Functional antagonism between YY1 and the serum response factor.

Abstract

The rapid, transient induction of the c-fos proto-oncogene by serum growth factors is mediated by the serum response element (SRE). The SRE shares homology with the muscle regulatory element (MRE) of the skeletal ce-actin promoter. It is not known how these elements respond to proliferative and cell-type-specific signals, but the response appears to involve the binding of the serum response factor (SRF) and other proteins. Here, we report that YY1, a multifunctional transcription factor, binds to SRE and MRE sequences in vitro. The methylation interference footprint of YY1 overlaps with that of the SRF, and YY1 competes with the SRF for binding to these DNA elements. Overexpression of YY1 repressed serum-inducible and basal expression from the c-fos promoter and repressed basal expression from the skeletal a-actin promoter. YY1 also repressed expression from the individual SRE and MRE sequences upstream from a TATA element. Unlike that of YY1, SRF overexpression alone did not influence the transcriptional activity of the target sequence, but SRF overexpression could reverse YYl-mediated trans repression. These data suggest that YY1 and the SRF have antagonistic functions in vivo.The CC(AIT)6GG sequence, or CArG motif, is the core of a family of DNA regulatory elements that occur in the promoters and enhancers of genes which are subject to different regulatory controls (12,23). Included in this family of regulatory elements are the c-fos serum response element (SRE), which confers serum-inducible expression, and the skeletal a-actin muscle regulatory element (MRE), which is sufficient for muscle-specific expression when it is placed upstream from a TATA element (22,24). The serum response factor (SRF) binds to the core CArG motif of both elements, while other proteins directly bind to the sequences that flank the CArG motif (9,11,16,22,24,25). In addition, ets-related proteins bind to the c-fos SRE as part of a ternary complex with the SRF (1, 7). Complex protein-nucleic acid interactions presumably allow these elements to respond to diverse intracellular signals, but the functions of the individual factors are generally not known and contradictory findings have been reported (4, 8,10,17,20,26).Here, we report that the transcription factor YY1, also referred to as 6,14,19,21), specifically binds to the c-fos SRE and the skeletal actin MRE in vitro and that the binding of YY1 will inhibit the binding of the SRF transcription factor. YY1 overexpression represses transcription from the c-fos and skeletal actin promoters, and it appears that the repression is mediated, at least in part, by the CArG regulatory elements within these promoters. In contrast to that of YY1, SRF overexpression did not detectably alter expression from these elements; however, SRF overexpression could reverse YY1-mediated trans repression. These data suggest that YY1 and the SRF have antagonistic functions that may result from a competition for binding to DNA. promoter (positions -296 to -323). The MRE sequence is from the chicken skeletal ...

Suppression of c-Fos gene transcription with malignant transformation of human bronchial epithelial cells

“…This could be accounted for by di erences in CREBP phosphorylation or by di erent co-activators/repressors associated with CREBP in these cells. YY1 sites in the c-fos promoter adjacent to SRE and CRE sites have demonstrated positive and negative regulatory e ects through interactions of YY1 with proteins bound to these response elements (Natesan and Gilman, 1993Gilman, ,1995Gualberto et al, 1992). A YY1 site distinct from the ones adjacent to the SRE and CRE was actively bound in tumorigenic 1170I cells, and the role of this YY1 site has not been examined previously.…”

Direct association of YY-1 with c-Myc and the E-box binding protein in regulation of glycophorin gene expression

“…YY-1 binding sites were found in many genes Hariharan et al, 1991;Park and Atchison, 1991;Flanagan et al, 1992) and in most cases, YY-1 exerts its activating or repressing functions through physical and/or functional interaction with other nuclear proteins (Seto et al, , 1993May et al, 1994;Nateson et al, 1993;Lee et al, 1993;Gualberto et al, 1992;Inouye and Seto, 1994;Ushva and Shenk, 1994;Raich et al, 1995). Thus, in the present study, we examined how YY-1 can regulate the LCR-like activity of the mouse glycophorin gene through its interaction with other proteins.…”

“…Within this region there exist 6 di erent nuclear factor binding sites: GATA-1, NF-E2, Spi-1/PU.1, GGTGG , YY-1 and E-box. YY-1, a GLI-Kruppel-related zinc ®nger protein, is a ubiquitously present versatile nuclear transcription factor Hariharan et al, 1991;Park and Atchison, 1991), and regulates expression of many genes by binding to the regulatory elements of these genes (Seto et al, , 1993May et al, 1994;Nateson et al, 1993;Lee et al, 1993;Gualberto et al, 1992;Inouye and Seto, 1994;Ushva and Shenk, 1994;Raich et al, 1995). We examined the functional involvement of YY-1 and the E-box binding protein (EBP) on the LCR-like activity of the mouse glycophorin gene by stably transfecting the mutants in the YY-1 binding site and the neighboring E-box binding site into MEL cells; we demonstrated that YY-1 acts as a regulatory protein in combination with EBP and may regulate LCR-like activity of the mouse glycophorin gene (Nemoto et al, 1996).…”

Activation of the c-fos enhancer by the Erk MAP kinase pathway through two sequence elements: the c-fos AP-1 and p62TCF sites

“…Other factors binding the SRE that have been identi®ed include NFIL6/c/EBPb, YY1, SRE-ZBP and TFII-I-Phox1 (Attar and Gilman, 1992;Grueneberg et al, 1997;Gualberto et al, 1992;Kim et al, 1998;Metz and Zi , 1991). None of these are likely to account for band 3 or the faint band migrating below band 4 in Figure 3a, since they would not be expected to be competed by the FAP1 oligonucleotide which does not span their binding sites (Attar and Gilman, 1992;Grueneberg et al, 1997;Gualberto et al, 1992;Kim et al, 1998;Metz and Zi , 1991).…”

“…None of these are likely to account for band 3 or the faint band migrating below band 4 in Figure 3a, since they would not be expected to be competed by the FAP1 oligonucleotide which does not span their binding sites (Attar and Gilman, 1992;Grueneberg et al, 1997;Gualberto et al, 1992;Kim et al, 1998;Metz and Zi , 1991). E12 was also found to bind the SRE and may bind the FAP1 sequence since it contains its core CANNTG binding site (Metz and Zi , 1991).…”