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Genetic factors are one of the most important causes of non-obstructive azoospermia (NOA). ESX1 is an X-linked testis-biased expressed gene, and a potential biomarker for testicular sperm retrieval in NOA patients, yet few systematic studies have investigated its association with NOA. Here, we performed selected exonic sequencing in a large cohort of Chinese males, and four novel missense mutations (including one compound mutation), one novel synonymous mutation of ESX1 unique to NOA patients were identified. We analyzed the effects of ESX1 mutations on cyclin A degradation and cell cycle progression by immunoprecipitation assay and flow cytometry, and found that the compound mutant p.[P365R; L366V] ESX1 compromised the stabilizing effect of ESX1 on polyubiquitinated cyclin A, thereby causing the failure of M phase arrest in cells. Further studies showed that the deleterious effect of the compound mutations on ESX1 protein function was attributed to p.P365R but not p.L366V alteration. The novel ESX1 mutation p.P365R might confer high risk for NOA in Han Chinese population, probably via affecting cell cycle control. [ABSTRACT FROM AUTHOR]

Although more than 1,000 androgen receptor (AR) mutations have been identified and these mutants are pathologically important, few theoretical studies have investigated the role of AR protein folding stability in disease and its relationship with the phenotype of the patients. Here, we extracted AR variant data from four databases: ARDB, HGMD, Cosmic, and 1,000 genome. 905 androgen insensitivity syndrome (AIS)-associated loss-of-function mutants and 168 prostate cancer-associated gain-of-function mutants in AR were found. We analyzed the effect of single-residue variation on the folding stability of AR by FoldX and guanidine hydrochloride denaturation experiment, and found that genetic disease-associated mutations tend to have a significantly greater effect on protein stability than gene polymorphisms. Moreover, AR mutants in complete androgen insensitivity syndrome (CAIS) tend to have a greater effect on protein stability than in partial androgen insensitive syndrome (PAIS). This study, by linking disease phenotypes to changes in AR stability, demonstrates the importance of protein stability in the pathogenesis of hereditary disease. [ABSTRACT FROM AUTHOR]