Complex Mutations Research Articles

The Bi-Steric Inhibitor RMC-5552 Reduces mTORC1 Signaling and Growth in Lymphangioleiomyomatosis.

Mutations in the Tuberous Sclerosis Complex (TSC) genes result in the hyperactivation of the mechanistic/mammalian target of rapamycin 1 (mTORC1) growth pathway in mesenchymal pulmonary cells. Rapamycin (SirolimusTM), a naturally occurring macrolide, is the only therapeutic approved for women with lymphangioleiomyomatosis (LAM), a progressive, destructive lung disease caused by TSC gene mutations and mTORC1 hyperactivation. However, on cessation of the drug, lung function decline continues. We demonstrated here that pulmonary LAM cancer stem-like cells (SLS) most highly expressed the eukaryotic translation initiation factor 4E (eIF4E)-dependent translation initiation genes. We also showed that the eukaryotic initiation factor 4E-binding protein 1 (4E-BP1) gene has the lowest expression in these cells, indicating that the 4E-BP1/eIF4E ratio in LAM SLS cells favors unrestrained eIF4E oncogenic mRNA translation. The bi-steric mTORC1-selective compound RMC-5552 prevented growth of LAM-associated fibroblasts (LAFs) and phosphorylation of proteins in the ribosomal protein S6K1/ribosomal protein S6 (S6K1/S6) and 4E-BP1/eIF4E translation mTORC1-driven pathways, whereas rapamycin only blocked the S6K/S6 axis. Rapamycin inhibition of LAF growth was rapidly reversed, but RMC-5552 inhibition was more durable. RMC-5552, through its potential to eradicate LAM cancer SLS cells, may have therapeutic benefit in LAM and other diseases with mTORC1 hyperactivity.

Analysis of TRIOBP gene in non-syndromic deafness: A case report.

Through family investigation, the genetic map was drawn and audiological characteristics were analyzed. High-throughput sequencing was used to screen the deafness genes of the proband. Sanger sequencing was used to verify the suspected pathogenic sites in the family. Identify the causes of hearing loss and treatment options. Bilateral moderate to severe sensorineural deafness. After completing the examination, the patient was recommended to wear a hearing aid or do a cochlear implant, but the patient was not treated for personal reasons. All 8 patients in this family were nonsyndromic deafness. The proband had a compound heterozygous mutation of c.A4484T/c.A4510G in the TRIOBP gene, and the patient II-6 had a heterozygous mutation of c.A4484T in the TRIOBP gene. A complex heterozygous mutation of TRIOBP gene c.A4510G/c.G59T was found in II-7, but no reports of pathogenicity of these mutations were found in relevant literatures and databases. In addition, patients II-6, III-4, and III-6 had heterozygous mutations of CHD7 gene c.T2615C and C.3202-5T >C, and patients II-6 and III-4 also had heterozygous mutations of CHD23 gene c.G5312A and c.C6250T. In this study, a new locus of the TRIOBP gene was found, which enriched the gene mutant spectrum and clarified the pathogenic gene of the proband. However, the etiology of deafness in other members of the family needs to be further analyzed.

Pre-clinical development of AP4B1 gene replacement therapy for hereditary spastic paraplegia type 47.

Spastic paraplegia 47 (SPG47) is a neurological disorder caused by mutations in the adaptor protein complex 4 β1 subunit (AP4B1) gene leading to AP-4 complex deficiency. SPG47 is characterised by progressive spastic paraplegia, global developmental delay, intellectual disability and epilepsy. Gene therapy aimed at restoring functional AP4B1 protein levels is a rational therapeutic strategy to ameliorate the disease phenotype. Here we report that a single delivery of adeno-associated virus serotype 9 expressing hAP4B1 (AAV9/hAP4B1) into the cisterna magna leads to widespread gene transfer and restoration of various hallmarks of disease, including AP-4 cargo (ATG9A) mislocalisation, calbindin-positive spheroids in the deep cerebellar nuclei, anatomical brain defects and motor dysfunction, in an SPG47 mouse model. Furthermore, AAV9/hAP4B1-based gene therapy demonstrated a restoration of plasma neurofilament light (NfL) levels of treated mice. Encouraged by these preclinical proof-of-concept data, we conducted IND-enabling studies, including immunogenicity and GLP non-human primate (NHP) toxicology studies. Importantly, NHP safety and biodistribution study revealed no significant adverse events associated with the therapeutic intervention. These findings provide evidence of both therapeutic efficacy and safety, establishing a robust basis for the pursuit of an IND application for clinical trials targeting SPG47 patients.

