Studies On Cloning And Expression Analysis Of IGF And IGFBP Genes In Turbot (Scophthalmus Maximus)

As one of the main seawater breedings in the north coastal area of China, turbot(Scophthalmus maximus) has important economic value. This paper mainly study oncultured turbot, from which the relative gene of IGF signal system IGF-2, IGFBP-1,IGFBP-2are studied and taken by the methods of molecular biology in details. Themain results and conclusions are as follows:1. Cloning and expression analysis of Insulin-like growth factorbinding protein-1(IGFBP-1) in turbot (Scophthalmus maximus)In this study, we cloned the full-length cDNA sequences of Insulin-like growthfactor binding protein-1gene from Scophthalmus maximus, the length of the cDNA is1179bp, the coding region from35bp to775bp that encodes a protein of247aminoacids, the amino acid can be divided into three domains, conserved N-terminaldomain and C-terminal domain, the variable central L-domain, the N-domain andC-domain contain18cysteine residues. Tissue expression analysis showed thatigfbp-1mRNA is expressed in liver, spleen, heart, stomach, kidney, intestine, andhighly expressed in liver and spleen.The expression patterns of IGFBP-1gene during embryonic and larvaldevelopmental stages from Scophthalmus maximus were detected by RT-PCR, whichstarted from unfertilized egg, dropped into the lowest in the gastrul stage, grown up inthe following developmental stages and reached the top in the postlarva. The resultshowed that IGFBP-1gene played a important part in early developmental stages ofScophthalmus maximus.2. Cloning and expression analysis of Insulin-like growth factorbinding protein-2(IGFBP-2) in turbot (Scophthalmus maximus) We also cloned the full-length cDNA sequences of Insulin-like growth factorbinding protein-2gene by RACE cDNA amplification, the length of the cDNA is1057bp,the coding region from43bp to852bp that encodes a protein of270amino acids, theamino acid can also be divided into three domains, conserved N-terminal domain andC-terminal domain, the variable central L-domain, the N-domain and C-domaincontain18cysteine residues. Tissue expression analysis showed that igfbp-2mRNA iswidely expressed, and highly expressed in brain, heart, liver, kidney, intestine, andlower in skin, spleen, gill, ovary, and weakly in stomach, and none in the muscle.The expression patterns of IGFBP-2gene during embryonic and larvaldevelopmental stages from Scophthalmus maximus were first detected in the egg ofembryoid stage by RT-PCR, grown up in the following developmental stages, and witha little reduce in the postlarva, but the difference is not significant.3. Cloning of Insulin-like growth factor-2(IGF-2) and expressionanalysis of the Insulin-like growth factor-1,-2(IGF-1,-2) in turbot(Scophthalmus maximus)We cloned the full-length cDNA sequences of Insulin-like growth factor-2(IGF-2)gene with the same method,, the length of the cDNA is880bp, the coding regionfrom166bp to823bp that encodes a protein of219amino acids, the amino acidcontains a signal peptide domain, conserved B,C,A,D and E domain, and with6cysteine residues in B and A domain.Tissue expression analysis showed a widely expression pattern of IGF-1andIGF-2gene, expression can be detected in all tissue besides intestines of IGF-1, andlower in muscle of IGF-2. During embryonic and larval developmental stages, wefound a high level in unfertilized egg and grown higher step by step of IGF-1; also wefound expression in all stages and a high level in gastrul stage, but the difference isnot significant.