Hong D H, Pawlyk B S, Shang J, Sandberg M A, Berson E L, Li T
Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA.
Proc Natl Acad Sci U S A. 2000 Mar 28;97(7):3649-54. doi: 10.1073/pnas.97.7.3649.
The X-linked RP3 locus codes for retinitis pigmentosa GTPase regulator (RPGR), a protein of unknown function with sequence homology to the guanine nucleotide exchange factor for Ran GTPase. We created an RPGR-deficient murine model by gene knockout. In the mutant mice, cone photoreceptors exhibit ectopic localization of cone opsins in the cell body and synapses and rod photoreceptors have a reduced level of rhodopsin. Subsequently, both cone and rod photoreceptors degenerate. RPGR was found normally localized to the connecting cilia of rod and cone photoreceptors. These data point to a role for RPGR in maintaining the polarized protein distribution across the connecting cilium by facilitating directional transport or restricting redistribution. The function of RPGR is essential for the long-term maintenance of photoreceptor viability.
X连锁的RP3基因座编码视网膜色素变性GTP酶调节蛋白(RPGR),这是一种功能未知的蛋白质,其序列与Ran GTP酶的鸟嘌呤核苷酸交换因子具有同源性。我们通过基因敲除创建了一个RPGR缺陷型小鼠模型。在突变小鼠中,视锥光感受器在细胞体和突触中表现出视锥视蛋白的异位定位,而视杆光感受器的视紫红质水平降低。随后,视锥和视杆光感受器均发生退化。发现RPGR正常定位于视杆和视锥光感受器的连接纤毛。这些数据表明RPGR通过促进定向运输或限制重新分布,在维持连接纤毛上的极化蛋白分布中发挥作用。RPGR的功能对于光感受器活力的长期维持至关重要。