Cloning Of Growth Hormone Releasing Hormone Mature Peptide Gene From Guangxi Bama Mini-Pig And The Effect Of GHRH Gene Expression Plasmid On Growth Performance Of Mouse

Growth hormone releasing hormone(GHRH) is secreted and synthesized by thehypothalamus in animals which regulates pituitary GH synthesis and secretion. GHRHplays an important role in animal growth, development and metabolism.In this study, the GHRH exon3 was amplified by a specific pair of primers usingGuangxi BaMa mini-pig genome as template,after which the mature peptide sequencewas cloned by over-bang extension PCR protocol and then ligated into sub-clone vectorfor sequencing and restriction analysis. The result showed that the cloned GHRH exon3and mature peptide gene from Guangxi BaMa mini-pig contained 105 and 132bp,respectively. The homologous analysis indicated that the homologous rate was 97.14%compared with the porcine GHRH exon3 reported in GenBank. Three nonsencemutations were detected in GHRH exon3 sequence of BaMa Mini-pig.To study the effect of pig's GHRH expression plasmid on animal growth performance,the PEGFP-GHRH plasmid was constructed.Forty-two mouse with similar body weight(14.05±5.48)g were selected and assigned randonly to two group of 21 mouse each andsubjected to two treatment as followed:1) control group- muscular injection with 0.5μg PEGFP-N1 plamid/g body weight.2) treated group- muscular injection with 0.5μgPEGFP-GHRH plamid/g body weight. The results indicated that the extra-GHRH can beexpressed in the muscles continuously until 15d after injection.The muscular injection ofPEGFP-GHRH plasmid increased the body weight significantly (P＜0.05) duing 10 to 25dafter injection. The injection of PEGFP-GHRH plasmid significantly increased the averagedaily gain by 12.3 % (P＜0.05) during 0 to 25d after treatment.