Isolation and characterization of the goldfish thyrotropin beta subunit gene including the 5'-flanking region.
The complete gene encoding the beta subunit of thyrotropin (thyroid-stimulating hormone, TSH) was isolated from a goldfish genomic library. The goldfish TSHbeta subunit gene, which is approximately 2.0 kilobase pairs (kb) in length, consisted of three exons and two introns. The first intron was much longer (0.89 kb) than the second intron (0.3 kb) as are TSHbeta genes in mammalian species. On the basis of the location of the first intron, the goldfish TSHbeta gene belongs to the mammalian TSHbeta/FSHbeta gene group, which is distinct from the LHbeta group. Inspection of the 5'-flanking and exon 1 regions of the goldfish TSHbeta gene (1.2 kb) revealed the presence of several putative cis-acting elements, including the negative triiodothyronine (T(3))-responsive element (nTRE), Pit-1 element, and GATA-2 element. Comparison of the goldfish sequence with mammalian TSHbeta promoter sequences showed an identical region, nTRE, in the first exon-intron junction region. An in vitro study using dispersed goldfish pituitary cells showed that T(3) treatment (20 ng/ml) suppressed the TSHbeta mRNA level in the cells. These data indicate that (1) the basic structure of TSHbeta genes is highly conserved in vertebrates and that (2) T(3) acts directly on the pituitary and inhibits TSHbeta gene expression in goldfish, probably via the nTRE in the TSHbeta gene.
Sohn
Y C
YC
Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan.
Yoshiura
Y
Y
Suetake
H
H
Kobayashi
M
M
Aida
K
K
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000494:pharmacology; D005091:Exons; D050989:GATA2 Transcription Factor; D015870:Gene Expression / Q000187:drug effects; D015723:Gene Library; D006054:Goldfish / Q000235:genetics*; D007438:Introns; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D020218:Response Elements; D016415:Sequence Alignment; D017421:Sequence Analysis; D013972:Thyrotropin / Q000737:chemistry / Q000235:genetics*; D050817:Transcription Factor Pit-1; D014157:Transcription Factors / Q000494:pharmacology; D014284:Triiodothyronine / Q000494:pharmacology
D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D050989:GATA2 Transcription Factor; D050817:Transcription Factor Pit-1; D014157:Transcription Factors; D014284:Triiodothyronine; D013972:Thyrotropin