鲢神经肽Y基因的克隆及其在禁食.恢复投喂条件下的表达特征分析

CLONING AND EXPRESSION OF NPY IN THE SILVER CARP(HYPOPHTHALMICHTHYS MOLITRIX) DURING FASTING AND REFEEDING

为深入研究神经肽Y对鲢摄食活动的调节作用,研究利用同源克隆方法获得鲢NPY基因cDNA全长序列,并检测在禁食.恢复投喂条件下,NPY在脑和肝脏中的表达情况.结果表明:鲢NPY基因cDNA全长782 bp,包括5'端非翻译区68 bp,3'端非翻译区423 bp,开放阅读框291 bp,编码96个氨基酸;氨基酸相似性比较和系统进化分析结果显示NPY较为保守;NPY在所检测的13个组织中均有表达,并且在脑垂体中表达量最大;禁食导致NPY mRNA在脑中的表达量显著上升,恢复投喂6h后下降到基本水平,表明NPY鲢摄食有促进作用;在肝脏中,禁食前5天NPY mRNA表达量显著上升,禁食第7天急剧下降,恢复投喂4h后下降到基本水平;NPY mRNA在脑和肝脏中的表达具有组织差异性,其在肝脏中的具体作用机制有待进一步研究.研究结果为探讨NPY鲢中的生物学功能和在遗传育种中的作用提供了理论依据。

NPYplays a significant role in regulating food intake and energy metabolism in teleosts. To understand the biological role of NPY in the silver carp （Hypophthalmichthys molitrix）, in this study we determined the full-length cDNA sequence of NPYand investigated the effect of fasting and refeeding on the level of NPYmRNA in the brain and the liver. The full cDNA sequence of NPY consisted of 782 bp, including a 291 bp open reading frame that potentially encodes 96 amino acids, a 68 bp 5＇-untranslated region and a 423 bp Y-untranslated region. Our study on the similarity of the amino acid sequence and the phylogenetic analysis of NPY demonstrated that the NPY gene was relatively con- servative during the molecular evolution. The mRNA of NPYwas ubiquitously expressed in all the tested tissues and especially abundant in the pituitary. In the brain, the expression of NPY mRNA increased significantly during fasting, and then decreased to the basal level at 6h after refeeding, which indicated that NPY could boost the food intake of the silver carp. In the liver, the expression of NPY mRNA increased significantly until 5d after fasting, then decreased sharply on the 7th day, and finally returned to the basal level at 4h after refeeding. NPY was expressed in a tissue-specific pattern in both the brain and the liver. However, the function of NPY in the liver needs further study. Our study provided insights into the biological roles of NPY in the silver carp.