Gonadotropin alpha-subunit glycoprotein from channel catfish (Ictalurus punctatus) and its expression during hormone-induced ovulation.
Gonadotropin alpha-subunit glycoprotein from channel catfish (Ictalurus punctatus) and its expression during hormone-induced ovulation.
复制标题
斑点叉尾鮰 (Ictalurus punctatus) 的促性腺激素 α 亚基糖蛋白及其在激素诱导排卵期间的表达。
DOI：
--
复制
发表时间：
1997
期刊：
影响因子：
--
通讯作者：
R. Dunham
中科院分区：
文献类型：
--
作者：
Z. Liu;P. Li;B. Argue;R. Dunham
采用聚合酶链式反应（PCR）技术，从垂体RNA质粒文库中克隆了通道鲶鱼促性腺激素(GTH) α亚基糖蛋白的互补DNA （cDNA）。通过两个PCR反应完成cDNA的完整克隆：一个是用上游义引物加上位于质粒载体中cDNA poly(A)序列下游的通用测序引物，扩增cDNA的下游部分；另一种是下游反义引物加上位于质粒载体中cDNA义链最5'端上游的反测序引物，用于扩增cDNA的上游部分。两个扩增片段重叠约70 bp。核苷酸序列分析表明，鲶鱼GTH α -亚基长度为658 bp，编码116个氨基酸，包含42 bp的5‘非翻译区（NTR）和265 bp的3’ NTR。推导出的鲶鱼GTH α亚基氨基酸序列与其他克隆硬骨鱼GTH α亚基氨基酸序列高度保守。GTH α亚基在产卵季雌性诱导排卵前就已高表达。鲤鱼垂体提取物（一种产卵诱导试剂）仅诱导高1.4倍的GTH α亚基RNA表达，但包括非常快速的卵子成熟和排卵。这一出乎意料的结果表明，GTH α亚基可能不是排卵和产卵的限制因素，这可能受激素诱导排卵过程中GTH α亚基与特定β亚基的比例偶联变化的调节。
Complementary DNA (cDNA) encoding the channel catfish (Ictalurus punctatus) gonadotropin (GTH) alpha-subunit glycoprotein was cloned by polymerase chain reaction (PCR) from a plasmid library made from pituitary RNA. Complete cDNA cloning was achieved by carrying out two PCR reactions: one with an upstream sense primer plus the universal sequencing primer, located downstream of the poly(A) sequence of the cDNA in the plasmid vector, to amplify the downstream portion of the cDNA; the other with a downstream antisense primer plus the reverse-sequencing primer, located upstream of the very 5' end of the cDNA sense strand in the plasmid vector, to amplify the upstream portion of the cDNA. The two amplified fragments overlapping about 70 bp. Nucleotide sequence analysis revealed that the catfish GTH alpha-subunit was 658 bp encoding 116 amino acids and harboring a 5' nontranslated region (NTR) of 42 bp and a 3' NTR of 265 bp. The deduced amino acid sequence of the catfish GTH alpha-subunit is highly conserved with those from other cloned teleost GTH alpha-subunits. The GTH alpha-subunit was highly expressed even before induction for ovulation in females during spawning season. Administration of carp pituitary extract (a spawning-inducing reagent) induced only 1.4-fold higher expression of the GTH alpha-subunit RNA, but included very rapid egg maturation and ovulation. This unexpected result indicated that the GTH alpha-subunit may not be the limiting factor for ovulation and spawning, which may be regulated by the change of proportional coupling of the GTH alpha-subunit with specific beta-subunit during hormone-induced ovulation.