Project description:CTCFL binding to DNA and the effect of CTCFL expression in ES cells RNA extracted from CTCFL induced and non-induced ES cells was hybridized on Affymetrix Mouse Gene 1.0ST arrays
Project description:Ctcfl, a paralog of Ctcf, also known as BORIS (Brother of Regulator of Imprinted Sites), is a testis expressed gene whose function is largely unknown. As a cancer testis antigen, it is often expressed in tumor cells and also seen in two benign human vascular malformations, juvenile angiofibromas (JA) and infantile hemangiomas (IH). To better understand the function of Ctcfl we created tetracycline-inducible Ctcfl transgenic mice. We show that when Ctcfl expression is induced during embryogenesis, it results in intrauterine growth retardation, developmental eye malformations, multi-organ pathologies, vascular defects, and early neonatal lethality. This phenotype resembles prior mouse models which perturb the TGFB pathway. Embryonic stem cells with the Ctcfl transgene reproduce the same phenotype in ES cell: tetraploid chimeras. RNA-Seq of the Ctcfl ES cells revealed 14 genes, including a number of transcription factors/ co-activators, and signal transduction pathway genes that are significantly deregulated by Ctcfl expression. Bioinformatics analysis revealed the TGFB pathway to be most affected by embryonic Ctcfl expression. We propose that our transgenic mice reiterate a developmental program normally reserved for spermatogenesis that results in multiple organ pathology when expressed in embryogenesis as a result of the TGFB pathway dysregulation. Understanding of the phenotypic consequence of Ctcfl expression in non-testicular cells and elucidating downstream targets of Ctcfl has the potential to explain its role as a cancer testis antigen (CTA) and its involvement in two, if not more, human vascular malformations.
Project description:CTCF and CTCFL DNA binding profile in CTCFL induced and non-induced ES cells.CTCF is a highly conserved and essential zinc finger protein that in conjunction with cohesin organizes chromatin into loops, thereby regulating gene expression and epigenetic events. The function of CTCFL or BORIS, the testis-specific paralogue of CTCF, is less clear. Here, we show that CTCFL is only transiently present during spermatogenesis, prior to the onset of meiosis, when the protein co-localizes in nuclei with ubiquitously expressed CTCF. Our data show that CTCFL is functionally different from CTCF and its absence in mice causes sub-fertility due to a partially penetrant testicular atrophy. Genome-wide studies reveal that CTCFL and CTCF bind similar consensus sequences. However, only ~2000 out of the ~5,700 CTCFL and ~31,000 CTCF binding sites overlap. CTCFL binds promoters with loosely assembled nucleosomes, whereas CTCF favors consensus sites surrounded by phased nucleosomes. Thus, nucleosome dynamics specifies the genome-wide binding of CTCFL and CTCF. We propose that the transient expression of CTCFL in spermatogonia and preleptotene spermatocytes serves to occupy a subset of promoters and maintain the expression of male germ cell genes ChIP-seq for CTCF (with CTCF antibody) and CTCFL (with V5 antibody) in CTCFL_V5_GFP induced and non-induced ES cells