cDNA cloning and expression of insulinlike growth factor binding protein gene IGFBP-1 in Ctenopharyngodon idellus

Abstract:

In this study, the complete cDNA of a insulinlike growth factor binding gene IGFBP-1 was cloned by rapid amplification of cDNA ends (RACE) in grass carp, Ctenopharyngodon idellus. And mRNA transcripts during embryogenesis and in adult tissues were studied by RT-PCR. The results showed that: (1) The complete cDNA of C.idellus IGFBP-1 is 1 135 bp and its ORF includes 789 bp which coding 262 aminoacid residue. The deduced amino acid analysis showed that the sequence similarities between C.idellus and Cyprinus carpio, Danio rerio, Ictalurus punctatus, Salmo salar, Oncorhynchus mykiss, Seriola quinqueradiata, Mus musculus and Homo sapiens are 94%, 93%, 69%, 60%, 58%, 56%, 40% and 38%, respectively. Its functional Nterminal and Cterminal domains, which are involved in binding with IGF ligand, are very conservative. (2) RT-PCR results demonstrated that IGFBP-1 gene had a low expression in embryos at different stages in C.idellus. Weak mRNA transcripts can be detected after 12 hpf. Tissue distribution results showed that IGFBP-1 mRNA was expressed in liver, kidney, intestines and heart. In terms of its crucial function of IGFBP-1 in IGF signal pathway and as a hypoxiainducible gene, our results provide data for further functional investigations of IGFBP-1 gene in grass carp.