Molecular cloning and sequence analysis of the cDNA for the putative beta subunit of the type-II gonadotrophin from the European eel.
Oestradiol treatment enhances type-II gonadotrophin (GTH-II) synthesis in the European eel (Anguilla anguilla) at the silver stage. As a first step in studying the molecular mechanisms involved in this stimulation, we cloned and characterized the cDNA encoding the beta subunit of eel GTH-II. A cDNA library was constituted in lambda gt10 from oestradiol-treated eels. It was screened using an oligodeoxyribonucleotide mixed probe designed to be complementary to a highly conserved region of cDNAs from several LH-related beta subunits. Several clones were obtained and four were subcloned in pUC13 and sequenced. The longest clones comprised a 420 bp coding sequence, plus 5' and 3' untranslated regions of 36 and 172 bp respectively. Comparison with GTH-II from other teleost fish permitted the localization of the putative cleavage site of a 24 amino acid signal peptide. The resulting 116 amino acid apopeptide had well-conserved cysteine positions and a putative N-linked glycosylation site; homology was 70-80% with GTH-II from other fish, 45% with LH from mammals and birds, 38% with mammalian FSH and only 35% with fish GTH-I. Preliminary results indicated a strong positive effect of oestradiol treatment on the level of the putative GTH-II beta-subunit mRNA. This supports our proposal that the European eel provides a suitable model for studying the positive regulation of gonadotrophin synthesis by gonadal steroids.
Quérat
B
B
Laboratoire des Hormones Polypeptidiques, CNRS, Gif sur Yvette, France.
Moumni
M
M
Jutisz
M
M
Fontaine
Y A
YA
Counis
R
R
D000595:Amino Acid Sequence; D000811:Anguilla / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D015342:DNA Probes; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D005399:Fishes / Q000235:genetics; D005640:Follicle Stimulating Hormone / Q000235:genetics; D006065:Gonadotropins, Pituitary / Q000235:genetics*; D007986:Luteinizing Hormone / Q000235:genetics; D008969:Molecular Sequence Data; D012689:Sequence Homology, Nucleic Acid
D015342:DNA Probes; D006065:Gonadotropins, Pituitary; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D004247:DNA