Pluto Bioinformatics

GSE76552: Abnormal X chromosome inactivation and sex-specific gene dysregulation after ablation of FBXL10

Bulk RNA sequencing

The FBXL10 protein (also known as KDM2B, JHDM1B, CXXC2, and NDY1) is bound to essentially all CpG-rich promoters in the mammalian genome. FBXL10 is expressed as two isoforms: FBXL10-1, a longer form that contains an N-terminal JmjC domain with C- terminal F-box, CXXC, PHD, RING, and leucine rich repeat (LRR) domains, and FBXL10-2, a shorter form that initiates at an alternative internal exon and which lacks the JmjC domain but retains the other domains. Selective deletion of Fbxl10-1 had been reported to produce a minor and variable phenotype, and most mutant animals were essentially normal. We show here that deletion of Fbxl10-2 (in a manner that does not perturb expression of Fbxl10-1) resulted in a very different phenotype with craniofacial abnormalities, greatly increased lethality, and female sterility in surviving homozygous mutants. The phenotype of the Fbxl10-2 deletion was more severe in female mutants. We found that mutants that lacked both FBXL10-1 and -2 showed embryonic lethality and even more extreme sexual dimorphism, with more severe gene dysregulation in mutant female embryos. X-linked genes were most severely dysregulated, and there was marked overexpression of Xist in mutant females although genes that encode factors that bind to Xist RNA were globally down-regulated in mutant female as compared to male embryos. FBXL10 is the first factor shown to be required both for the normal expression and function of the Xist gene. SOURCE: John,R.,Edwards (jedwards@dom.wustl.edu) - Washington University School of Medicine