rhomboid mediates specification of blue- and green-sensitive R8 photoreceptor cells in Drosophila.
rhomboid mediates specification of blue- and green-sensitive R8 photoreceptor cells in Drosophila.
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DOI：
10.1523/jneurosci.5988-08.2009
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发表时间：
2009-03-04
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影响因子：
--
通讯作者：
Britt SG
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文献类型：
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作者：
Birkholz DA;Chou WH;Phistry MM;Britt SG
色觉是基于视网膜光感受器的不同颜色敏感性，然而控制光感受器细胞分化和指定颜色敏感性的发育程序知之甚少。在果蝇中，越来越多的证据表明，单个小眼内的R8细胞的颜色敏感性受到来自相邻R7细胞的诱导信号的调节。我们以前研究了视网膜图案缺陷的Scutoid突变体，这是由于菱形表达中断。在这里，我们表明，菱形块的损失的诱导Rh5的表达和菱形的错误表达导致不适当的诱导Rh5。这些作用是特定于菱形的，因为其paramyroughoid既不是诱导Rh5表达所必需的，也不足以诱导Rh5表达。我们发现，菱形是所需的细胞自主内的R8感光细胞和非自主的其他地方在眼睛的Rh5诱导。有趣的是，我们发现表皮生长因子受体也是Rh5诱导所必需的，并且其激活足以挽救菱形突变体中Rh5诱导的丧失。这表明菱形可能在R8细胞中起作用以激活R7细胞中的表皮生长因子受体信号传导并促进其分化为信号传导活性状态。
Color vision is based on the differential color sensitivity of retinal photoreceptors, however the developmental programs that control photoreceptor cell differentiation and specify color sensitivity are poorly understood. In Drosophila there is growing evidence that the color sensitivity of the R8 cell within an individual ommatidium is regulated by an inductive signal from the adjacent R7 cell. We previously examined the retinal patterning defect in Scutoid mutants, which results from a disruption of rhomboid expression. Here we show that loss of rhomboid blocks the induction of Rh5 expression and misexpression of rhomboid leads to the inappropriate induction of Rh5. These effects are specific to rhomboid, as its paralogue roughoid is neither required nor sufficient for the induction of Rh5 expression. We show that rhomboid is required cell-autonomously within the R8 photoreceptor cells and non-autonomously elsewhere in the eye for Rh5 induction. Interestingly, we found that the Epidermal Growth Factor Receptor is also required for Rh5 induction, and its activation is sufficient to rescue the loss of Rh5 induction in a rhomboid mutant. This suggests that rhomboid may function in R8 cells to activate Epidermal Growth Factor Receptor signaling in R7 cells and promote their differentiation to a signaling competent state.