小鼠纹状体时钟基因表达的生后发育

Postnatal ontogenesis of molecular clock genes in mouse striatum

目的研究小鼠纹状体中时钟基因表达的生后发育。方法选新生早期（P3）、断奶前期（P14）和成年（P60）小鼠，光照1h[01Hour-After-Light-On（HALO）=09：00]起取纹状体，连续24h取材，取材时间间隔6h。实时定量RT—PCR检测时钟基因Bmall，Clock，Cryl，Perl和Rev-erbamRNA水平。结果P3组中，5种时钟基因表达均无明显波动；P14组仅有Rev-erb αmRNA表达随时间变化（P=0．027），表达高峰在19-01HALO；而P60组，各基因表达均表现明显波动[Bmall（P=0．004）、Clock（P=0．004）、Perl（P=0．004）、Rev—erbcL（P=0．004）]，Bmall，Clock和Cryl的高峰在01HALO，Perl和Rev—erbct分别在13HALO和07HALO。此外每种基因的总体表达水平出生后也呈动态变化，Bmall，Clock，Perl和Rev—erb表达丰度随发育而增加，P3组〈P14〈P60；Cryl则在P3和P60表达相近，P14表达较低。P3和P14组Bmall、Clock分别为1．74和1．16，表明发育早期Bmall的表达高于Clock。结论纹状体时钟基因在出生后逐渐发育，最终形成成年小鼠中调节纹状体生物节律的、功能完善的网络。

Objective To study the mRNA expression profiles of clock genes in mouse striatum during postnatal ontogenesis. Methods C57 BL/6J male mice were grouped with development stages：early postnatal stage （postnatal day 3 ） , pre-weaning stage （postnatal day 14） and aduh （postnatal day 60 ）. Animals were transferred into constant darkness for 24 hours and sacrificed at 6 h intervals beginning at 09：00 h local time （01 HALO = Hours after Light Onset）. The striatum were dissected out. 24h mRNA oscillations of 5 principle clock genes （Bmall, Clock,Cryl, Perl and Rev-erbα） were examined using real time PCR. Results At P3, no daily oscillation was found for all clock genes. At P14 ,a significant time effect was identified only for Rev-erb α （P= 0. 027） ,with peak value at 19 to 01 HALO. At P60,the daily oscillations of these clock genes were at least borderline significant （ Bmall ： P = 0. 004, Clock ： P = 0.004, Perl ： P = 0. 004, Rev-erbcα ： P = 0. 004 ）, with peak time at 01 HALO for Bmall ,Clock and Cryl ; at 13 HALO for Perl ; and at 07 HALO for Rev-erboα. In addition,the overall mean mRNA levels of these clock genes also underwent a dynamic change postnatally. For Bmall, Clock,Per1 and Rev-erbα,the expression level increased throughout the postnatal ontogenesis from P3,P14 to P60. For Cryl, however,the abundance at P3 and P60 were similar while that at P14 was much lower. Conclusion The striatal molecular clock machinery, although works efficiently in adult, develops gradually after birth in mice.