Machine Learning-Based Surrogate Model for Genetic Algorithm with Aggressive Mutation for Feature Selection

The genetic algorithm with aggressive mutations GAAM, is a specialised algorithm for feature selection. This algorithm is dedicated to the selection of a small number of features and allows the user to specify the maximum number of features desired. A major obstacle to the use of this algorithm is its high computational cost, which increases significantly with the number of dimensions to be retained. To solve this problem, we introduce a surrogate model based on machine learning, which reduces the number of evaluations of the fitness function by an average of 48% on the datasets tested, using the standard parameters specified in the original paper. Additionally, we experimentally demonstrate that eliminating the crossover step in the original algorithm does not result in any visible changes in the algorithm’s results. We also demonstrate that the original algorithm uses an artificially complex mutation method that could be replaced by a simpler method without loss of efficiency. The sum of the improvements resulted in an average reduction of 53% in the number of evaluations of the fitness functions. Finally, we have shown that these outcomes apply to parameters beyond those utilized in the initial article, while still achieving a comparable decrease in the count of evaluation function calls. Tests were conducted on 9 datasets of varying dimensions, using two different classifiers.

Characterization of Shy1, the Schizosaccharomyces pombe homolog of human SURF1

Cytochrome c oxidase (complex IV) is the terminal enzyme in the mitochondrial respiratory chain. As a rare neurometabolic disorder caused by mutations in the human complex IV assembly factor SURF1, Leigh Syndrome (LS) is associated with complex IV deficiency. In this study, we comprehensively characterized Schizosaccharomyces pombe Shy1, the homolog of human SURF1. Bioinformatics analysis revealed that Shy1 contains a conserved SURF1 domain that links to the biogenesis of complex IV and shares high structural similarity with its homologs in Saccharomyces cerevisiae and humans. Our study showed that Shy1 is required for the expression of mtDNA-encoded genes and physically interacts with structural subunits and assembly factors of complex IV. Interestingly, Rip1, the subunit of ubiquinone-cytochrome c oxidoreductase or cytochrome bc1 complex (complex III), can also co-immunoprecipitate with Shy1, suggesting Shy1 may be involved in the assembly of the mitochondrial respiratory chain supercomplexes. This conclusion is further corroborated by our BN-PAGE analysis. Unlike its homologs, deletion of shy1 does not critically disrupt respiratory chain assembly, indicating the presence of the compensatory mechanism(s) within S. pombe that ensure mitochondrial functionality. Collectively, our investigation elucidates that Shy1 plays a pivotal role in the sustainability of the regular function of mitochondria by participating in the assembly of complex IV in S. pombe.

The catalogue of Mycobacterium tuberculosis mutations associated with drug resistance to 12 drugs in China from a nationwide survey: a genomic analysis

WHO issued the first edition catalogue of Mycobacterium tuberculosis complex (MTBC) mutations associated with drug resistance in 2021. However, country-specific issues might lead to arising complex and additional drug-resistant mutations. We aimed to fully reflect the characteristics of drug resistance mutations in China. We analysed MTBC isolates from the nationwide drug-resistant tuberculosis surveillance with 70counties in 31provinces, municipalities, and autonomous regions in China. Three types of MYCOTB plates were used to perform drug susceptibility testing for 12antibiotics (rifampicin, isoniazid, ethambutol, levofloxacin, moxifloxacin, amikacin, kanamycin, ethionamide, clofazimine, linezolid, delamanid, and bedaquiline). Mutations were divided into five groups according to their odds ratios, positive predictive values, false discovery rate-corrected p values, and 95% CIs: (1) associated with resistance; (2) associated with resistance-interim; (3) uncertain significance; (4) not associated with resistance-interim; and (5) not associated with resistance. The Wilcoxon rank-sum and Kruskal-Wallis tests were used to quantify the association between mutations and minimum inhibitory concentrations (MICs). Our dataset was compared with the first edition of the WHO catalogue. We analysed 10 146MTBC isolates, of which 9071 (89·4%) isolates were included in the final analysis. 744(8·2%) isolates were resistant to rifampicin and 1339 (14·8%) to isoniazid. 208 (1·9%) of 11 065mutations were classified as associated with resistance or associated with resistance-interim. 33 (97·1%) of 34mutations in group 1and 92 (52·9%) of 174in group 2also appeared in groups 1or 2of the WHO catalogue. Of 81indel mutations in group 2, 15 (18·5%) were in the WHO catalogue. The newly discovered mutation gyrA_Ala288Asp was associated with levofloxacin resistance. MIC values for rifampicin, isoniazid, moxifloxacin, and levofloxacin corresponding to resistance mutations in group 1were significantly different (p<0·0001), and 12 high-level resistance mutations were detected. 61mutations in group 3occurred as solo in at least five phenotypically susceptible isolates, but with MIC values moderately higher than other susceptible isolates. Among 945phenotypically resistant but genotypically susceptible isolates, 433 (45·8%) were mutated for at least one efflux pump gene. Our analysis reflects the complexity of drug resistance mutations in China and suggests that indel mutations, efflux pump genes, protein structure, and MICs should be fully considered in the WHO catalogue, especially in countries with a high tuberculosis burden. National Key Research and Development Program of China and the Science and Technology Major Project of Tibetan Autonomous Region of China.

