The Australian brushtail possum (Trichosurus vulpecula) gonadotrophin alpha-subunit: analysis of cDNA sequence and pattern of expression.
A cDNA sequence from the gonadotrophin alpha-subunit mRNA of Australian brushtail possum (Trichosurus vulpecula) has been determined and analysed. Comparison with seven eutherian mammalian gonadotrophin alpha-subunit gene sequences revealed an average of 82.6% homology between the coding region nucleotide sequences and 88.8% identity between the predicted amino acid sequences. The predicted possum gonadotrophin alpha-subunit protein has ten evolutionarily conserved cysteine residues, two potential N-linked glycosylation sites and a putative enzyme recognition sequence which it has been suggested is required for sulphation of carbohydrate moieties. Comparison of the possum gonadotrophin alpha-subunit 3' untranslated region (UTR) sequence with the 3' UTRs of eutherian alpha-subunit transcripts revealed sequence homology. In particular, an 18 nucleotide imperfect palindromic sequence present in the possum 3' UTR, with the potential to form a hairpin loop, was found to be evolutionarily conserved and present in five out of seven eutherian alpha-subunit 3' UTR sequences. In situ hybridization localized the transcripts to a sub-population of anterior pituitary cells presumed to be gonadotrophs and thyrotrophs. In summary, these results indicate considerable conservation of the structure and function of the gonadotrophin alpha-subunit protein since the divergence of the marsupial and eutherian mammalian lineages.
Fidler
A E
AE
AgResearch Wallaceville, Upper Hutt, New Zealand.
Lawrence
S B
SB
Vanmontfort
D M
DM
Tisdall
D J
DJ
McNatty
K P
KP
D000595:Amino Acid Sequence; D000818:Animals; D001315:Australia; D001483:Base Sequence; D002417:Cattle; D017931:DNA Primers; D018076:DNA, Complementary; D005786:Gene Expression Regulation; D015292:Glycoprotein Hormones, alpha Subunit / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D006736:Horses; D006801:Humans; D008322:Mammals / Q000235:genetics*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009893:Opossums / Q000235:genetics*; D010902:Pituitary Gland / Q000166:cytology / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D012756:Sheep; D013552:Swine
D017931:DNA Primers; D018076:DNA, Complementary; D015292:Glycoprotein Hormones, alpha Subunit; D012333:RNA, Messenger