Crx基因的延迟表达与Chx10缺陷型视网膜中的光感受器发育

Delayed expression of the Crx gene and photoreceptor development in the Chx10-deficient retina.

作者信息

Rutherford Adam D, Dhomen Nathalie, Smith Hazel K, Sowden Jane C

机构信息

Developmental Biology Unit, Institute of Child Health, University College London, London, United Kingdom.

出版信息

Invest Ophthalmol Vis Sci. 2004 Feb;45(2):375-84. doi: 10.1167/iovs.03-0332.

DOI:10.1167/iovs.03-0332

PMID:14744875

Abstract

PURPOSE

The Chx10 homeobox gene is expressed in neural progenitor cells during retinal development. The absence of Chx10 causes microphthalmia in humans and in the mouse mutant ocular retardation. The purpose of this study was to examine how neuronal development is affected by absence of the Chx10 transcription factor in the mouse retina.

METHODS

Expression of transcription factor genes, Crx, Pou4f2, and Pax6, that mark specific cell types as they begin to differentiate was analyzed by RNA in situ hybridization of retina from wild-type and Chx10-null ocular retardation mice (Chx10(or-J/or-J)). RT-PCR analysis was used to compare expression of these genes and putative targets of Crx regulation. Photoreceptor development was analyzed by using peanut agglutinin (PNA)-rhodamine and blue cone opsin antibody to label cones and rhodopsin antibody to label rods.

RESULTS

The photoreceptor gene Crx, normally expressed during embryonic retinal development, was not detected in the embryonic mutant retina, but was expressed after birth. Expression of the targets of Crx regulation, rhodopsin, peripherin, rod phosphodiesterase beta (Pdeb), and arrestin, with the exception of interphotoreceptor retinoid binding protein (Irbp), was delayed in the Chx10(or-J/or-J) retina. Rhodopsin localization in rod outer segments was also delayed. By contrast, temporal and spatial expression of Pou4f2 and Pax6 in developing ganglion and amacrine cells and PNA and blue opsin in developing cone cells was relatively normal in the mutant.

CONCLUSIONS

Delay of the normal temporal expression of genes essential for photoreceptor disc morphogenesis leads to failure of correct rod and cone outer segment formation in the Chx10(or-J/or-J) mutant retina. In addition, the absence of Chx10 appears to affect the development of late-born cells more than that of early-born cells, in that a low number of rods develops, whereas formation of ganglion, amacrine, and cone cells is relatively unaffected.

摘要

目的

Chx10同源盒基因在视网膜发育过程中于神经祖细胞中表达。Chx10缺失会导致人类小眼球症以及小鼠突变体眼发育迟缓。本研究的目的是检测小鼠视网膜中Chx10转录因子缺失如何影响神经元发育。

方法

通过对野生型和Chx10基因敲除的眼发育迟缓小鼠（Chx10(or-J/or-J)）的视网膜进行RNA原位杂交，分析标记特定细胞类型开始分化时的转录因子基因Crx、Pou4f2和Pax6的表达。采用逆转录聚合酶链反应（RT-PCR）分析来比较这些基因以及Crx调控的假定靶标的表达。利用花生凝集素（PNA）-罗丹明和蓝锥视蛋白抗体标记视锥细胞，用视紫红质抗体标记视杆细胞，分析光感受器的发育。

结果

在胚胎突变体视网膜中未检测到通常在胚胎视网膜发育期间表达的光感受器基因Crx，但出生后有表达。除视网膜间视黄醇结合蛋白（Irbp）外，Chx10(or-J/or-J)视网膜中Crx调控靶标视紫红质、外周蛋白、视杆磷酸二酯酶β（Pdeb）和抑制蛋白的表达延迟。视紫红质在视杆外段的定位也延迟。相比之下，突变体中发育中的神经节细胞和无长突细胞中Pou4f2和Pax6的时空表达以及发育中的视锥细胞中PNA和蓝视蛋白的时空表达相对正常。