You Don't Always Get What You Want!

Mutations in several genes of Caenorhabditis elegans confer altered sensitivities to volatile anesthetics. A mutation in one gene, gas-1(fc21), causes animals to be immobilized at lower concentrations of all volatile anesthetics than in the wild type, and it does not depend on mutations in other genes to control anesthetic sensitivity. gas-1 confers different sensitivities to stereoisomers of isoflurane, and thus may be a direct target for volatile anesthetics. The authors have cloned and characterized the gas gene and the mutant allele fc21. Genetic techniques for nematodes were as previously described. Polymerase chain reaction, sequencing, and other molecular biology techniques were performed by standard methods. Mutant rescue was done by injecting DNA fragments into the gonad of mutant animals and scoring the offspring for loss of the mutant phenotype. The gas-1 gene was cloned and identified. The protein GAS-1 is a homologue of the 49-kd (IP) subunit of the mitochondrial NADH-ubiquinone-oxidoreductase (complex I of the respiratory chain). gas-1(fc21) is a missense mutation replacing a strictly conserved arginine with lysine. The function of the 49-kd (IP) subunit of complex I is unknown. The finding that mutations in complex I increase sensitivity of C. elegans to volatile anesthetics may implicate this physiologic process in the determination of anesthetic sensitivity. The hypersensitivity of animals with a mutation in the gas-1 gene may be caused by a direct anesthetic effect on a mitochondrial protein or secondary effects at other sites caused by mitochondrial dysfunction.

A Humanized Yeast Model for Studying TRAPP Complex Mutations; Proof-of-Concept Using Variants from an Individual with a TRAPPC1-Associated Neurodevelopmental Syndrome.

Variants in membrane trafficking proteins are known to cause rare disorders with severe symptoms. The highly conserved transport protein particle (TRAPP) complexes are key membrane trafficking regulators that are also involved in autophagy. Pathogenic genetic variants in specific TRAPP subunits are linked to neurological disorders, muscular dystrophies, and skeletal dysplasias. Characterizing these variants and their phenotypes is important for understanding the general and specialized roles of TRAPP subunits as well as for patient diagnosis. Patient-derived cells are not always available, which poses a limitation for the study of these diseases. Therefore, other systems, like the yeast Saccharomyces cerevisiae, can be used to dissect the mechanisms at the intracellular level underlying these disorders. The development of CRISPR/Cas9 technology in yeast has enabled a scar-less editing method that creates an efficient humanized yeast model. In this study, core yeast subunits were humanized by replacing them with their human orthologs, and TRAPPC1, TRAPPC2, TRAPPC2L, TRAPPC6A, and TRAPPC6B were found to successfully replace their yeast counterparts. This system was used for studying the first reported individual with an autosomal recessive disorder caused by biallelic TRAPPC1 variants, a girl with a severe neurodevelopmental disorder and myopathy. We show that the maternal variant (TRAPPC1 p.(Val121Alafs*3)) is non-functional while the paternal variant (TRAPPC1 p.(His22_Lys24del)) is conditional-lethal and affects secretion and non-selective autophagy in yeast. This parallels defects seen in fibroblasts derived from this individual which also showed membrane trafficking defects and altered Golgi morphology, all of which were rescued in the human system by wild-type TRAPPC1. This study suggests that humanized yeast can be an efficient means to study TRAPP subunit variants in the absence of human cells and can assign significance to variants of unknown significance (VUS). This study lays the foundation for characterizing further TRAPP variants through this system, rapidly contributing to disease diagnosis.

