The Cloning And Sequence Analysis Of The Full CDNA Of Reindeer Ghrelin

Braingut peptide is the polypeptide that is distributed in central nervous system and gastrointestinal tract; it has important regulatory effect to gastrointestinal tract function. 1999, Ghrelin is a new braingut peptide which is discovered by Kojima et al in Janpan. Ghrelin is the only nature ligand of GHSR which is found in vivo so far. Ghrelin is widely distributed in animals, it has many biologic activities such as stimulating the adenohypophysis releasing growth hormone, stimulating appetite, and accommodating energy metabolism, etc. Furthermore, ghrelin is correlated with many diseases in clinic application. Therefore, ghrelin has many effects to clinical diseases.In this study, total RNA was extracted from the abomasum epithelial tissue of a reindeer and the middle sequence of cDNA encoding reindeer ghrelin was amplified by the reverse transcription-PCR (RT-PCR ). Then, the full-length cDNA of reindeer ghrelin was amplified successfully using RACE (Rapid Amplification of cDNA Ends). The full-length cDNA of 604 bp contains a ORF of 402bp, a 5′untranslated region (5′UTR) of 57 bp, a start codon TGA, a 3′UTR of 128bp and ploy(A)14. The ORF encodes a preproghrelin of 64 amino acid residues, which includes a signal peptide of 41 amino acid residues in N-terminal, a mutured peptide of 27 amino acid residues, C-terminal of 6 amino acid residues. The sequences of matured peptide at 1, 4, 5, 6, 7 sit are highly conserved. The C-terminal peptide P-R (proline and arginine) of matured peptide is the recognition site. Compared with the preproghrelin of other species, the sequences of signal peptide in preproghrelin was the longest one, the reasons need tobe study further.