Ig/EBP (C/EBP gamma) is a transdominant negative inhibitor of C/EBP family transcriptional activators.
Analysis of cDNA and genomic clones shows that the murine Ig/EBP (C/EBP gamma) gene encodes a small protein with a predicted molecular weight of 16.4 kDa which contains C/EBP family basic and leucine zipper domains but lacks the transcriptional activation domains present in C/EBP (C/EBP alpha) and NF-IL6 (C/EBP beta). In transfection assays Ig/EBP is neither an activator nor a repressor of transcription; however, Ig/EBP inhibits the transcriptional ability of NF-IL6 (C/EBP beta) and C/EBP (C/EBP alpha), acting as a transdominant negative regulator. Thus Ig/EBP resembles LIP, another negative regulator of the C/EBP family, in both structure and transcriptional activity. Of the three known C/EBP family inhibitors, Ig/EBP, LIP and CHOP-10, only Ig/EBP is ubiquitously expressed. Therefore, Ig/EBP may act as a general buffer for C/EBP activators in many cell types.
Cooper
C
C
Department of Microbiology, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA.
Henderson
A
A
Artandi
S
S
Avitahl
N
N
Calame
K
K
D000818:Animals; D001483:Base Sequence; D022782:CCAAT-Enhancer-Binding Protein-beta; D022762:CCAAT-Enhancer-Binding Proteins; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors*; D005786:Gene Expression Regulation; D015151:Immunoblotting; D016350:Leucine Zippers; D051379:Mice; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors*; D017433:Protein Structure, Secondary; D012097:Repressor Proteins / Q000378:metabolism; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000037:antagonists & inhibitors*; D014158:Transcription, Genetic
D022782:CCAAT-Enhancer-Binding Protein-beta; D022762:CCAAT-Enhancer-Binding Proteins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D016328:NF-kappa B; D009687:Nuclear Proteins; D012097:Repressor Proteins; D014157:Transcription Factors