Project description:Dysfunction of the dystrophin-glycoprotein complex (DGC) is a frequent cause of hereditary forms of muscular dystrophy. Although DGC function in maintaining skeletal muscle integrity has been well characterized, little is known about how the DGC complex is coordinately regulated at the transcriptional level. To test this hypothesis, we engineered HDAC4 stably overexpressing and control myotubes in an in vitro model of muscle differentiation. Here we present evidence that HDAC4, a neural activity-responsive histone deacetylase, is a critical transcriptional regulator of the DGC complex. We show that HDAC4 can repress multiple components of the DGC complex, including dystrophin and sarcoglycan family members in both cultured myotubes. To confirm this finding, the protein levels of core DGC complex members including dystrophin, sarcoglycan complex members, and additional dystrophin-associated proteins were evaluated in differentiated myotubes by western analysis. C2C12 mouse myotubes were infected with either a HDAC4 expressing or control (Neo) retroviruses. After stable selection, myotubes were differentiated at 90% confluency in 2% horse serum (Hyclone) for 4 days. At this time point, RNA was extracted and the two types of cells compared in a microarray analysis.
Project description:Dysfunction of the dystrophin-glycoprotein complex (DGC) is a frequent cause of hereditary forms of muscular dystrophy. Although DGC function in maintaining skeletal muscle integrity has been well characterized, little is known about how the DGC complex is coordinately regulated at the transcriptional level. To test this hypothesis, we engineered HDAC4 stably overexpressing and control myotubes in an in vitro model of muscle differentiation. Here we present evidence that HDAC4, a neural activity-responsive histone deacetylase, is a critical transcriptional regulator of the DGC complex. We show that HDAC4 can repress multiple components of the DGC complex, including dystrophin and sarcoglycan family members in both cultured myotubes. To confirm this finding, the protein levels of core DGC complex members including dystrophin, sarcoglycan complex members, and additional dystrophin-associated proteins were evaluated in differentiated myotubes by western analysis. Keywords: genetic modification and cell type comparison of muscle cells
Project description:To characterize the genetic basis of hybrid male sterility in detail, we used a systems genetics approach, integrating mapping of gene expression traits with sterility phenotypes and QTL. We measured genome-wide testis expression in 305 male F2s from a cross between wild-derived inbred strains of M. musculus musculus and M. m. domesticus. We identified several thousand cis- and trans-acting QTL contributing to expression variation (eQTL). Many trans eQTL cluster into eleven ‘hotspots,’ seven of which co-localize with QTL for sterility phenotypes identified in the cross. The number and clustering of trans eQTL - but not cis eQTL - were substantially lower when mapping was restricted to a ‘fertile’ subset of mice, providing evidence that trans eQTL hotspots are related to sterility. Functional annotation of transcripts with eQTL provides insights into the biological processes disrupted by sterility loci and guides prioritization of candidate genes. Using a conditional mapping approach, we identified eQTL dependent on interactions between loci, revealing a complex system of epistasis. Our results illuminate established patterns, including the role of the X chromosome in hybrid sterility.
Project description:The replication timing program, or the order in which DNA is duplicated during S-phase, is associated with various features of chromosome structure and function, including gene expression, histone modifications, and 3-D compartmentalization of chromatin.
Project description:We collected whole genome testis expression data from hybrid zone mice. We integrated GWAS mapping of testis expression traits and low testis weight to gain insight into the genetic basis of hybrid male sterility.
