The avian C/EBPgamma gene encodes a highly conserved leucine zipper transcription factor.
The C/EBP family of transcription factors regulates viral and cellular CCAAT/enhancer element-mediated transcription. We report the isolation and characterization of genomic and cDNA clones encoding avian CCAAT/enhancer-binding protein-gamma (C/EBP gamma). A partial cDNA clone for a C/EBP-related gene was previously identified by expression library screening for proteins binding the A1 CCAAT/enhancer motif from the avian leukosis virus long terminal repeat [W. Bowers and A. Ruddell (1992) J. Virol. 66, 6578-6586]. Additional cDNA and genomic clones were generated and sequenced to identify the complete protein coding sequence of this gene. Sequence analysis indicates that this gene encodes the avian homolog of C/EBP gamma. As with the murine C/EBP gamma homolog, the avian C/EBP gamma gene is comprised of two exons, with the open reading frame encoded in exon 2. The 150-aa C/EBP gamma protein is highly conserved, as the avian protein shows more than 80% identity with the murine and human homologs. The sequence of the initiation methionine (-3 caaAUGa +4) from the 150-aa open reading frame has a non-optimal Kozak initiation sequence. In vitro transcription and translation assay of this avian cDNA followed by radioimmunoprecipitation assay using a murine C/EBP gamma antiserum indicates that this non-optimal initiation codon is used to express a 22-kDa DNA-binding protein.
Baglia
L A
LA
Department of Microbiology and Immunology and Cancer Center, University of Rochester, NY 14642, USA.
Bowers
W J
WJ
Ruddell
A
A
D000595:Amino Acid Sequence; D000818:Animals; D022762:CCAAT-Enhancer-Binding Proteins; D002645:Chickens / Q000235:genetics*; D003001:Cloning, Molecular; D017124:Conserved Sequence; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics*; D016366:Open Reading Frames; D016133:Polymerase Chain Reaction / Q000379:methods; D017386:Sequence Homology, Amino Acid
D022762:CCAAT-Enhancer-Binding Proteins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins