大鼠松果体N-乙酰转移酶基因的昼夜节律性表达

Circadian Expression of the Arylalkylamine N-acetyltransferase Gene in the Rat Pineal Gland

探讨12 h光照、12 h黑暗交替(LD)光制下松果体N-乙酰转移酶(NAT)基因的昼夜节律性表达。SD大鼠在LD光制下饲养4周后,在一昼夜内每隔4h采集一组松果体组织,提取总RNA,进行竞争性定量RT-PCR,测定不同昼夜时点(ZT)样品中NAT基因mRNA的相对表达量。用余弦函数获取节律参数,并经振幅检验分析是否存在昼夜节律。结果表明松果体NAT基因mRNA表达呈现昼夜节律性振荡(P<0.05),峰值(mRNA水平为1.07±0.23)和谷值(mRNA水平为0.61±0.15)分别位于ZT16和ZT4,峰值相位-241.80±14.94,振幅0.23±0.13,中值0.84±0.11。证实LD光制下松果体NAT基因存在明显的昼低夜高节律性表达。

The circadian expression of the Arylalkylamine N-acetyltransferase (NAT) gene in the ra1 pineal gland was examined under the 12 h-light and 12 h-dark cycle condition (LD). 36 SD rats housed under the light regime of LD for four weeks were sampled for the pineal gland once every 4 hours in a circadian day. The total RNA was extracted from the samples and the semiquantitative reverse transcription poly merase chain reaction (RT-PCR) was used to determine the temporal changes in mRNA level of the NAT gene during different zeitgeber times (ZT). The data parameters were analysed by both the cosine function software and the amplitude F test to reveal the circadian rhythm. The NAT mRNA level in the pineal gland showed a significantly circadian oscillation (P<0. 05), with the peak (level is 1. 07±0. 23) at ZT16 and trough (level is 0. 61±0. 15) at ZT4. The parameter values of the peak phase, amplitude and mesor were-241. 80±14. 94, 0. 23±0. 13 and 0. 84±0. 11, respectively. The findings demonstrate that the circadian expression of NAT gene in the pineal gland is weak during the daytime and robust at nighttime under LD condition.