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Isoform-specific regulation of the CCAAT/enhancer-binding protein family of transcription factors by 3',5'-cyclic adenosine monophosphate in Sertoli cells.
Grønning, L M; Dahle, M K; Taskén, K A; Enerbäck, S; Hedin, L; Taskén, K; Knutsen, H K.
Affiliation
  • Grønning LM; Institute of Medical Biochemistry, University of Oslo, Norway. l.m.gronning@basalmed.uio.no
Endocrinology ; 140(2): 835-43, 1999 Feb.
Article in En | MEDLINE | ID: mdl-9927313
The C/EBP (CCAAT/enhancer-binding protein) family of transcription factors is important for differentiation, lipid biosynthesis, and metabolism. Here, we demonstrate for the first time the presence of C/EBP alpha, beta, delta, and zeta messenger RNA (mRNA) and protein in Sertoli cell primary cultures. Treatment with FSH or 8-CPTcAMP strongly induced C/EBP beta mRNA above basal levels with rapid and transient kinetics in Sertoli cell primary cultures as well as in whole testes from hypophysectomized rats. Whereas C/EBP beta mRNA was induced approximately 50-fold, C/EBP delta mRNA was induced 5- to 8-fold by cAMP in Sertoli cells. Messenger RNA for C/EBP beta and delta were induced by inhibition of protein synthesis with cycloheximide and cycloheximide acted synergistically with cAMP. Immunoblots with C/EBP antibodies demonstrated a strong induction of C/EBP beta, delta, and zeta by cAMP. Electrophoretic mobility shift analysis of nuclear proteins from cAMP-treated Sertoli cells using a C/EBP consensus oligonucleotide and antibodies revealed specific binding of C/EBP/DNA complexes, the majority of which were supershifted by C/EBP beta antibody. Transfections of Sertoli cells with a C/EBP reporter construct showed approximately 3-fold induction of reporter gene activity by cAMP. In contrast, the reporter gene vector with a mutated form of the C/EBP binding site, was almost unresponsive to cAMP in transfections of Sertoli cells. Furthermore, C/EBP beta expression increased the activities of two promoters known to be cAMP-responsive in Sertoli cells. Thus, the early induction of C/EBP isoforms by cAMP may play a role in FSH-dependent regulation of late response genes in Sertoli cells.
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Collection: 01-internacional Database: MEDLINE Main subject: Sertoli Cells / Transcription Factors / Receptors, Invertebrate Peptide / Cyclic AMP Limits: Animals Language: En Journal: Endocrinology Year: 1999 Document type: Article Affiliation country: Norway Country of publication: United States
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Collection: 01-internacional Database: MEDLINE Main subject: Sertoli Cells / Transcription Factors / Receptors, Invertebrate Peptide / Cyclic AMP Limits: Animals Language: En Journal: Endocrinology Year: 1999 Document type: Article Affiliation country: Norway Country of publication: United States