Molecular cloning and sequence analysis of the cDNA for the putative β subunit of the type-II gonadotrophin from the European eel

• Published in: Journal of Molecular Endocrinology
• Main Authors: Quérat, B., Moumni, M., Jutisz, M., Fontaine, Y.A., Counis, R.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Bioscientifica 1990
• Subjects: Endocrinology; Molecular Biology; Anguilla anguilla
• Online Access: http://dx.doi.org/10.1677/jme.0.0040257; https://jme.bioscientifica.com/view/journals/jme/4/3/jme_4_3_008.xml; https://jme.bioscientifica.com/downloadpdf/journals/jme/4/3/jme_4_3_008.xml

ABSTRACT 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 β subunit of eel GTH-II. A cDNA library was constituted in λgt10 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 β 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 β-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.