness of IL-1β-blocking therapy indicates that the pathology involves abnormal inflammasome activation; however, the mechanism underlying autoinflammation remains to be elucidated. Using induced-pluripotent stem cells established from patients carrying CDC42R186C, we found that patient-derived cells secreted larger amounts of IL-1β in response to pyrin-activating stimuli. Aberrant palmitoylation and localization of CDC42R186C protein to the Golgi apparatus promoted pyrin inflammasome assembly downstream of pyrin dephosphorylation. Aberrant subcellular localization was the common pathological feature shared by CDC42 C-terminal variants with inflammatory phenotypes, including CDC42*192C*24 that also localizes to the Golgi apparatus. Furthermore, the level of pyrin inflammasome overactivation paralleled that of mutant protein accumulation in the Golgi apparatus, but not that of the mutant GTPase activity. These results reveal an unexpected association between CDC42 subcellular localization and pyrin inflammasome activation that could pave the way for elucidating the mechanism of pyrin inflammasome formation.

Identification of Candidate Genes for Pigmentation in Camels Using Genotyping-by-Sequencing.

Simple SummaryThe coat color of dromedary is usually uniform and varies from black to white. We identified 9 significant SNPs associated with white color, and the 13 significant SNPs associated with black color using genotyping-by-sequencing (GBS). Among candidate genes, SNAI1 that interacts with MCIR, ASIP and KIT genes plays a key role in the melanin biosynthetic and pigmentation biological process and melanogenesis biological pathway.The coat color of dromedary is usually uniform and varies from black to white, although dark- to light-brown colors are the most common phenotypes. This project was designed to gain knowledge on novel color-related variants using genotyping-by-sequencing (GBS). The association between the SNPs and coat color was tested using MLM (mixed linear models) with kinship matrix. Three GWAS models including white color vs. non-white color, black vs. non-black color, and light-brown vs. dark-brown color were performed. There were no distinct genetic clusters detected based on the color phenotypes. However, admixture occurred among all individuals of the four different coat color groups. We identified nine significant SNPs associated with white color after Bonferroni correction, located close to ANKRD26, GNB1, TSPYL4, TEKT5, DEXI, CIITA, TVP23B, CLEC16A, TMPRSS13, FXYD6, MPZL3, ANKRD26, HFM1, CDC7, TGFBR3, and HACE1 genes in neighboring flanking regions. The 13 significant SNPs associated with black color and the candidate genes were: CAPN7, CHRM4, CIITA, CLEC16A, COL4A4, COL6A6, CREB3L1, DEXI, DGKZ, DGKZ, EAF1, HDLBP, INPP5F, MCMBP, MDK, SEC23IP, SNAI1, TBX15, TEKT5, TMEM189, trpS, TSPYL4, TVP23B, and UBE2V1. The SNAI1 gene interacted with MCIR, ASIP and KIT genes. These genes play a key role in the melanin biosynthetic and pigmentation biological process and melanogenesis biological pathway. Further research using a larger sample size and pedigree data will allow confirmation of associated SNPs and the identified candidate genes.

Rho GTPase gene expression and breast cancer risk: a Mendelian randomization analysis

The Rho GTPase family consists of 20 genes encoding intracellular signalling proteins that influence cytoskeletal dynamics, cell migration and cell cycle progression. They are implicated in breast cancer progression but their role in breast cancer aetiology is unknown. As aberrant Rho GTPase activity could be associated with breast cancer, we aimed to determine the potential for a causal role of Rho GTPase gene expression in breast cancer risk, using two-sample Mendelian randomization (MR). MR was undertaken in 122,977 breast cancer cases and 105,974 controls, including 69,501 estrogen receptor positive (ER+) cases and 105,974 controls, and 21,468 ER negative (ER−) cases and 105,974 controls. Single nucleotide polymorphisms (SNPs) underlying expression quantitative trait loci (eQTLs) obtained from normal breast tissue, breast cancer tissue and blood were used as genetic instruments for Rho GTPase expression. As a sensitivity analysis, we undertook co-localisation to examine whether findings reflected shared causal variants or genomic confounding. We identified genetic instruments for 14 of the 20 human Rho GTPases. Using eQTLs obtained from normal breast tissue and normal blood, we identified evidence of a causal role of RHOD in overall and ER+ breast cancers (overall breast cancer: odds ratio (OR) per standard deviation (SD) increase in expression level 1.06; (95% confidence interval (CI) 1.03, 1.09; P = 5.65 × 10–5) and OR 1.22 (95% CI 1.11, 1.35; P = 5.22 × 10–5) in normal breast tissue and blood respectively). There was a consistent direction of association for ER− breast cancer, although the effect-estimate was imprecisely estimated. Using eQTLs from breast cancer tissue and normal blood there was some evidence that CDC42 was negatively associated with overall and ER + breast cancer risk. The evidence from colocalization analyses strongly supported our MR results particularly for RHOD. Our study suggests a potential causal role of increased RHOD gene expression, and, although the evidence is weaker, a potential protective role for CDC42 gene expression, in overall and ER+ breast cancers. These finding warrant validation in independent samples and further biological investigation to assess whether they may be suitable targets for drug targeting.

