Molecular cloning and expression analysis of rainbow trout (Oncorhynchus mykiss) CCAAT/enhancer binding protein genes and their responses to induction by GH in vitro and in vivo.
CCAAT/enhancer-binding proteins (C/EBPs) are transcription factors consisting of six isoforms and play diverse physiological roles in vertebrates. In rainbow trout (Oncorhynchus mykiss), in addition to the reported C/EBPbeta1, we have isolated cDNA of four other isoforms, C/EBPalpha, C/EBPbeta2, C/EBPdelta1, C/EBPdelta2, from the liver. Comparison of the deduced amino acid sequence of rainbow trout C/EBPs with those of other vertebrates revealed that C/EBP isoforms are highly conserved. The profiles of tissue-specific expression of individual C/EBP isoform mRNA, determined by quantitative real-time (RT)-PCR showed distinct patterns. Furthermore, injection of bovine GH into yearling rainbow trout resulted in a significant increase of mRNA levels of C/EBPbeta1, C/EBPbeta2, and C/EBPdelta2 but not C/EBPalpha and C/EBPdelta1 in the liver. GH-dependent increase of mRNA levels of C/EBPbeta1, C/EBPbeta2, C/EBPdelta2, and IGF-II were also confirmed by treating rainbow trout hepatoma cells expressing a goldfish GH receptor with bGH. Together with our previous findings, the results presented in this paper strengthen our previous hypothesis that GH may regulate the expression of the IGF-II gene via mediating the expression of C/EBPbeta1, C/EBPbeta2, and C/EBPdelta2 mRNA.
Lo
Jay H
JH
Department of Molecular and Cell Biology, University of Connecticut, 91 N. Eagleville Road, U-3125, Storrs, CT 06269, USA.
Chiou
Pinwen Peter
PP
Lin
C M
CM
Chen
Thomas T
TT
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics*; D002417:Cattle; D002460:Cell Line; D003001:Cloning, Molecular; D015870:Gene Expression / Q000187:drug effects; D013006:Growth Hormone / Q000494:pharmacology*; D008099:Liver / Q000378:metabolism*; D008969:Molecular Sequence Data; D017686:Oncorhynchus mykiss / Q000235:genetics*; D020033:Protein Isoforms / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D022762:CCAAT-Enhancer-Binding Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D013006:Growth Hormone