Photoreceptor outer segment development in Xenopus laevis: influence of the pigment epithelium.
Photoreceptor outer segment development in Xenopus laevis: influence of the pigment epithelium.
复制标题
非洲爪蟾光感受器外节发育：色素上皮的影响。
DOI：
10.1006/dbio.1994.1076
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发表时间：
1994
影响因子：
2.7
通讯作者：
Hollyfield,JG
中科院分区：
文献类型：
--
作者：
Stiemke,MM;Landers,RA;al-Ubaidi,MR;Rayborn,ME;Hollyfield,JG
对非洲爪哇视网膜发育过程中视蛋白基因的表达、合成和光感受器外节形态进行了研究。视网膜残片是在胚胎31~46期活体发育过程中获得的，或在33/34期胚胎取出1、2或3天后，在有或没有包被色素上皮的情况下在体外发育。Opsin mRNA在33/34期检测到，转录水平上升到40期，并维持在这一水平直到46期。视黄素在37/38期首次被检测到，并在46期逐渐增加。发育不全的光感受器外节膜有时早在33/34期出现，在活体发育过程中逐渐增长，形成清晰的塌陷的膜囊(盘)堆叠。观察眼球在培养中的成熟度，以确定在活体和体外发育中的接近程度，以及在没有覆盖的色素上皮(PE)层的情况下，光感受器的分化能力。在PE存在的情况下，视蛋白mRNA和视蛋白含量在整个培养过程中稳步增加。培养1d后，纤毛短小，外节膜质含量极少。到第3天，外节分化的程度在形态上与活体发育的第43期相对应。在无PE存在的情况下，视蛋白mRNA水平在培养的3天内最低限度地升高。视素含量增加，但相对含量比在PE存在的情况下发育的视网膜中的含量低约50%。膜材料是精细的；然而，外部节段似乎是高度无序的，形成了螺纹状结构，而不是正常的堆叠的磁盘形态。这些结果表明，PE可能参与了视蛋白的转录和/或翻译水平的调节，也参与了视杆细胞外节膜的组织。
Opsin gene expression, synthesis, and photoreceptor outer segment morphology were evaluated during retinal development inXenopus laevis. Retinal rudiments were harvested duringin vivodevelopment from embryonic stages 31 through 46 or were allowed to developin vitroafter removal from stage 33/34 embryos for 1, 2, or 3 days either with or without an investing pigment epithelium. Opsin mRNA was detected at stage 33/34 and the transcript level increased until stage 40 and remained at this level through stage 46. Opsin was first detected at stage 37/38 and progressively increased through stage 46. Rudimentary photoreceptor outer segment membranes occasionally appeared as early as stage 33/34 and they gradually increased in length, forming well-defined stacks of collapsed membranous saccules (discs) duringin vivodevelopment. The maturation of eye rudiments in culture was followed to determine how closelyin vivoandin vitrodevelopment compare and to examine the ability of photoreceptors to differentiate when maintained in the absence of an overlying pigment epithelium (PE) layer. With the PE present, opsin mRNA as well as opsin content steadily increased over the entire culture period. After 1 day of culture, short cilia with minimal amounts of outer segment membranous material were present. By Day 3, the degree of outer segment differentiation corresponded morphologically to approximately stage 43 ofin vivodevelopment. When cultured in the absence of an investing PE, the opsin mRNA level increased minimally during the 3 days in culture. Opsin content increased, yet the relative amount was approximately 50% less than that present in retinas developing in the presence of the PE. Membranous material was elaborated; however, the outer segments appeared to be highly disorganized and formed whorl-like structures rather than the normal stacked disc morphology. These results suggest that the PE may be involved in regulating opsin at the transcriptional and/or translational levels and also participates in the organization of rod outer segment membranes.