Role of F-box Protein Cdc4 in Fungal Virulence and Sexual Reproduction of Cryptococcus neoformans.

Cryptococcus neoformans is an opportunistic yeast-like pathogen that mainly infects immunocompromised individuals and causes fatal meningitis. Sexual reproduction can promote the exchange of genetic material between different strains of C. neoformans, which is one of the reasons leading to the emergence of highly pathogenic and drug-resistant strains of C. neoformans. Although much research has been done on the regulation mechanism of Cryptococcus sexual reproduction, there are few studies on the sexual reproduction regulation of Cryptococcus by the ubiquitin-proteasome system. This study identified an F-box protein, Cdc4, which contains a putative F-box domain and eight WD40 domains. The expression pattern analysis showed that the CDC4 gene was expressed in various developmental stages of C. neoformans, and the Cdc4 protein was localized in the nucleus of cryptococcal cells. In vitro stress responses assays showed that the CDC4 overexpression strains are sensitive to SDS and MMS but not Congo red, implying that Cdc4 may regulate the cell membrane integrity and repair of DNA damage of C. neoformans. Fungal virulence assay showed that although the cdc4Δ mutant grows normally and can produce typical virulence factors such as capsule and melanin, the cdc4Δ mutant completely loses its pathogenicity in a mouse systemic-infection model. Fungal mating assays showed that Cdc4 is also essential for fungal sexual reproduction in C. neoformans. Although normal mating hyphae were observed during mating, the basidiospores’ production was blocked in bilateral mating between cdc4Δ mutants. Fungal nuclei development assay showed that the nuclei failed to undergo meiosis after fusion inside the basidia during the bilateral mating of cdc4Δ mutants, indicating that Cdc4 is critical to regulating meiosis during cryptococcal mating. In summary, our study revealed that the F-box protein Cdc4 is critical for fungal virulence and sexual reproduction in C. neoformans.

Abstract PR-12: Novel targeted combination therapy to reduce health disparity in high-risk B-cell acute lymphoblastic leukemia in Hispanic/Latino children

Abstract Hispanic/Latino (H/L) children and adolescents have a 40% higher death rate than non-Hispanic whites (NHW) after correcting socioeconomic factors. Recently, we identified an increased incidence of deletion of one IKZF1 allele in H/L children, which provided a biological rationale for the worse prognosis of B-cell acute lymphoblastic leukemia (B-ALL) in this population. The very high incidence (29%) makes the deletion of one IKZF1 allele the most frequent genetic alteration that confers adverse prognosis in B-ALL in H/L children. The IKZF1 gene encodes a DNA-binding protein, Ikaros, which functions as a transcriptional regulator. Our goal is to determine the mechanism through which Ikaros regulates leukemia progression and to develop the novel therapy to treat B-ALL with deletion of one IKZF1 allele to reduce the health disparity in survival for H/L children with B-ALL. Global DNA-binding analysis of primary B-ALL cells from H/L children showed that Ikaros binds to the promoters of CDC20 and ANAPC7 genes. CDC20 and ANAPC7 genes have a critical role in mitosis progression and are essential for cellular proliferation. The role of Ikaros in the regulation of CDC20 and ANAPC7 expression in B-ALL of H/L children was established using gain-of-function and loss-of-function experiments. Overexpression of Ikaros in B-ALL cells results in reduced expression of CDC20 and ANAPC7, while Ikaros knock-down results in increased transcription of CDC20 and ANAPC7 in B-ALL. Since Ikaros function in hematopoietic malignancies is regulated by pro-oncogenic Casein Kinase 2 (CK2), we tested whether CK2 can control the ability of Ikaros to regulate the expression of CDC20 and ANAPC7 in B-ALL. Increased expression of CK2 in B-ALL results in increased expression of CDC20 and ANAPC7 genes due to the loss of Ikaros binding to the promoters of CDC20 and ANAPC7 genes. Inhibition of CK2 with shRNA and/or a specific CK2 inhibitor, CX-4945, restores Ikaros binding to promoters of CDC20 and ANAPC7 in high-risk B-ALL with deletion of one IKZF1 allele in H/L children. Restoration of Ikaros binding to promoters of CDC20 and ANAPC7 in high-risk B-ALL in H/L children results in reduced expression of these genes and cell cycle arrest. CK2 inhibition sensitizes B-ALL cells to treatment with an inhibitor of mitosis – vincristine. Combination treatment with CK2 inhibitor and vincristine showed a synergistic effect on B-ALL cells from H/L children. In summary, presented data demonstrate that IKAROS and CK2 regulate the progression of mitosis in high-risk B-ALL in Hispanic/Latino children. Results suggest that the combination treatment with CK2 inhibitors and vincristine can be an efficient novel treatment to reduce the health disparity in survival for Hispanic/Latino children with B-ALL. Citation Format: Sinisa Dovat, Dimant Desai, Arati Sharma, Chandrika Gowda. Novel targeted combination therapy to reduce health disparity in high-risk B-cell acute lymphoblastic leukemia in Hispanic/Latino children [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PR-12.