CCAAT/enhancer-binding protein-delta (C/EBP-delta) is induced in growth-arrested mouse mammary epithelial cells.
CCAAT/enhancer binding proteins (C/EBPs) are a highly conserved family of DNA-binding proteins that regulate cell growth and differentiation in a highly tissue-specific manner. These experiments investigated the influence of the cell cycle on C/EBP isoform expression in mammary epithelial cells (COMMA D) and fibroblasts (NIH3T3). C/EBP-delta gene expression is induced in COMMA D cells arrested in G0 by serum and growth factor withdrawal or contact inhibition. C/EBP-delta mRNA, nuclear protein content, and DNA binding activity increase during G0 growth arrest and decrease after cell cycle induction in COMMA D cells. Growth arrest is markedly delayed in COMMA D cells expressing a C/EBP-delta antisense construct. C/EBP-beta is induced during G1 of the cell cycle. In contrast to COMMA D cells, C/EBP-beta and C/EBP-delta mRNA levels remain relatively constant in growth-arrested and cell cycle-induced NIH3T3 cells. However, C/EBP homologous protein (CHOP10) mRNA levels markedly increase in growth-arrested NIH3T3 cells. Both COMMA D and NIH3T3 cells express growth arrest-specific (gas1) and JunD during G0. These results demonstrate that COMMA D and NIH3T3 cells achieve a common growth arrest (G0) state by cell-specific strategies that involve the induction of different C/EBP isoforms.
O'Rourke
J
J
Ohio State University Biochemistry Program, Ohio State University, Columbus, Ohio 43210, USA.
Yuan
R
R
DeWille
J
J
D016475:3T3 Cells; D000818:Animals; D051743:CCAAT-Enhancer-Binding Protein-delta; D022762:CCAAT-Enhancer-Binding Proteins; D002451:Cell Compartmentation; D018797:Cell Cycle Proteins; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005260:Female; D058851:GPI-Linked Proteins; D018507:Gene Expression Regulation, Developmental; D006657:Histones / Q000378:metabolism; D008321:Mammary Glands, Animal / Q000166:cytology*; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D009687:Nuclear Proteins / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry / Q000276:immunology; D012333:RNA, Messenger / Q000235:genetics; D014157:Transcription Factors / Q000378:metabolism*
D022762:CCAAT-Enhancer-Binding Proteins; C497253:Cebpd protein, mouse; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C096192:GAS1 protein, human; D058851:GPI-Linked Proteins; C501180:Gas1 protein, mouse; D006657:Histones; D008565:Membrane Proteins; D009687:Nuclear Proteins; D010455:Peptides; D012333:RNA, Messenger; D014157:Transcription Factors; D051743:CCAAT-Enhancer-Binding Protein-delta