Association of mutations in Mycobacterium tuberculosis complex (MTBC) respiration chain genes with hyper-transmission

BackgroundThe respiratory chain plays a key role in the growth of Mycobacterium tuberculosis complex (MTBC). However, the exact regulatory mechanisms of this system still need to be elucidated, and only a few studies have investigated the impact of genetic mutations within the respiratory chain on MTBC transmission. This study aims to explore the impact of respiratory chain gene mutations on the global spread of MTBC.ResultsA total of 13,402 isolates of MTBC were included in this study. The majority of the isolates (n = 6,382, 47.62%) belonged to lineage 4, followed by lineage 2 (n = 5,123, 38.23%). Our findings revealed significant associations between Single Nucleotide Polymorphisms (SNPs) of specific genes and transmission clusters. These SNPs include Rv0087 (hycE, G178T), Rv1307 (atpH, C650T), Rv2195 (qcrA, G181C), Rv2196 (qcrB, G1250T), Rv3145 (nuoA, C35T), Rv3149 (nuoE, G121C), Rv3150 (nuoF, G700A), Rv3151 (nuoG, A1810G), Rv3152 (nuoH, G493A), and Rv3157 (nuoM, A1243G). Furthermore, our results showed that the SNPs of atpH C73G, atpA G271C, qcrA G181C, nuoJ G115A, nuoM G772A, and nuoN G1084T were positively correlated with cross-country transmission clades and cross-regional transmission clades.ConclusionsOur study uncovered an association between mutations in respiratory chain genes and the transmission of MTBC. This important finding provides new insights for future research and will help to further explore new mechanisms of MTBC pathogenicity. By uncovering this association, we gain a more complete understanding of the processes by which MTBC increases virulence and spread, providing potential targets and strategies for preventing and treating tuberculosis.

AML-360 Mutational Landscape and Survival Outcomes of Patients with Acute Myeloid Leukemia (AML) or Myelodysplastic Syndromes (MDS) Harboring Cohesin Complex Mutations

AML-360 Mutational Landscape and Survival Outcomes of Patients with Acute Myeloid Leukemia (AML) or Myelodysplastic Syndromes (MDS) Harboring Cohesin Complex Mutations

Mutational Landscape and Survival Outcomes of Patients with Acute Myeloid Leukemia (AML) or Myelodysplastic Syndromes (MDS) Harboring Cohesin Complex Mutations

Mutational Landscape and Survival Outcomes of Patients with Acute Myeloid Leukemia (AML) or Myelodysplastic Syndromes (MDS) Harboring Cohesin Complex Mutations

The CoREST complex is a therapeutic vulnerability in malignant peripheral nerve sheath tumors.

Malignant peripheral nerve sheath tumor (MPNST) is a highly aggressive sarcoma that may be seen in patients with neurofibromatosis type 1 (NF1) or occur sporadically. While surgery is the primary treatment for localized MPNST with a 61.9% overall survival rate, metastatic disease is often fatal due to resistance to systemic therapies which underscores the urgent need for effective treatments. MPNSTs frequently harbor inactivating driver mutations in the PRC2 epigenetic repressor complex suggesting epigenetic therapies may represent a specific vulnerability in these tumors. Here, we investigate the role of the LSD1-HDAC1-CoREST (LHC) repressor complex in mediating MPNST tumor growth and progression. Our findings demonstrate that the LHC small molecule inhibitor, corin, induces apoptosis and significantly inhibits proliferation in MPNST cells. Transcriptomic analysis of corin-treated MPNST cells demonstrates specific increases in genes associated with axonogenesis and neuronal differentiation as well as altered extracellular matrix; additionally, corin treatment is shown to inhibit MPNST invasion in vitro. These results underscore the critical role of the LHC complex in facilitating MPNST growth and progression and suggest that targeting the LHC complex represents a promising therapeutic approach for this aggressive malignancy.

A potent and selective pan-RAS inhibitor, ADT-1004, targeting complex KRAS mutations for pancreatic cancer.

