Transcriptional Regulation of the Cytosolic Chaperonin θ Subunit Gene, Cctq, by Ets Domain Transcription Factors Elk-1, Sap-1a, and Net in the Absence of Serum Response Factor

• Published in: The Journal of biological chemistry 2003-08, Vol.278 (33), p.30642-30651
• Main Authors: Yamazaki, Yuji, Kubota, Hiroshi, Nozaki, Masami, Nagata, Kazuhiro
• Format: Article
• Language: English
• Subjects: Animals; Base Sequence; Binding Sites; Chaperonin Containing TCP-1; Chaperonins - chemistry; Chaperonins - genetics; Cytosol - physiology; DNA-Binding Proteins - metabolism; Enzyme Inhibitors - pharmacology; ets-Domain Protein Elk-1; ets-Domain Protein Elk-4; Flavonoids - pharmacology; Genes, Reporter; Genetic Complementation Test; Glycoproteins - metabolism; HeLa Cells; Humans; In Vitro Techniques; MAP Kinase Signaling System - drug effects; MAP Kinase Signaling System - physiology; Mice; Molecular Sequence Data; Protein Structure, Tertiary; Proto-Oncogene Proteins - metabolism; ras Proteins - metabolism; Saposins; Serum Response Factor - pharmacology; Sphingolipid Activator Proteins; Transcription Factors; Transcription, Genetic - physiology; Up-Regulation - genetics
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M212242200

The chaperonin-containing t-complex polypeptide 1 (CCT) is a molecular chaperone that facilitates protein folding in eukaryotic cytosol, and the expression of CCT is highly dependent on cell growth. We show here that transcription of the gene encoding the θ subunit of mouse CCT, Cctq, is regulated by the ternary complex factors (TCFs), Elk-1, Sap-1a, and Net (Sap-2). Reporter gene assay using HeLa cells indicated that the Cctq gene promoter contains a cis-acting element of the CCGGAAGT sequence (CQE1) at –36 bp. The major CQE1-binding proteins in HeLa cell nuclear extract was recognized by anti-Elk-1 or anti-Sap-1a antibodies in electrophoretic mobility shift assay, and recombinant Elk-1, Sap-1a, or Net specifically recognized CQE1. The CQE1-dependent transcriptional activity in HeLa cells was virtually abolished by overexpression of the DNA binding domains of TCFs. Overexpression of full-length TCFs with Ras indicated that exogenous TCFs can regulate the CQE1-dependent transcription in a Ras-dependent manner. PD98059, an inhibitor of MAPK, significantly repressed the CQE1-dependent transcription. However, no serum response factor was detected by electrophoretic mobility shift assay using the CQE1 element. These results indicate that transcription of the Cctq gene is regulated by TCFs under the control of the Ras/MAPK pathway, probably independently of serum response factor.