Project description:Due to the variable presentation of mosaic chromosomal abnormalities, cases such as this are needed to define the phenotypic spectrum. It also highlights the importance of chromosome analysis to identify structural abnormalities that result in aneuploidy.
Project description:Somatic mutations of the cohesin complex subunit STAG2 are present in diverse tumor types. We and others have shown that STAG2 inactivation can lead to loss of sister chromatid cohesion and alterations in chromosome copy number in experimental systems. However, studies of naturally occurring human tumors have demonstrated little, if any, correlation between STAG2 mutational status and aneuploidy, and have further shown that STAG2-deficient tumors are often euploid. In an effort to provide insight into these discrepancies, here we analyze the effect of tumor-derived STAG2 mutations on the protein composition of cohesin and the expected mitotic phenotypes of STAG2 mutation. We find that many mutant STAG2 proteins retain their ability to interact with cohesin; however, the presence of mutant STAG2 resulted in a reduction in the ability of regulatory subunits WAPL, PDS5A, and PDS5B to interact with the core cohesin ring. Using AAV-mediated gene targeting, we then introduced nine tumor-derived mutations into the endogenous allele of STAG2 in cultured human cells. While all nonsense mutations led to defects in sister chromatid cohesion and a subset induced anaphase defects, missense mutations behaved like wild-type in these assays. Furthermore, only one of nine tumor-derived mutations tested induced overt alterations in chromosome counts. These data indicate that not all tumor-derived STAG2 mutations confer defects in cohesion, chromosome segregation, and ploidy, suggesting that there are likely to be other functional effects of STAG2 inactivation in human cancer cells that are relevant to cancer pathogenesis.
Project description:We report on a fragile X mosaic male full mutation/normal allele detected by PCR and methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA). This combined analysis provides a diagnostic approach for fragile X syndrome (FXS). The method assesses the presence of expansion (full mutation), the CpG methylation status and could determine copy number changes (large deletions/duplications) along the FMR1 and FMR2 (fragile X mental retardation) genes. The method avoids detection of premutations, which makes it applicable for newborn screening. It can also be used in clarification of mosaic cases. The PCR results in our patient showed one normal allele; three repeats larger than his mother's one. The MS-MLPA showed hypermethylated full mutation pattern in the proband. Both results are compatible with FXS mosaic case full mutation/normal allele. The patient demonstrates atypical mild clinical manifestation of the disease, which correlates to the presence of a normal size allele in the patient's cells.
Project description:BACKGROUND:Infertility is a health problem which affects about 10-20% of married couples. Male factor infertility is involved approximately 50% of infertile couples. Most of male infertility is regarding to deletions in the male-specific region of the Y chromosome. OBJECTIVE:In this study, the occurrence of deletions in the AZF region and association between infertility and paternal age were investigated in Iranian men population. MATERIALS AND METHODS:To assess the occurrence of Y chromosomal microdeletions and partial deletions of the AZF region, 100 infertile men and 100 controls with normal spermatogenesis were analyzed. AZFa, AZFb, AZFc and partial deletions within the AZFc region were analyzed using multiplex PCR method. Finally, the association between paternal age and male infertility was evaluated. RESULTS:No AZFa, AZFb or AZFc deletions were found in the control group. Seven infertile men had deletions as the following: one AZFb, five AZFc, and one AZFab. Partial deletions of AZFc (gr/gr) in 9 of the 100 infertile men (9/100, 9%) and 1 partial AZFc deletions (gr/gr) in the control group (1/100, 1%) were observed. In addition, five b2/b3 deletions in five azoospermic subjects (5/100, 5%) and 2 partial AZFc deletions (b2/b3) in the control group (2/100, 2%) were identified. Moreover, the risk of male infertility was influenced by the paternal age. CONCLUSION:The results of this study suggested that the frequency of Y chromosome AZF microdeletions increased in subjects with severe spermatogenic failure and gr/gr deletion associated with spermatogenic failure.
Project description:We present a 2-year-old boy with a de novo 46,XY,idic(Y)(q11.221),del(4)(q26q31.1) karyotype. G-banding, FISH, MLPA, and SNP-array techniques were used to characterize the 24-Mb deletion in 4q and the breakpoint in the isodicentric Y-chromosome region between 15,982,252 and 15,989,842 bp. The patient presented with mild facial dysmorphism, hemangioma, mild frontal cerebral atrophy, and Dandy-Walker variant. Essentially, this case reveals that patients can present more complex genomic imbalances than initially suspected.
