Gu P L, Chan S M
Department of Zoology, The University of Hong Kong, Hong Kong.
Mol Mar Biol Biotechnol. 1998 Sep;7(3):214-20.
Degenerate primers were designed from the amino acid sequence of the neuropeptide Pej-SGP-IV of the shrimp Penaeus japonicus. Reverse transcriptase-polymerase chain reaction (RT-PCR) was performed using eyestalk complementary DNA of the sand shrimp Metapenaeus ensis. A partial cDNA that codes for a protein homologous to the neuropeptide Pej-SG-IV was cloned. The partial cDNA was used as a probe to screen the eyestalk cDNA library. Several cDNA clones with nucleotide sequence identical to the partial cDNA were isolated. The largest cDNA is 957 bp with an open reading frame consisting of a coding sequence 315 bp in length. The deduced amino acid of the neuropeptide consists of 77 amino acids and is preceded by a signal peptide of 28 amino acids. Because the deduced amino acid sequence of the shrimp cDNA is highly homologous to the Pej-SGP-IV of P. japonicus (which is molt inhibiting) and to other crustaceans' molt-inhibiting hormones (MIHs), the shrimp neuropeptide is tentatively called MeMIH. Northern blot analysis and RT-PCR showed that MeMIH is expressed in the postmolt, intermolt, and premolt stages of the shrimp eyestalks and the brain. Moreover, RNA message can also be detected in the nervous tissues of newly developed larvae. MeMIH is, however, not found in the muscle, swimming leg, and hepatopancreas. Results from genomic Southern blot analysis and amplification of the shrimp genomic DNA by polymerase chain reaction (PCR) suggest that a single copy of the MIH gene is present in the genome. The structural organization of the gene for the shrimp putative MIH is similar to that of the crab Charybdis feriatus.
根据日本对虾神经肽Pej - SGP - IV的氨基酸序列设计简并引物。利用中国明对虾眼柄互补DNA进行逆转录聚合酶链反应（RT - PCR）。克隆了一个编码与神经肽Pej - SG - IV同源蛋白的部分cDNA。该部分cDNA用作探针筛选眼柄cDNA文库。分离出几个核苷酸序列与该部分cDNA相同的cDNA克隆。最大的cDNA为957 bp，开放阅读框由一个长度为315 bp的编码序列组成。推导的神经肽氨基酸由77个氨基酸组成，前面有一个28个氨基酸的信号肽。由于推导的虾cDNA氨基酸序列与日本对虾的Pej - SGP - IV（具有蜕皮抑制作用）以及其他甲壳类动物的蜕皮抑制激素（MIHs）高度同源，因此该虾神经肽暂称为MeMIH。Northern印迹分析和RT - PCR表明MeMIH在虾眼柄和脑的蜕皮后期、蜕皮间期和蜕皮前期均有表达。此外，在新发育幼虫的神经组织中也能检测到RNA信息。然而，在肌肉、游泳足和肝胰腺中未发现MeMIH。基因组Southern印迹分析结果以及通过聚合酶链反应（PCR）扩增虾基因组DNA表明，基因组中存在MIH基因的单拷贝。推测的虾MIH基因的结构组织与锈斑蟳的相似。
