Cell-specific transcriptional control of the mouse DNA-binding protein mC/EBP.
The mRNA encoding the mouse homolog of C/EBP, a rat DNA-binding protein that participates in activating a number of genes in hepatocytes, is present in liver cells at a far higher concentration than in most other cells, including spleen, kidney, muscle, and the majority of the brain. However, fat cells and intestinal cells contain 25-50% as much mRNA as liver cells. "Run-on" experiments show that the basis for the restricted cellular distribution of the mouse C/EBP mRNA is transcriptional regulation of the gene. We also show that disruption of cell-cell contacts incident to liver cell dispersion results in a prompt and extensive reduction in mouse C/EBP transcription as we had earlier shown to be the case for a group of 10 genes transcribed in a hepatocyte-specific fashion. In contrast, breaking cell contacts and plating the hepatocytes in culture leads to a prolonged increase in transcription of the Jun-B gene that encodes a widely distributed transcription factor. These results illustrate that the regulation of expression of a mammalian regulatory protein with limited tissue distribution is controlled at the level of transcription and depends on cell contacts.
Xanthopoulos
K G
KG
Molecular Cell Biology Laboratory, Rockefeller University, New York, NY 10021.
Mirkovitch
J
J
Decker
T
T
Kuo
C F
CF
Darnell
J E
JE
D000818:Animals; D022762:CCAAT-Enhancer-Binding Proteins; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D005786:Gene Expression Regulation; D005796:Genes; D008099:Liver / Q000378:metabolism; D051379:Mice; D009687:Nuclear Proteins / Q000235:genetics*; D009928:Organ Specificity; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D051381:Rats; D014158:Transcription, Genetic
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D004247:DNA