Analysis of the structure and expression of the chicken gene encoding a homolog of the human RREB-1 transcription factor.
Ras proteins are involved in a number of signal transduction pathways including the mitogen-activated kinase cascade. Activated MAPKs translocate to the nucleus and phosphorylate transcription factors such as c-myc, TCF and AP-1. Recently, a Ras-responsive element binding transcription factor, RREB-1, was cloned from a human medullary thyroid carcinoma cell line. RREB-1 is a zinc finger protein that binds to a Ras-responsive element in the promoter of the human calcitonin gene. We report the cloning of the chicken homologue to human RREB-1. Amino-acid alignment demonstrates that chicken and human RREB-1 are 53% identical and 69% similar. Genomic southern analysis indicates that chicken rreb-1 is a single-copy gene in the chicken genome. We demonstrate that chicken and human rreb-1 display the same tissue distribution, being expressed in all tissues examined except the brain. Interestingly, chicken RREB-1 has an extended N-terminus and contains 16 zinc fingers of the TFIIIA subclass, in comparison to human RREB-1 which was reported to contain only four zinc fingers. The size discrepancy between the two predicted gene products is further discussed. An unusual structural feature of RREB-1 is the widely spaced arrangement of the zinc fingers.
Miyake
J H
JH
Department of Chemistry and Molecular Biology Institute, San Diego State University, CA 92182, USA.
Szeto
D P
DP
Stumph
W E
WE
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D002645:Chickens; D018076:DNA, Complementary / Q000737:chemistry / Q000302:isolation & purification; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D009928:Organ Specificity / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics*; D016335:Zinc Fingers / Q000235:genetics*; D018631:ras Proteins / Q000235:genetics*
D018076:DNA, Complementary; D004268:DNA-Binding Proteins; C101743:RREB1 protein, human; D014157:Transcription Factors; D018631:ras Proteins