牙鲆中Dicer基因的鉴定与表达

Identification and expression analysis of Dicer gene from Paralichthys olivaceus

通过PCR技术,从牙鲆(Paralichtys olvaceus)总RNA中克隆了牙鲆Dicer基因序列,该序列全长6 585bp,包括5 691 bp的开放阅读框,编码1 896个氨基酸。在多个物种间的蛋白序列对比中,牙鲆Dicer与其它物种的同源性平均高达78%,与尼罗罗非鱼(Oreochromis niloticus)同源性最高达到89%;在进化树分析中,牙鲆Dicer与其它鱼类Dicer聚集一支。荧光定量PCR显示,牙鲆Dicer基因在牙鲆大脑里的表达最高。同样的,在牙鲆胚胎和仔鱼早期发育阶段里也发现了相对高水平的Dicer mRNA表达。在用甲状腺激素(TH)处理过程中发现,牙鲆Dicer基因在用TH处理后17 dph的表达最高。本研究预测了牙鲆Dicer在牙鲆发育和变态过程中扮演的重要角色,为进一步阐明Dicer在牙鲆变态发育中的功能奠定了基础。

Dicer gene from Paralichthys olivaceus was cloned by PCR, and the gene sequence was 6 585 bp, including a 5 691 bp open reading frame （ ORF）, encoding a polypeptide of 1 896 amino acids. The Dicer gene was highly homologous with amino acid sequence in other fish through phylogency analysis. BLAST analysis indicated that the Dicer from P. olivaceus showed an average homology of 78% to other species, and the highest 89% was found in Oreochromis niloticus. Real-time quantitative PCR revealed that the Dicer mRNA from P. olivaceus was expressed. The highest level was detected in the tissue of brain and relatively high level in embryonic and early larval stages. The expression of Dicer mRNA was highly up-regulated by thyroid hormone （TH） at 17 dph and 23 dph. The findings indicated that Dicer played an important role in development and metabolism of P. olivaceus, providing the basic information for further study on the role of Dicer gene in the development of P. olivaceus.