Insulin-like growth factor binding protein 2 is a growth inhibitory protein conserved in zebrafish

• DOI: 10.1073/pnas.96.26.15274
• Publication Date: 2002-07-26T14:35:07Z
• Authors: Cunming Duan; Jun Ding; Qin Li; Wellington Tsai; Kasiani Pozios
• Keywords: 0301 basic medicine; Base Sequence; Sequence Homology, Amino Acid; Molecular Sequence Data; Gene Expression; Sequence Analysis, DNA; Growth Inhibitors; Insulin-Like Growth Factor Binding Protein 2; 03 medical and health sciences; Gene Expression Regulation; Culture Media, Conditioned; Growth Hormone; Animals; Nutritional Physiological Phenomena; Tissue Distribution; Amino Acid Sequence; Insulin-Like Growth Factor I; Conserved Sequence; Zebrafish; Gene Library

Fish serum contains several specific binding proteins for insulin-like growth factors (IGFBPs). The structure and physiological function of these fish IGFBPs are unknown. Here we report the complete primary sequence a zebrafish IGFBP deduced from cDNA clones isolated by library screening rapid amplification ends. full-length 1,757-bp encodes protein 276 aa, which putative 22-residue signal peptide 254-residue mature protein. has predicted molecular size 28,440 Da shows high identity with human IGFBP-2 (52%). identities other <37%. Chinese hamster ovary cells stably transfected secreted 31-kDa protein, bound to IGF-I IGF-II affinity, but did not bind Des(1-3)IGF-I or insulin. Northern blot analyses revealed that transcript is 1.8-kb band expressed in many embryonic adult tissues. In zebrafish, mRNA levels were greatly reduced hormone treatment increased prolonged fasting. When overexpressed added cultured mammalian cells, significantly inhibited IGF-I-stimulated cell proliferation DNA synthesis. These results indicate negative regulator acting downstream hormone-IGF-I axis.