Localization of Proteins to Different Layers and Regions of Bacillus subtilis Spore Coats
Localization of Proteins to Different Layers and Regions of Bacillus subtilis Spore Coats
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DOI：
10.1128/jb.01103-09
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发表时间：
2010-01-01
影响因子：
3.2
通讯作者：
Watabe, Kazuhito
中科院分区：
文献类型：
--
作者：
Imamura, Daisuke;Kuwana, Ritsuko;Watabe, Kazuhito
细菌孢子被包裹在多层的蛋白质外壳中，称为被毛。在枯草芽孢杆菌中，超过50种蛋白质参与孢子外壳组装，但这些蛋白质在孢子外壳中的位置知之甚少。在这里，我们描述了利用荧光显微镜估计孢子外壳中蛋白质融合到荧光蛋白位置的方法。我们的研究表明，CotD、CotF、CotT、GerQ、YaaH、YeeK、YmaG、YsnD和YxeE存在于内被毛中，CotA、CotB、CotC和YtxO存在于外被毛中。CotZ和CgeA出现在孢子外壳的最外层，在前孢子的近极母细胞中含量较多，而CotA和CotC在前孢子的远极母细胞中含量较多。在前孢子从母细胞释放之前的孢子囊和释放后的成熟孢子中都观察到这些极性定位。此外，在孢子中央观察到CotB呈环状或螺旋状结构。这种结构的形成需要cotG的表达。因此，我们得出结论，孢子外壳不仅是一个多层组装体，而且还表现出特定蛋白质的不均匀空间分布。
Bacterial spores are encased in a multilayered proteinaceous shell known as the coat. In Bacillus subtilis, over 50 proteins are involved in spore coat assembly but the locations of these proteins in the spore coat are poorly understood. Here, we describe methods to estimate the positions of protein fusions to fluorescent proteins in the spore coat by using fluorescence microscopy. Our investigation suggested that CotD, CotF, CotT, GerQ, YaaH, YeeK, YmaG, YsnD, and YxeE are present in the inner coat and that CotA, CotB, CotC, and YtxO reside in the outer coat. In addition, CotZ and CgeA appeared in the outermost layer of the spore coat and were more abundant at the mother cell proximal pole of the forespore, whereas CotA and CotC were more abundant at the mother cell distal pole of the forespore. These polar localizations were observed both in sporangia prior to the release of the forespore from the mother cell and in mature spores after release. Moreover, CotB was observed at the middle of the spore as a ring-or spiral-like structure. Formation of this structure required cotG expression. Thus, we conclude not only that the spore coat is a multilayered assembly but also that it exhibits uneven spatial distribution of particular proteins.