Differential interactions of specific nuclear factor I isoforms with the glucocorticoid receptor and STAT5 in the cooperative regulation of WAP gene transcription.
The distal region (-830 to -720 bp) of the rat whey acidic protein (WAP) gene contains a composite response element (CoRE), which has been demonstrated previously to confer mammary gland-specific and hormonally regulated WAP gene expression. Point mutations in the binding sites for specific transcription factors present within this CoRE have demonstrated the importance of both nuclear factor I (NFI) and STAT5 as well as cooperative interactions with the glucocorticoid receptor (GR) in the regulation of WAP gene expression in the mammary gland of transgenic mice. This study reports the characterization of NFI gene expression during mammary gland development and the identification and cloning of specific NFI isoforms (NFI-A4, NFI-B2, and NFI-X1) from the mouse mammary gland during lactation. Some but not all of these NFI isoforms synergistically activate WAP gene transcription in cooperation with GR and STAT5, as determined using transient cotransfection assays in JEG-3 cells. On both the WAP CoRE and the mouse mammary tumor virus long terminal repeat promoter, the NFI-B isoform preferentially activated gene transcription in cooperation with STAT5A and GR. In contrast, the NFI-A isoform suppressed GR and STAT cooperativity at the WAP CoRE. Finally, unlike their interaction with the NFI consensus binding site in the adenovirus promoter, the DNA-binding specificities of the three NFI isoforms to the palindromic NFI site in the WAP CoRE were not identical, which may partially explain the failure of the NFI-A isoform to cooperate with GR and STAT5A.
Mukhopadhyay
S S
SS
Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA.
Wyszomierski
S L
SL
Gronostajski
R M
RM
Rosen
J M
JM
D000256:Adenoviridae / Q000235:genetics; D017398:Alternative Splicing; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D015153:Blotting, Western; D001940:Breast / Q000378:metabolism; D022762:CCAAT-Enhancer-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D002478:Cells, Cultured; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D007774:Lactation; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D008894:Milk Proteins / Q000235:genetics* / Q000378:metabolism*; D008957:Models, Genetic; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D012313:RNA / Q000378:metabolism; D011965:Receptors, Glucocorticoid / Q000235:genetics / Q000378:metabolism*; D020218:Response Elements; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012260:Ribonucleases / Q000378:metabolism; D050799:STAT5 Transcription Factor; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors; D014158:Transcription, Genetic; D014162:Transfection; D051840:Y-Box-Binding Protein 1; D001616:beta-Galactosidase / Q000378:metabolism
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D008894:Milk Proteins; D051839:NFI Transcription Factors; C497646:Nfia protein, mouse; D009687:Nuclear Proteins; D020033:Protein Isoforms; D011965:Receptors, Glucocorticoid; D050799:STAT5 Transcription Factor; C494093:Stat5a protein, mouse; D015534:Trans-Activators; D014157:Transcription Factors; D051840:Y-Box-Binding Protein 1; C070856:YBX1 protein, human; C024471:whey acidic proteins; D012313:RNA; D004247:DNA; D008156:Luciferases; D012260:Ribonucleases; D001616:beta-Galactosidase