90 Background: Pancreatic ductal adenocarcinoma (PDAC) is a challenging cancer with a 5-year survival rate of under 12%. More than 90% of PDAC cases involve KRAS mutations. KRASG12C inhibitors recently developed have limited use because only 3% of PDAC express this mutation, highlighting the urgent need for pan-RAS inhibitors to address the complex mutation landscape in PDAC while avoiding resistance mechanisms. We synthesized and evaluated a novel pan-RAS inhibitor, ADT-1004, in mouse tumor models transplanted with mouse PDAC cell lines or patient-derived xenografts. ADT-1004 is an orally bioavailable prodrug of ADT-007, a highly potent and selective pan-RAS inhibitor (doi.org/10.1101/2023.05.17.541233). Methods: Human and mouse PDAC cell lines were utilized to evaluate in vitro growth inhibitory potency and selectivity of ADT-007. For in vivo experiments, KPC-Luc (1 × 105) and 2838C3-Luc (1.5 × 105) PDAC cells harboring the KRASG12D mutation were injected into the pancreas of C57BL/6J mice. After one week, the mice were randomly divided into treatment groups (n = 7 per group) and received oral ADT-1004 at a dose of 40mg/kg body weight five times a week for 4 weeks. Tumor burden was assessed weekly by monitoring bioluminescence signals using the IVIS Xenogen imaging system. Four patient-derived xenografts from PDAC patients with KRASG12C, KRASG12D, KRASG12V, KRASG13Q mutations were subcutaneously implanted in NSG mice by a small incision in the right flank. A week later, when the tumors reached a size of 100mm3 mice were randomized (n=7 per group) and treated orally with 40mg/kg of ADT-1004 five times a week for 6 weeks. Body weight and tumor size were measured twice weekly. Results: ADT-007 potently and selectively inhibited the growth of human and mouse PDAC cell lines. For example, the IC50 value pf ADT-007 for KRASG12C MIA PaCA-2 PDAC cells was as low as 2 nM compared to 2500 nM for RASWT BxPC3 PDAC cells. Growth inhibition was dependent on activated RAS and associated with reduced GTP-RAS levels and MAPK/AKT signaling. ADT-1004 was well tolerated in mice at a dose up to 175 mg/kg bid orally with sustained plasma levels of ADT-007 far exceeding growth IC50 values. When administered orally at 40 mg/kg body weight, ADT-1004 displayed robust antitumor activity in mouse tumor models using patient or mouse derived PDAC cell lines with G12D, G12V, G12C, or G13Q KRAS mutations, causing significant inhibitory effects on ERK phosphorylation. Conclusions: ADT-1004 inhibited tumor growth of KRAS mutant PDA tumors by targeting activated RAS to disrupt downstream MAPK/AKT signaling. The results highlight the promise of ADT-1004 as a novel pan-RAS inhibitor and open new strategies for addressing the complex genetic landscape of PDAC and other RAS driven cancers.

Genetic heterogeneity and potential recombination across hosts of Gyrovirus galga1 in central and eastern China during 2021 to 2024

Gyrovirus galga1 (GyVg1), formerly known as AGV2, was initially identified in chickens in southern Brazil. The prevalence of GyVg1 from 2021 to 2024 in 28 out of the 63 poultry farms located in Jiangsu, Anhui, Henan, Hunan, Shandong, and Hubei provinces in eastern and central China was detected via PCR. The complete genomes of the 28 strains were sequenced and exhibited a full length of 2,376 bp. Similarity analysis of these strains did not suggest definite correlation with evolutionary branching and geographical distribution. Compared with the reference GyVg1 strains, HN2202 shared the highest similarity of 99.71% with HLJ1511 (chicken-originated) from northeastern China in 2015 to 2016. Recombination analysis revealed that AH2102 was a potential recombinant of peafowl-originated HN2019-PF1 and chicken-originated HLJ1506-2, whereas HN2304 was a recombinant of peafowl-originated HN2019-PF1 and the Hungarian ferret strain G13. Mutation site analysis of the capsid protein revealed that highly mutated regions occurred between sites 288 to 316 and 383 to 419. These results indicate that GyVg1 may have undergone an interspecies transmission, which involved complex mutations and recombination. This study may provide a reference for subsequent investigations targeting the molecular epidemiology and viral evolution of GyVg1.

Maternal age enhances purifying selection on pathogenic mutations in complex I genes of mammalian mtDNA.

