Specification of primary pigment cell and outer photoreceptor fates by BarH1 homeobox gene in the developing Drosophila eye
Specification of primary pigment cell and outer photoreceptor fates by BarH1 homeobox gene in the developing Drosophila eye
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DOI：
10.1006/dbio.1998.8959
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发表时间：
1998-08-15
影响因子：
2.7
通讯作者：
Saigo, K
中科院分区：
文献类型：
--
作者：
Hayashi, T;Kojima, T;Saigo, K
在发育中的果蝇眼睛中，BarH 1和BarH 2，成对的同源盒基因在R1/R6外部光感受器和初级色素细胞中表达，对于正常的眼睛形态发生是必需的。在这里，我们显示的证据表明，BarH 1异位表达的控制下的sevenless增强子（sev-BarH 1）导致两种类型的视锥细胞转化：前/后锥细胞转化为外部光感受器和赤道/极锥细胞转化为初级色素细胞。sev-BarH 1抑制R3/R4光感受器中粗糙同源盒基因的内源性表达，而在相当一部分的外部光感受器中，sev-BarH 1激活BarH 2同源盒基因。在视锥细胞转化产生的初级色素细胞中，视锥细胞特异性同源盒基因cut的表达被Bar同源盒基因的表达完全取代。额外的外感光细胞的形成被抑制和增强，分别通过降低活性的Ras/MAPK信号和剂量减少的yan，一个负调节的途径，表明酒吧同源框基因（细胞命运决定因素）和Ras/MAPK信号在眼睛发育之间的相互作用。(C)北京：科学出版社.
In the developing Drosophila eye, BarH1 and BarH2, paired homeobox genes expressed in R1/R6 outer photoreceptors and primary pigment cells, are essential for normal eye morphogenesis. Here, we show evidence that BarH1 ectopically expressed under the control of the sevenless enhancer (sev-BarH1) causes two types of cone cell transformation: transformation of anterior/posterior cone cells into outer photoreceptors and transformation of equatorial/polar cone cells into primary pigment cells. sev-BarH1repressed the endogenous expression of the rough homeobox gene in R3/R4 photoreceptors, while the BarH2 homeobox gene was activated by sev-BarH1 in an appreciable fraction of extra outer photoreceptors. In primary pigment cells generated by cone cell transformation, the expression of cut, a homeobox gene specific to cone cells, was completely replaced with that of Bar homeobox genes. Extra outer photoreceptor formation was suppressed and enhanced, respectively, by reducing the activity of Ras/MAPK signaling and by dosage reduction of yan, a negative regulator of the pathway, suggesting interactions between Bar homeobox genes (cell fate determinants) and Ras/MAPK signaling in eye development. (C) 1998 Academic Press.