Testis-specific and developmentally induced expression of a ghrelin gene-derived transcript that encodes a novel polypeptide in the mouse.
Ghrelin is a novel growth hormone-releasing peptide isolated from rat stomach. In the present study, we report expression of a ghrelin gene-derived transcript (GGDT) in the mouse testis. Analysis of GGDT cDNA revealed that the 68 bp sequence at the 5'-end was unique and the remaining 252 bp sequence was identical with the sequence encoded by exons 4 and 5 of mouse ghrelin gene. The 5'-unique sequence encoded 12 amino acid residues being in-frame with the C-terminal 42 amino acid sequence of mouse ghrelin. The 54-amino-acid polypeptide encoded by GGDT contained no apparent signal peptide sequence but possessed a nuclear localization signal-like sequence. Ghrelin mRNA was extensively expressed in the stomach, while GGDT was expressed only in the testis. The 5'-unique sequence of GGDT was identified between exons 3 and 4 of the ghrelin gene, indicating that GGDT was generated by alternative usage of the 68 bp exon as the testis-specific first exon. The GGDT expression in the testis was initiated and increased after 2 weeks of postnatal period. These results indicate that the expression of GGDT is regulated in testis-specific and developmental stage-specific manners.
Tanaka
M
M
Department of Biochemistry, Faculty of medicine, Mie University, Tsu, Mie, Japan. mi-tana@doc.medic.mie-u.ac.jp
Hayashida
Y
Y
Nakao
N
N
Nakai
N
N
Nakashima
K
K
D000367:Age Factors; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005091:Exons; D005753:Gastric Mucosa / Q000378:metabolism; D054439:Ghrelin; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D036361:Peptide Hormones; D010455:Peptides / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D013737:Testis / Q000254:growth & development / Q000378:metabolism*
D054439:Ghrelin; D036361:Peptide Hormones; D010455:Peptides; D012333:RNA, Messenger