Project description:We have uncovered that BEND3 is a heterochromatin-associated protein that functions as a transcription repressor. Expression of BEND3 correlates with the state of pluripotency, with a significant decline in BEND3 levels in differentiated cells. Cells lacking BEND3 show defects in cell cycle progression with failure to enter S-phase. BEND3 affects the transcription of cellular genes that modulate chromatin organization and cellular differentiation and that downregulation of BEND3 is critical for cellular differentiation.
Project description:We have uncovered that BEND3 is a heterochromatin-associated protein that functions as a transcription repressor. Expression of BEND3 correlates with the state of pluripotency, with a significant decline in BEND3 levels in differentiated cells. Cells lacking BEND3 show defects in cell cycle progression with failure to enter S-phase. BEND3 affects the transcription of cellular genes that modulate chromatin organization and cellular differentiation and that downregulation of BEND3 is critical for cellular differentiation.
Project description:TGF-beta/Smads signaling plays important roles in vascular integrity. To identify potential Smad4 target genes in brain endothelial cells that control cerebrovascular integrity, the microarray assay was performed to compare the gene expression profiles of bEnd3 transfected with Smad4-siRNA and control-siRNA. bEnd3 cells were infected by Smad4-siRNA or control-siRNA retrovirus particles produced by PLAT-E packaging cells and selected by puromycin. The specific and control RNAi cells were used for RNA extraction and hybridization on Affymetrix microarrays. Two independent infections were performed and samples were pooled in order to obtain representative populations.
Project description:TGF-beta/Smads signaling plays important roles in vascular integrity. To identify potential Smad4 target genes in brain endothelial cells that control cerebrovascular integrity, the microarray assay was performed to compare the gene expression profiles of bEnd3 transfected with Smad4-siRNA and control-siRNA.
Project description:Epigenetic mechanisms are essential to establish and safeguard cellular identities in mammals. They dynamically regulate the expression of genes, transposable elements and higher-order chromatin structures. Consequently, these chromatin marks are indispensable for mammalian development and alterations often lead to disease, such as cancer. Bivalent promoters are especially important during differentiation and development. Here we used a genetic screen to identify new regulators of a bivalent repressed gene. We identify BEND3 as a regulator of hundreds of bivalent promoters, some of which it represses, and some of which it activates. We show that BEND3 is recruited to a CpG-containg consensus site that is present in multiple copies in many bivalent promoters. Besides having direct effect on the promoters it binds, the loss of BEND3 leads to genome-wide gains of DNA methylation, which are especially marked at regions normally protected by the TET enzymes. DNA hydroxymethylation is reduced in Bend3 mutant cells, possibly as consequence of altered gene expression leading to diminished alpha-ketoglutarate production, thus lowering TET activity. Our results clarify the direct and indirect roles of an important chromatin regulator, BEND3, and, more broadly, they shed light on the regulation of bivalent promoters.