Gene structure and functional characterization of growth hormone in dogfish, Squalus acanthias.
Dogfish (Squalus acanthias) growth hormone (GH) was identified by cDNA cloning and protein purification from the pituitary gland. Dogfish GH cDNA encoded a prehormone of 210 amino acids (aa). Sequence analysis of purified GH revealed that the prehormone is composed of a signal peptide of 27 aa and a mature protein of 183 aa. Dogfish GH showed 94% sequence identity with blue shark GH, and also showed 37-66%, 26%, and 48-67% sequence identity with GH from osteichtyes, an agnathan, and tetrapods. The site of production was identified through immunocytochemistry to be cells of the proximal pars distalis of the pituitary gland. Dogfish GH stimulates both insulin-like growth factor-I and II mRNA levels in dogfish liver in vitro. The dogfish GH gene consisted of five exons and four introns, the same as in lamprey, teleosts such as cypriniforms and siluriforms, and tetrapods. The 5'-flanking region within 1082 bp of the transcription start site contained consensus sequences for the TATA box, Pit-1/GHF-1, CRE, TRE, and ERE. These results show that the endocrine mechanism for growth stimulation by the GH-IGF axis was established at an early stage of vertebrate evolution, and that the 5-exon-type gene organization might reflect the structure of the ancestral gene for the GH gene family.
Moriyama
Shunsuke
S
School of Fisheries Sciences, Kitasato University, Sanriku, Iwate, Japan. morisuke@kitasato-u.ac.jp
Oda
Mayumi
M
Yamazaki
Tomohide
T
Yamaguchi
Kiyoko
K
Amiya
Noriko
N
Takahashi
Akiyoshi
A
Amano
Masafumi
M
Goto
Tomoaki
T
Nozaki
Masumi
M
Meguro
Hiroshi
H
Kawauchi
Hiroshi
H
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D016000:Cluster Analysis; D017931:DNA Primers / Q000235:genetics; D040461:Gene Components / Q000235:genetics*; D013006:Growth Hormone / Q000235:genetics*; D007150:Immunohistochemistry; D008099:Liver / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D010902:Pituitary Gland / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D048251:Squalus acanthias / Q000235:genetics*
D017931:DNA Primers; D013006:Growth Hormone