Keywords :
Animals; Autocrine Communication/drug effects/genetics; Base Sequence; COS Cells; Cell Proliferation/drug effects; Cells, Cultured; Cercopithecus aethiops; Connective Tissue Growth Factor; Consensus Sequence; Fibroblasts/drug effects/physiology; Gene Expression Profiling; Gene Expression Regulation/drug effects; Immediate-Early Proteins/genetics; Intercellular Signaling Peptides and Proteins/genetics; Mice; Receptor Cross-Talk/drug effects; Receptors, Retinoic Acid/metabolism; Response Elements; Transcription Factor TFIID/genetics/metabolism/physiology; Transforming Growth Factor beta/genetics/physiology; Tretinoin/pharmacology
Abstract :
[en] To evaluate the role of murine TFIID subunit TAF4 in activation of cellular genes by all-trans retinoic acid (T-RA), we have characterized the T-RA response of taf4(lox/-) and taf4(-/-) embryonic fibroblasts. T-RA regulates almost 1000 genes in taf4(lox/-) cells, but less than 300 in taf4(-/-) cells showing that TAF4 is required for T-RA regulation of most, but not all cellular genes. We further show that T-RA-treated taf4(lox/-) cells exhibit transforming growth factor (TGF)beta-dependent autocrine growth and identify a set of genes regulated by loss of TAF4 and by T-RA corresponding to key mediators of the TGFbeta signalling pathway. T-RA rapidly and potently induces expression of connective tissue growth factor (CTGF) via a conserved DR2 type response element in its proximal promoter leading to serum-free autocrine growth. These results highlight the role of TAF4 as a cofactor in the cellular response to T-RA and identify the genetic programme of a novel cross talk between the T-RA and TGFbeta pathways that leads to deregulated cell growth.
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