Project description:We compared TET1 and TET3 overexpressing cells to uninduced cells with endogenous levels of the respective transcript to determine global gene expression changes. TET1 overexpression, TET3 overexpression
Project description:Ten-eleven translocation (Tet) hydroxylases (Tet1-3) oxidize 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC). In neurons increased 5hmC levels within gene bodies correlate positively with gene expression. The mechanisms controlling Tet activity and 5hmC levels are poorly understood. In particular, it is not known how the neuronal Tet3 isoform lacking a DNA binding domain is targeted to the DNA. To identify factors binding to Tet3 we screened for proteins that co-precipitate with Tet3 from mouse retina and identified the transcriptional repressor Rest as a highly enriched Tet3-specific interactor. Rest was able to enhance Tet3 hydroxylase activity after co-expression and overexpression of Tet3 activated transcription of Rest-target genes. Moreover, we found that Tet3 also interacts with Nsd3 and two other H3K36 methyltransferases and is able to induce H3K36 trimethylation. We propose a mechanism for transcriptional activation in neurons that involves Rest-guided targeting of Tet3 to the DNA for directed 5hmC-generation and Nsd3-mediated H3K36 trimethylation.
Project description:TET1, TET2 and TET3 are DNA demethylases with critical roles during early embryonic development and cell differentiation. To assess the contributions of TET proteins to cell function during early development, single and compound knockouts of Tet genes in mouse pluripotent embryonic stem cells (ESCs) were generated. ESCs lacking all alleles of Tet1 and Tet2, or all alleles of Tet1, Tet2 and Tet3 form epiblast-like cells and epiblast stem cells in culture, indicating that TET proteins are not required to transit between naïve, formative and primed pluripotency. Moreover, in differentiation protocols, ESCs with double-knockouts of Tet1 and Tet2 or triple-knockouts of Tet1, Tet2 and Tet3 do not differentiate normally , fail to activate somatic gene expression and retain expression of pluripotency transcription factors. Therefore, TET1 and TET2, but not TET3 act redundantly to facilitate somatic differentiation. Importantly, ESCs with double knockouts of Tet1 and Tet2, or triple knockouts of Tet1, Tet2 and Tet3 cells do differentiate into primordial germ cell-like cells (PGCLCs). Furthermore, PGCLC differentiation of Tet1, Tet2 double knockouts, or Tet1, Tet2, Tet3 triple knockouts occurs with high efficiency in the presence or absence of PGC-promoting cytokines. Moreover, acquisition of a PGCLC transcriptional programme occurs more rapidly in the absence of TET proteins. These results establish TET proteins as key regulators enabling epiblast cells to choose between somatic and germline fates. The functions of Tet1 and Tet2, but not Tet3 are required to enable epiblast cells to undergo somatic differentiation and in the absence of TET protein function, epiblast cell differentiation defaults to the germline.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.