The TATA binding protein associated factor 4b (TAF4b) mediates FSH stimulation of the IGFBP-3 promoter in cultured porcine ovarian granulosa cells.
We have established the gene for IGF binding protein-3 (IGFBP-3) as a target for FSH action. FSH effects on this gene require the PKA pathway as well as the PI-3 kinase and MAPK pathways. At the IGFBP-3 promoter, FSH effects depend on a site for TATA box binding protein (TBP) and formation of a high molecular weight transcription complex. To further elucidate FSH effects on the downstream events involving the TBP site, we cloned a pig TAF4b cDNA into a P-Flag expression vector. By co-transfecting granulosa cells with the IGFBP-3 promoter, we found that TAF4b mimics and enhances FSH induction of IGFBP-3 reporter activity. Using RT-PCR we showed that FSH stimulates expression of TAF4b. This would suggest that the role of TAF4b in follicular development is regulated by FSH. TAF4b may thus be the TFIID component that binds to the TBP site on the IGFBP-3 promoter and is essential for FSH induction of IGFBP-3.
Ongeri
Elimelda Moige
EM
Pennsylvania State University, College of Medicine, Hershey Medical Center, Hershey, PA 17033, United States. emo11@psu.edu
Verderame
Michael F
MF
Hammond
James M
JM
D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D003001:Cloning, Molecular; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism* / Q000494:pharmacology; D005786:Gene Expression Regulation; D017930:Genes, Reporter / Q000187:drug effects; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism*; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000235:genetics*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D010053:Ovary / Q000187:drug effects / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000187:drug effects; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D034421:Sus scrofa / Q000235:genetics / Q000378:metabolism*; D035362:Transcription Factor TFIID / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic / Q000187:drug effects
D018972:Insulin-Like Growth Factor Binding Protein 3; D012333:RNA, Messenger; D035362:Transcription Factor TFIID; D005640:Follicle Stimulating Hormone; D019869:Phosphatidylinositol 3-Kinases; D019908:Proto-Oncogene Proteins c-raf; D017868:Cyclic AMP-Dependent Protein Kinases; D020929:Mitogen-Activated Protein Kinase Kinases