Project description:DNA methylation mediated epigenetic regulation plays a critical role in regulating cardiomyocytes (CM) differentiation. Tet protein mediated DNA methylation oxidation have been reported to play an important role in regulating embryonic stem cell (ESC) differentiation toward different lineages. In our study, we utilized CRISPR/Cas9 based genome editing method to generated Tet single, double and triple deficient mouse ESC (mESC) expressing emGFP under NKX2.5 promoter and differentiated these cells toward CM progenitors. By modulating emGFP population as cardiac progenitor cells, we found that deletion of Tet1 and Tet2 significantly impairs mESC differentiation toward CM progenitors. Further single-cell RNA-seq analysis in differentiated control and Tet-triple knockout (TKO) mESC reveals that Tet deletion resulted in accumulation of mesoderm progenitors and impairs CM differentiation. Overexpression the catalytic domain of Tet1 could rescue the development defects in Tet-TKO mESC and restore NKX2.5 gene expression. In addition, loci-specific dCas9-Tet1CD mediated epigenome editing at Hand1 loci confirmed its directly transcriptional regulation during CM differentiation. Overall, out studies suggested that Tet protein mediated epigenomic remodeling is a genome-wide event and is essential to maintain proper transcription network during mESC differentiation toward CM progenitors.
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.
