The General Transcription Factor TAF7 is Essential for Embryonic Development but Not Essential for the Survival or Differentiation of Mature T Cells (T cell data)

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. The T cells are purified spleen CD4+ T cells coming either from TAF7f/- 8EIII-cre+ (TAF7 -/-) or TAF7 f/- 8EIII-cre - (TAF7+/-). The cells were purified by FACS based on cell surface marker expression: high TCRbeta and CD4 expression. The cells are enriched in naive CD4 T cells based on their low level of CD44 surface expression. All RNAs were extracted using shredders and the Qiagen RNeasy mini kit and their quality assayed before using for hybridization. Total RNA 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.