Patterning of the R7 and R8 photoreceptor cells of Drosophila: evidence for induced and default cell-fate specification.
Patterning of the R7 and R8 photoreceptor cells of Drosophila: evidence for induced and default cell-fate specification.
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发表时间：
1999-02
期刊：
影响因子：
4.6
通讯作者：
W. Chou;A. Huber;J. Bentrop;S. Schulz;K. Schwab;L. Chadwell;R. Paulsen;S. Britt
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文献类型：
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作者：
W. Chou;A. Huber;J. Bentrop;S. Schulz;K. Schwab;L. Chadwell;R. Paulsen;S. Britt
果蝇复眼R7和R8感光细胞视蛋白基因表达高度协调。我们已经发现，R8细胞特异性Rh 5和Rh 6视蛋白在非重叠的R8细胞组中表达，与单个小眼的R7细胞中的Rh 3和Rh 4以精确的成对方式表达。在sevenless、boss或sina突变体中去除R7细胞，破坏了Rh 5的表达，并显著增加了表达Rh 6的R8细胞的数量。这表明Rh 5的表达可能是由表达Rh 3的R7细胞诱导的，而Rh 6表达最有可能是R8细胞的默认状态。我们发现，视蛋白基因在R7和R8细胞中的成对表达以sevenless和boss独立的方式发生。此外，我们发现，Rh 3-和Rh 4-表达R7细胞的生成可以在不存在R8细胞的情况下发生。这些结果表明，在R7细胞中的视蛋白表达的规范可能会自主发生，而R7感光细胞可能是负责调节诱导和默认的细胞命运在R8细胞之间的二元发育开关。
Opsin gene expression in the R7 and R8 photoreceptor cells of the Drosophila compound eye is highly coordinated. We have found that the R8 cell specific Rh5 and Rh6 opsins are expressed in non-overlapping sets of R8 cells, in a precise pairwise fashion with Rh3 and Rh4 in the R7 cells of individual ommatidia. Removal of the R7 cells in sevenless, boss or sina mutants, disrupts Rh5 expression and dramatically increases the number of Rh6-expressing R8 cells. This suggests that the expression of Rh5 may be induced by an Rh3-expressing R7 cell, whereas Rh6 expression is most likely a default state of the R8 cell. We found that the paired expression of opsin genes in the R7 and R8 cells occurs in a sevenless and boss independent manner. Furthermore, we found that the generation of both Rh3- and Rh4-expressing R7 cells can occur in the absence of an R8 cell. These results suggest that the specification of opsin expression in the R7 cells may occur autonomously, whereas the R7 photoreceptor cell may be responsible for regulating a binary developmental switch between induced and default cell-fates in the R8 cell.