Mitochondrial diseases, caused mainly by pathogenic mitochondrial DNA (mtDNA) mutations, pose major challenges due to the lack of effective treatments. Investigating the patterns of maternal transmission of mitochondrial diseases could pave the way for preventive approaches. In this study, we used DddA-derived cytosine base editors (DdCBEs) to generate two mouse models, each haboring a single pathogenic mutation in complex I genes (ND1 and ND5), replicating those found in human patients. Our findings revealed that both mutations are under strong purifying selection during maternal transmission and occur predominantly during postnatal oocyte maturation, with increased protein synthesis playing a vital role. Interestingly, we discovered that maternal age intensifies the purifying selection, suggesting that older maternal age may offer a protective effect against the transmission of deleterious mtDNA mutations, contradicting the conventional notion that maternal age correlates with increased transmitted mtDNA mutations. As collecting comprehensive clinical data is needed to understand the relationship between maternal age and transmission patterns in humans, our findings may have profound implications for reproductive counseling of mitochondrial diseases, especially those involving complex I gene mutations.

8-OxodGuo and Fapy•dG Mutagenicity in Escherichia coli Increases Significantly when They Are Part of a Tandem Lesion with 5-Formyl-2'-deoxyuridine.

Tandem lesions, which are defined by two or more contiguously damaged nucleotides, are a hallmark of ionizing radiation. Recently, tandem lesions containing 5-formyl-2'-deoxyuridine (5-fdU) flanked by a 5'-8-OxodGuo or Fapy•dG were discovered, and they are more mutagenic in human cells than the isolated lesions. In the current study, we examined replication of these tandem lesions in Escherichia coli. Bypass efficiency of both tandem lesions was reduced by 30-40% compared to the isolated lesions. Mutation frequencies (MFs) of isolated 8-OxodGuo and Fapy•dG were low, and no mutants were isolated from replication of a 5-fdU construct. The types of mutations from 8-OxodGuo were targeted G → T transversion, whereas Fapy•dG predominantly gave G → T and G deletion. 5'-8-OxodGuo-5-fdU also gave exclusively G → T mutation, which was 3-fold and 11-fold greater, without and with SOS induction, respectively, compared to that of an isolated 8-OxodGuo. In mutY/mutM cells, the MF of 8-OxodGuo and 5'-8-OxodGuo-5-fdU increased 13-fold and 7-fold, respectively. The MF of 5'-8-OxodGuo-5-fdU increased 2-fold and 3-fold in Pol II- and Pol IV-deficient cells, respectively, suggesting that these polymerases carry out largely error-free bypass. The MF of 5'- Fapy•dG-5-fdU was similar without (13 ± 1%) and with (16 ± 2%) SOS induction. Unlike the complex mutation spectrum reported earlier in human cells for 5'- Fapy•dG-5-fdU, with G → T as the major type of errors, in E. coli, the mutations were predominantly from deletion of 5-fdU. We postulate that removal of adenine-incorporated opposite 8-OxodGuo by Fpg and MutY repair proteins is partially impaired in the tandem 5'-8-OxodGuo-5-fdU, resulting in an increase in the G → T mutations, whereas a slippage mechanism may be operating in the 5'- Fapy•dG-5-fdU mutagenesis. This study showed that not only are these tandem lesions more mutagenic than the isolated lesions but they may also exhibit different types of mutations in different organisms.

Subunit-specific analysis of cohesin-mutant myeloid malignancies reveals distinct ontogeny and outcomes

Mutations in the cohesin complex components (STAG2, RAD21, SMC1A, SMC3, and PDS5B) are recurrent genetic drivers in myelodysplastic neoplasm (MDS) and acute myeloid leukemia (AML). Whether the different cohesin subunit mutations share clinical characteristics and prognostic significance is not known. We analyzed 790 cohesin-mutant patients from the Dana-Farber Cancer Institute (DFCI) and the Munich Leukemia Laboratory (MLL), 390 of which had available outcome data, and identified subunit-specific clinical, prognostic, and genetic characteristics suggestive of distinct ontogenies. We found that STAG2 mutations are acquired at MDS stage and are associated with secondary AML, adverse prognosis, and co-occurrence of secondary AML-type mutations. In contrast, mutations in RAD21, SMC1A and SMC3 share features with de novo AML with better prognosis, and co-occurrence with de novo AML-type lesions. The findings show the heterogeneous nature of cohesin complex mutations, and inform clinical and prognostic classification, as well as distinct biology of the cohesin complex.

