A role for extra macrochaetae downstream of Notch in follicle cell differentiation
A role for extra macrochaetae downstream of Notch in follicle cell differentiation
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DOI：
10.1242/dev.01442
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发表时间：
2004-12-01
期刊：
影响因子：
4.6
通讯作者：
Montell, DJ
中科院分区：
文献类型：
--
作者：
Adam, JC;Montell, DJ
果蝇卵巢为研究体细胞分化为特定细胞类型的调控机制提供了一个模型系统。卵巢体细胞干细胞产生卵泡细胞，在早期分化过程中，卵泡细胞经历了双重选择。它们既可以成为围绕胚线形成卵室的上皮细胞(主体细胞)，也可以成为卵室两极的特殊细胞谱系。这一谱系继续形成两种细胞类型：极细胞和柄细胞。为了更好地理解这一选择是如何做出的，我们对影响毛囊细胞命运指定或分化的基因进行了筛选。我们发现编码螺旋-环-螺旋蛋白的Extra Macchaetae(EMC)是卵巢中Notch信号的下游效应器。EMC表达于生殖细胞中的增殖细胞以及主体毛囊细胞中。EMC在主体细胞中的表达是Notch依赖性的，位于主体上的EMC突变细胞不能分化。EMC在极性细胞和柄细胞的前体细胞中的表达减少，EMC的过度表达导致卵室融合，表明EMC是极性细胞和/或柄细胞的负调节因子。眼球缺失(EYA)是极性细胞和柄细胞命运的负调控因子，在主体细胞中表达EMC和Notch都是必需的。我们认为EMC在Notch下游和EYA上游发挥作用，调节主体细胞命运的指定和分化。
The Drosophila ovary provides a model system for studying the mechanisms that regulate the differentiation of somatic stem cells into specific cell types. Ovarian somatic stem cells produce follicle cells, which undergo a binary choice during early differentiation. They can become either epithelial cells that surround the germline to form an egg chamber ('main body cells') or a specialized cell lineage found at the poles of egg chambers. This lineage goes on to make two cell types: polar cells and stalk cells. To better understand how this choice is made, we carried out a screen for genes that affect follicle cell fate specification or differentiation. We identified extra macrochaetae (emc), which encodes a helix-loop-helix protein, as a downstream effector of Notch signaling in the ovary. EMC is expressed in proliferating cells in the germarium, as well as in the main body follicle cells. EMC expression in the main body cells is Notch dependent, and emc mutant cells located on the main body failed to differentiate. EMC expression is reduced in the precursors of the polar and stalk cells, and overexpression of EMC caused dramatic egg chamber fusions, indicating that EMC is a negative regulator of polar and/or stalk cells. EMC and Notch were both required in the main body cells for expression of Eyes Absent (EYA), a negative regulator of polar and stalk cell fate. We propose that EMC functions downstream of Notch and upstream of EYA to regulate main body cell fate specification and differentiation.