Yoshiura Y, Kobayashi M, Kato Y, Aida K
Department of Aquatic Bioscience, University of Tokyo, Japan.
Gen Comp Endocrinol. 1997 Mar;105(3):379-89. doi: 10.1006/gcen.1996.6839.
Two types of cDNAs (GTH-I beta and -II beta) that encode the beta subunit of goldfish gonadotropin were cloned from a goldfish pituitary cDNA library. The nucleotide sequence of GTH-I beta cDNA was 616 bp long, encoding 130 amino acids, and that of GTH-II beta was 552 bp long, encoding 140 amino acids. These two types of goldfish GTH beta subunits showed an identity of 52% in the nucleotide sequence and 38% in the amino acid sequence. When compared to mammalian GTH beta subunits, goldfish GTH-I beta showed higher homology to FSH-beta s than LH-beta s, and goldfish-II beta to LH-beta s. Genomic Southern blot analysis revealed that cyprinid species harbored genes which were homologous to goldfish GTH-I beta and -II beta, demonstrating the duality of GTH in cyprinid fish as has been shown in other teleost fish. Northern blot analysis of GTH-I beta and -II beta mRNAs in goldfish at differing stages of ovarian maturity (immature, maturing, mature, and regressed) showed that both GTH-I beta and -II beta mRNA levels increased with the progression of maturity and declined in regressed stage. These results suggested that gonadal development in the goldfish was regulated by the two GTHs.
从金鱼脑垂体cDNA文库中克隆出两种编码金鱼促性腺激素β亚基的cDNA（GTH - Iβ和 - IIβ）。GTH - Iβ cDNA的核苷酸序列长616 bp，编码130个氨基酸；GTH - IIβ cDNA的核苷酸序列长552 bp，编码140个氨基酸。这两种金鱼GTHβ亚基在核苷酸序列上的同一性为52%，在氨基酸序列上的同一性为38%。与哺乳动物GTHβ亚基相比，金鱼GTH - Iβ与FSH - β的同源性高于与LH - β的同源性，金鱼GTH - IIβ与LH - β的同源性更高。基因组Southern印迹分析显示，鲤科鱼类含有与金鱼GTH - Iβ和 - IIβ同源的基因，这表明鲤科鱼类中的促性腺激素具有二元性，正如在其他硬骨鱼类中所显示的那样。对处于不同卵巢成熟阶段（未成熟、成熟中、成熟和退化）的金鱼进行GTH - Iβ和 - IIβ mRNA的Northern印迹分析表明，随着成熟进程，GTH - Iβ和 - IIβ mRNA水平均升高，而在退化阶段下降。这些结果表明，金鱼的性腺发育受这两种促性腺激素调节。
