Organization and Nucleotide Sequence of the Mouse α-Subunit Gene of the Pituitary Glycoprotein Hormones

Abstract

We have isolated and determined the nucleotide sequence of the mouse alpha-subunit gene of the pituitary glycoprotein hormones. No detectable rearrangements were observed from the cloned gene when compared with total genomic DNA. The gene is approximately 13.5 kb in size and consists of 4 exons and 3 introns. The 5' untranslated region is encoded by exon 1 and 14 bp of exon 2. A large first intron of about 10 kb interrupts the 5' untranslated region. The coding region is present in exons 2, 3, and 4, while the 3' untranslated region is contained entirely within exon 4. A number of mouse B1 and B2 repeats are present in the 5'-flanking region, the first and third introns, as well as in the 3'-flanking region. In contrast to the mouse beta-subunit gene of thyrotropin, primer extension analysis revealed that the alpha-subunit gene has a single transcriptional start site and that the primary transcript does not exhibit alternative exon splicing. The transcriptional start site is identical in both mouse pituitaries and in TtT97 thyrotropic tumors and is responsive to thyroidal status. The 5'-flanking region contains a sequence that is homologous to a single copy of the duplicated 18-bp cyclic AMP-responsive element of the human alpha-subunit gene. Sequences homologous to putative thyroid-responsive and estrogen responsive elements are present in the 5'-flanking region and may be important in the multihormonal regulation of the alpha-subunit gene in throtrophs and gonadotrophs, respectively.

Targeted disruption of the pituitary glycoprotein hormone alpha-subunit produces hypogonadal and hypothyroid mice.

“…The coding region of the 96-amino-acid protein is contained within exons 2, 3, and 4 (Gordon et al 1988). A targeting vector was constructed containing the neomycin resistance gene (neo)inserted within the third exon and the herpes simplex virus (HSV) thymidine kinase gene at the 3' end (Fig.…”

“…A 4-kb HindIII fragment of the mouse glycoprotein hormone c,-subunit gene subcloned in pGEM7Zf + served as a backbone for constructing the targeting vector (Gordon et al 1988). A 1.7-kb NotI-BamHI PGKneo fragment from the pPNT plasmid (Tybulewicz et al 1991} was incubated with T4 polymerase to create blunt ends and ligated into a unique Bali site in exon 3 of the mouse ~-subunit gene.…”

Expression of the glycoprotein hormone alpha-subunit gene in the placenta requires a functional cyclic AMP response element, whereas a different cis-acting element mediates pituitary-specific expression.

“…*, The only nucleotide in the CRE region that is different between the human and bovine genes. (B) Sequence of the human a-subunit CRE and sequences from homologous regions in the bovine, murine (13), and rat (4) genes. Lowercase letters and the dash represent differences and a deletion, respectively, relative to the human sequence.…”

Cloning of the Genes for the Pituitary Glycoprotein Hormone α and Follicle-Stimulating Hormone β Subunits in the Japanese Crested Ibis, Nipponia nippon

“…All the PGH α genes previously reported in mammals and teleosts consist of four exons and three introns (Fiddes and Goodman, 1981;Goodwin et al ., 1983;Burnside et al ., 1988;Gordon et al ., 1988;Kato et al ., 1990;Golos et al ., 1991;Huang et al ., 1992;Suzuki et al ., 1995). The exonintron structure in the ibis PGH α gene was compared with that of carp (Huang et al, 1992), mouse , bovine (Goodwin et al, 1983) and human (Fiddes and Goodman, 1981) (Fig.…”