Project description:BackgroundGlyphosate is the most commonly used herbicide worldwide and has been implicated in the development of certain hematologic cancers. Although mechanistic studies in human cells and animals support the genotoxic effects of glyphosate, evidence in human populations is scarce.ObjectivesWe evaluated the association between lifetime occupational glyphosate use and mosaic loss of chromosome Y (mLOY) as a marker of genotoxicity among male farmers.MethodsWe analyzed blood-derived DNA from 1,606 farmers ≥50 years of age in the Biomarkers of Exposure and Effect in Agriculture study, a subcohort of the Agricultural Health Study. mLOY was detected using genotyping array intensity data in the pseudoautosomal region of the sex chromosomes. Cumulative lifetime glyphosate use was assessed using self-reported pesticide exposure histories. Using multivariable logistic regression, we estimated odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between glyphosate use and any detectable mLOY (overall mLOY) or mLOY affecting ≥10% of cells (expanded mLOY).ResultsOverall, mLOY was detected in 21.4% of farmers, and 9.8% of all farmers had expanded mLOY. Increasing total lifetime days of glyphosate use was associated with expanded mLOY [highest vs. lowest quartile; OR=1.75 (95% CI: 1.00, 3.07), ptrend=0.03] but not with overall mLOY; the associations with expanded mLOY were most apparent among older (≥70 years of age) men [OR=2.30 (95% CI: 1.13, 4.67), ptrend=0.01], never smokers [OR=2.32 (95% CI: 1.04, 5.21), ptrend=0.04], and nonobese men [OR=2.04 (95% CI: 0.99, 4.19), ptrend=0.03]. Similar patterns of associations were observed for intensity-weighted lifetime days of glyphosate use.DiscussionHigh lifetime glyphosate use could be associated with mLOY affecting a larger fraction of cells, suggesting glyphosate could confer genotoxic or selective effects relevant for clonal expansion. As the first study to investigate this association, our findings contribute novel evidence regarding the carcinogenic potential of glyphosate and require replication in future studies. https://doi.org/10.1289/EHP12834.
Project description:Soil-borne wheat mosaic virus (SBWMV) causes a serious viral disease that can significantly reduce grain yield in winter wheat worldwide. Using resistant cultivars is the only feasible strategy to reduce the losses caused by SBWMV. To fine map the resistance gene Sbwm1, 205 wheat accessions was genotyped using wheat Infinium iSelect Beadchips with 90?K SNPs. Association analysis identified 35 SNPs in 12 wheat genes and one intergenic SNP in the Sbwm1 region that showed a significant association with SBWMV resistance. Those SNPs were converted into Kompetitive Allele-Specific Polymerase assays (KASP) and analyzed in two F6-derived recombinant inbred line (RIL) populations derived from the crosses between two resistant cultivars 'Wesley' and 'Deliver' and a susceptible line 'OK03825-5403-6'. Linkage analysis mapped this gene on chromosome 5D at intervals of 5.1?cM and 3.4?cM in the two populations, respectively. The two flanking markers in both populations delimited the gene to a 620?kb region where 19 genes were annotated. Comparative analysis identified a syntenic region of 660?kb in Ae. tauschii with 18 annotated genes and a syntenic region in chromosome 1 of B. distachyon. The candidate region includes several disease resistance related genes and we identified a PTI1-like tyrosine-protein kinase 1 gene as a putative candidate gene for Sbwm1. The two flanking SNPs for Sbwm1 can effectively separate the resistant and susceptible lines in a new diversity panel of 159 wheat germplasm. The results from this study lay a solid foundation for the cloning, functional characterization and marker-assisted selection of Sbwm1.
Project description:The haploid liverwort Marchantia polymorpha has heteromorphic sex chromosomes, an X chromosome in the female and a Y chromosome in the male. We here report on the repetitive structure of the liverwort Y chromosome through the analysis of male-specific P1-derived artificial chromosome (PAC) clones, pMM4G7 and pMM23-130F12. Several chromosome-specific sequence elements of approximately 70 to 400 nt are combined into larger arrangements, which in turn are assembled into extensive Y chromosome-specific stretches. These repeat sequences contribute 2-3 Mb to the Y chromosome based on the observations of three different approaches: fluorescence in situ hybridization, dot blot hybridization, and the frequency of clones containing the repeat sequences in the genomic library. A novel Y chromosome-specific gene family was found embedded among these repeat sequences. This gene family encodes a putative protein with a RING finger motif and is expressed specifically in male sexual organs. To our knowledge, there have been no other reports for an active Y chromosome-specific gene in plants. The chromosome-specific repeat sequences possibly contribute to determining the identity of the Y chromosome in M. polymorpha as well as to maintaining genes required for male functions, as in mammals such as human.
Project description:Amplificaition of HOXD9 and HOXD13 genes was found in MWCNTs induced carcinogencity. By overexpression or silence of of HOXD9 and HOXD13 gene may alter tumorigenicity. To investigate the realted signaling pathways invovled in HOXD regulated tumorigencity, we analyzed the gene expression profile of the HOXD9 or HOXD13 overexpression HEK293 cells, which compared to vehicle expressing cells
Project description:The complete sequence of the male-specific region of the human Y chromosome (MSY) has been determined recently; however, detailed characterization for many of its encoded proteins still remains to be done. We applied state-of-the-art protein structure prediction methods to all 27 distinct MSY-encoded proteins to provide better understanding of their biological functions and their mechanisms of action at the molecular level. The results of such large-scale structure-functional annotation provide a comprehensive view of the MSY proteome, shedding light on MSY-related processes. We found that, in total, at least 60 domains are encoded by 27 distinct MSY genes, of which 42 (70%) were reliably mapped to currently known structures. The most challenging predictions include the unexpected but confident 3D structure assignments for three domains identified here encoded by the USP9Y, UTY, and BPY2 genes. The domains with unknown 3D structures that are not predictable with currently available theoretical methods are established as primary targets for crystallographic or NMR studies. The data presented here set up the basis for additional scientific discoveries in human biology of the Y chromosome, which plays a fundamental role in sex determination.