Wu Y, Cutting G R
Institute of Genetic Medicine, The Johns Hopkins University School of Medicine, 600 N. Wolfe St., Baltimore, MD 20287, USA.
Brain Res. 2001 Aug 31;912(1):1-8. doi: 10.1016/s0006-8993(01)02433-7.
In this study, we compared the temporal expression pattern of four retinal genes; rho1 and rho2 that encode subunits of GABA(c) receptors, L7 that encodes Purkinje cell protein and CRX that encodes the cone-rod homeobox transcription factor. A reverse-transcription-polymerase chain reaction (RT-PCR) strategy that generated a linear correlation between the amount of retinal RNA and the amount of amplified product was used to quantify transcripts from each gene. Results with this method showed that the rho1 and L7 have similar developmental patterns. Both exhibit basal level expression before P7. From P7 to P20, the RNA levels for both genes were increased about 12-fold. After P20, the RNA levels remained unchanged. Compared to rho1 and L7, expression of rho2 began later, since the rho2 RNA could not be detected until P10. At P10, the rho2 RNA level was about 10% of its level at P35. Expression of rho2 reached its peak at a later developmental stage compared to that of rho1 and L7. The different temporal patterns were confirmed by co-amplification of rho1, rho2, and L7 in a single PCR tube. CRX RNA was detected at embryonic day 15 (E15) and increased progressively, in agreement with a prior study using in situ hybridization. These data, combined with evidence that the tissue distribution of rho1 and L7 RNA in the CNS are similar, indicates that rho1 and L7 may share common transcriptional regulatory elements. Furthermore, the difference in the timing of rho subunit expression suggests that the subunit composition of GABA(c) receptors vary during retinal development.
在本研究中，我们比较了四个视网膜基因的时序表达模式；编码γ-氨基丁酸C型（GABA(c)）受体亚基的rho1和rho2、编码浦肯野细胞蛋白的L7以及编码视锥-视杆同源框转录因子的CRX。我们采用了一种逆转录-聚合酶链反应（RT-PCR）策略，该策略在视网膜RNA量与扩增产物量之间产生线性相关性，用于定量每个基因的转录本。该方法的结果表明，rho1和L7具有相似的发育模式。两者在出生后第7天（P7）之前均表现出基础水平的表达。从P7到P20，两个基因的RNA水平均增加了约12倍。P20之后，RNA水平保持不变。与rho1和L7相比，rho2的表达开始较晚，因为直到P10才能检测到rho2 RNA。在P10时，rho2 RNA水平约为其在P35时水平的10%。与rho1和L7相比，rho2的表达在较晚的发育阶段达到峰值。通过在单个PCR管中共扩增rho1、rho2和L7，证实了不同的时序模式。在胚胎第15天（E15）检测到CRX RNA，并且其逐渐增加，这与先前使用原位杂交的研究结果一致。这些数据，结合rho1和L7 RNA在中枢神经系统中的组织分布相似的证据，表明rho1和L7可能共享共同的转录调控元件。此外，rho亚基表达时间的差异表明，GABA(c)受体的亚基组成在视网膜发育过程中有所不同。
