BioProject

TAF7, a component of the TFIID complex that nucleates the assembly of transcription preinitiation complexes, also independently interacts with and regulates the enzymatic activities of other transcription factors, including P-TEFb, TFIIH and CIITA, ensuring an orderly progression in transcription initiation. More...

TAF7, a component of the TFIID complex that nucleates the assembly of transcription preinitiation complexes, also independently interacts with and regulates the enzymatic activities of other transcription factors, including P-TEFb, TFIIH and CIITA, ensuring an orderly progression in transcription initiation. Since not all TAFs are required in terminally differentiated cells, we examined the essentiality of TAF7 in cells at different developmental stages in vivo. Germ-line disruption of the TAF7 gene is embryonic lethal between 3.5 and 5.5 days post coitus. TAF7-deleted mouse embryonic fibroblasts (MEFs) globally cease transcription and stop proliferating. In contrast, whereas TAF7 is essential for the differentiation and proliferation of immature thymocytes, it is not required for subsequent, proliferation-independent differentiation of lineage committed thymocytes or their egress into the periphery. TAF7 deletion in peripheral CD4+ T cells affects only a small number of transcripts. However, TAF7-deleted T cells are not able to undergo activation and expansion in response to antigenic stimuli. These findings suggest that TAF7 is essential for proliferation but not for proliferation-independent differentiation. Overall design: We previously provided evidence that TAF7 is a regulator of the early steps of transcription initiation, that it affects the expression of about 65% of transcripts in 293 kidney cells, and of those, some are TAF1-dependent while others are TAF1-independent. Therefore, we next asked whether TAF7 is dispensable for a subset of embryonic fibroblast genes or whether it is required globally. Both TAF7f/f and TAF7+/+ MEF lines were infected by MSCV Cre-GFP retroviruses, and the infected cells (GFP+) were isolated by FACS at 24, 48 and 72 hours post infection. Uninfected cells from each line were harvested at the same time, collected by FACS and processed simultaneously to be used as controls. The experiments were performed in triplicate. All RNAs were extracted using shredders and the Qiagen RNeasy mini kit and their quality assayed before using for hybridization. Total RNA from each of the triplicates was hybridized on the Affymetrix exon array. All exon array data were analyzed with Affymetrix Expression Console SoftwareTM (version 1.1). The Robust Multi-array Analysis (RMA) algorithm was used for gene intensity analysis. Only genes in the “core” set, which represents RefSeq and full-length GenBank mRNAs, were included in the analysis. Less...