Amino acid mutation of succinate dehydrogenase complex induced resistance to benzovindiflupyr in Magnaporthe oryzae

Magnaporthe oryzae is a rice blast pathogen that seriously threatens rice yield. Benzovindiflupyr is a succinate dehydrogenase inhibitor (SDHI) fungicide that effectively controls many crop diseases. Benzovindiflupyr has a strong inhibitory effect on M. oryzae; however, control of rice blast by benzovindiflupyr and risk of resistance to benzovindiflupyr are not well studied in this pathogen. In this study, six benzovindiflupyr-resistant strains were obtained by domestication induced in the laboratory. The MoSdhBH245D mutation was the cause of M. oryzae resistance to benzovindiflupyr, which was verified through succinate dehydrogenase (SDH) activity assays, molecular docking, and site-specific mutations. Survival fitness analysis showed no significant difference between the benzovindiflupyr-resistant and parent strains. Positive cross-resistance to benzovindiflupyr and other SDHIs and negative cross-resistance to azoxystrobin were observed. Therefore, the risk of benzovindiflupyr resistance in M. oryzae might be medium to high. It should be combined with other classes of fungicides (tebuconazole and azoxystrobin) to slow the development of resistance.

Primary cilia formation requires the Leigh syndrome-associated mitochondrial protein NDUFAF2.

Mitochondria-related neurodegenerative diseases have been implicated in the disruption of primary cilia function. Mutation in an intrinsic mitochondrial complex I component NDUFAF2 has been identified in Leigh syndrome, a severe inherited mitochondriopathy. Mutations in ARMC9, which encodes a basal body protein, cause Joubert syndrome, a ciliopathy with defects in the brain, kidney, and eye. Here, we report a mechanistic link between mitochondria metabolism and primary cilia signaling. We discovered that loss of NDUFAF2 caused both mitochondrial and ciliary defects in vitro and in vivo and identified NDUFAF2 as a binding partner for ARMC9. We also found that NDUFAF2 was both necessary and sufficient for cilia formation and that exogenous expression of NDUFAF2 rescued the ciliary and mitochondrial defects observed in cells from patients with known ARMC9 deficiency. NAD+ supplementation restored mitochondrial and ciliary dysfunction in ARMC9-deficient cells and zebrafish and ameliorated the ocular motility and motor deficits of a patient with ARMC9 deficiency. The present results provide a compelling mechanistic link, supported by evidence from human studies, between primary cilia and mitochondrial signaling. Importantly, our findings have significant implications for the development of therapeutic approaches targeting ciliopathies.

The clinical spectrum associated with ERCC5 mutations: Is there a relationship between phenotype and genotype?

AbstractMutations in the ERCC5 gene can lead to different clinical phenotypes, few articles have reported the clinical phenotypes in detail and explained the relationship between genotype and phenotype. The clinical data of cases with ERCC5 gene mutations diagnosed in our center and reported in previous studies were collected. The cases were divided into three groups based on phenotype; the differences of clinical manifestation and genotype among groups were analyzed. Genetic tests showed a complex heterozygous mutation of the ERCC5 gene with paternal C.402_C.403 (exon 4) insA (p.T135Nfs*28) and maternal C.1096 (exon 8) C &gt; T (p.R366X.821) in our case. The gene mutation has not been reported and was predicted to seriously affect the protein structure. According to a review of 59 cases of ERCC5 mutations, cerebrooculofacioskeletal syndrome (COFS) occurred in 16 cases, XP in 19 cases, and XP/CS in 24 cases. The incidence of physical retardation, mental retardation, peripheral neuropathy, magnetic resonance abnormalities and fundus/vision abnormalities in XP/CS patients was significantly higher than that in XP patients. In addition, patients with the XP/CS phenotype were more prone to appearance abnormalities, deafness, and epilepsy, and cheilitis and tumors were more common in patients with the XP phenotype, but the differences were not significant. XP/CS can cause abnormal liver function and even fatality, which should be given attention. ERCC5 mutation‐related diseases were characterized by mild to severe clinical phenotypes. In addition to tumors, liver function should be considered in ERCC5‐related diseases, and patients should be cautious with medication to avoid drug‐induced liver injury.