The endoplasmic reticulum is partitioned asymmetrically during mitosis before cell fate selection in proneuronal cells in the early Drosophila embryo.
The endoplasmic reticulum is partitioned asymmetrically during mitosis before cell fate selection in proneuronal cells in the early Drosophila embryo.
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DOI：
10.1091/mbc.e16-09-0690
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发表时间：
2017-06-01
影响因子：
3.3
通讯作者：
Riggs B
中科院分区：
文献类型：
--
作者：
Eritano AS;Altamirano A;Beyeler S;Gaytan N;Velasquez M;Riggs B
在早期的果蝇胚胎中，上皮细胞开始接受细胞命运。在原肠胚形成时，在细胞命运选择之前，在对称分裂的细胞群中存在内质网的不对称分配。这些结果突出了不对称分裂前细胞器分布的变化。不对称细胞分裂是产生细胞多样性的主要机制，它依赖于细胞命运决定因子的正确分配。然而，这些决定因素的传递和定位机制知之甚少，启动不对称细胞分裂的上游信号也是未知的。在这里，我们报告说，内质网（ER）是不对称的分区上皮细胞有丝分裂前分层和选择的前神经细胞的命运在早期果蝇胚胎。在原肠胚形成开始时，ER在胚胎的前端不对称地分裂成一群异步分裂的细胞。我们发现，这种不对称分裂的ER依赖于高度保守的ER膜蛋白Jagunal（Jagn）。在原肠胚形成开始之前RNA抑制jagn破坏了ER的这种不对称分裂。此外，在分层的胚胎神经母细胞中，jagn缺陷的胚胎在顶基纺锤体方向上显示缺陷。我们的研究结果描述了一个模型，在该模型中，一个细胞器被分配不对称的，否则对称分裂的细胞群体上游的细胞命运的决定和更新以前的模型纺锤体为基础的选择细胞的命运在有丝分裂。
In the early Drosophila embryo, epithelial cells begin to adopt a cell fate. At gastrulation, there is an asymmetric partitioning of the endoplasmic reticulum in a symmetrically dividing cell population before cell fate selection. These results highlight the changes in organelle distribution before asymmetric divisions. Asymmetric cell division is the primary mechanism to generate cellular diversity, and it relies on the correct partitioning of cell fate determinants. However, the mechanism by which these determinants are delivered and positioned is poorly understood, and the upstream signal to initiate asymmetric cell division is unknown. Here we report that the endoplasmic reticulum (ER) is asymmetrically partitioned during mitosis in epithelial cells just before delamination and selection of a proneural cell fate in the early Drosophila embryo. At the start of gastrulation, the ER divides asymmetrically into a population of asynchronously dividing cells at the anterior end of the embryo. We found that this asymmetric division of the ER depends on the highly conserved ER membrane protein Jagunal (Jagn). RNA inhibition of jagn just before the start of gastrulation disrupts this asymmetric division of the ER. In addition, jagn-deficient embryos display defects in apical-basal spindle orientation in delaminated embryonic neuroblasts. Our results describe a model in which an organelle is partitioned asymmetrically in an otherwise symmetrically dividing cell population just upstream of cell fate determination and updates previous models of spindle-based selection of cell fate during mitosis.