Characterization of SAP-1, a protein recruited by serum response factor to the c-fos serum response element.
We used a yeast genetic screen to isolate cDNAs that encode a protein, SRF accessory protein-1 (SAP-1), that is recruited to the c-fos serum response element (SRE) as part of a ternary complex that includes serum response factor (SRF). SAP-1 requires DNA-bound SRF for ternary complex formation and makes extensive DNA contacts to the 5' side of SRF, but does not bind DNA autonomously. Ternary complex formation by SAP-1 requires only the DNA-binding domain of SRF, which can be replaced by that of the related yeast protein MCM1. We isolated cDNAs encoding two forms of SAP-1 protein, SAP-1a and SAP-1b, which differ at their C termini. Both SAP-1 proteins contain three regions of striking homology with the elk-1 protein, including an N-terminal ets domain. Ternary complex formation by SAP-1 requires both the ets domain and a second conserved region 50 amino acids to its C-terminal side. SAP-1 has similar DNA binding properties to the previously characterized HeLa cell protein p62/TCF.
Dalton
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Transcription Laboratory, Imperial Cancer Research Fund, London, England.
Treisman
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R
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D016366:Open Reading Frames; D010957:Plasmids; D011518:Proto-Oncogene Proteins; D015682:Retroviridae Proteins, Oncogenic / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D016415:Sequence Alignment; D026362:Serum Response Factor; D014157:Transcription Factors; D050807:ets-Domain Protein Elk-1; D050808:ets-Domain Protein Elk-4
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D015682:Retroviridae Proteins, Oncogenic; D026362:Serum Response Factor; D014157:Transcription Factors; D050807:ets-Domain Protein Elk-1; D050808:ets-Domain Protein Elk-4