Project description:Dosage imbalance for X-chromosomal genes contributes to sex differences, in particular during early development, when both X chromosomes are active in females. X-encoded inhibitors of the differentiation-promoting MAP kinase (MAPK) signalling pathway slow down development, increase levels of naive pluripotency factors, and decrease MAPK target gene expression. Through a hierarchical CRISPR screening approach in murine embryonic stem cells(mESC) we have comprehensively identified X-linked genes that modulate MAPK signalling, pluripotency factor expression, and differentiation. Here, we carried out transcriptional profiling of the two top hits, Dusp9 and Klhl13, and observe that Klhl13 contributes more to the X-dosage induced transcriptome changes than Dusp9, and that a combined effect of both can explain about 50% of the observed sex differences.
Project description:Developmental genes are controlled by complex cis-regulatory landscapes that integrate multiple signals to ensure the correct spatio-temporal expression pattern. To investigate the underlying regulatory principles, we use the Xist locus as a model, which encodes the master regulator of X-chromosome inactivation. Xist is upregulated at the primed pluripotent state in a female-specific manner, thus integrating developmental cues and X-dosage information. It remains poorly understood how these signals are decoded by the ~800kb genomic region that controls Xist. While a series of repressive cis-regulatory elements have been identified, the distal enhancers that activate Xist transcription remain largely unknown. Here we use STARR-seq to profile enhancer activity within the X inactivation center at the onset of random X-chromosome inactivation.
Project description:As the master regulator of X-chromosome inactivation (XCI), the Xist RNA is expressed nearly ubiquitously in female mice. Xist is only absent in the germ line and at the pluripotent state. Xist is generally assumed to be expressed “by default” in females, while being actively repressed in the few tissues where it is silent. Whether activating mechanisms also contribute remained largely unknown. Through a pooled CRISPR screen we identify the GATA family of transcription factors as potent direct activators of Xist. We describe a GATA-responsive regulatory element (RE79), located ~100 kb upstream of the Xist promoter. In cell lines derived from the two extraembryonic lineages, XEN and TS cells, where imprinted Xist expression is maintained, RE79 is bound by different sets of GATA factors expressed in those tissues. Here we use RNA-seq on differentiating XO mouse embryonic stem cells as a reference for gene expression during early differentiation.
Project description:Developmental genes are controlled by complex cis-regulatory landscapes that integrate multiple signals to ensure the correct spatio-temporal expression pattern. To investigate the underlying regulatory principles, we use the Xist locus as a model, which encodes the master regulator of X-chromosome inactivation. Xist is upregulated at the primed pluripotent state in a female-specific manner, thus integrating developmental cues and X-dosage information. It remains poorly understood how these signals are decoded by the ~800kb genomic region that controls Xist. While a series of repressive cis-regulatory elements have been identified, the distal enhancers that activate Xist transcription remain largely unknown. Here we use ATAC-seq to profile DNA accessibility within the X inactivation center at the onset of random X-chromosome inactivation using an endogenous cell model of the inactive (TX 1072 XXΔXic) and active (TX 1072 XO) X chromosome.
Project description:Dosage imbalance for X-chromosomal genes contributes to sex differences, in particular during early development, when both X chromosomes are active in females. X-encoded inhibitors of the differentiation-promoting MAP kinase (MAPK) signalling pathway slow down development, increase levels of naive pluripotency factors, and decrease MAPK target gene expression. Through a hierarchical CRISPR screening approach in murine embryonic stem cells(mESC) we have comprehensively identified X-linked genes that modulate MAPK signalling, pluripotency factor expression, and differentiation. Here, we carried out transcriptional profiling of the two top hits, Dusp9 and Klhl13, and observe that Klhl13 contributes more to the X-dosage induced transcriptome changes than Dusp9, and that a combined effect of both can explain about 50% of the observed sex differences.