The highly conserved domain of the Caulobacter McpA chemoreceptor is required for its polar localization
The highly conserved domain of the Caulobacter McpA chemoreceptor is required for its polar localization
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DOI：
10.1046/j.1365-2958.2001.02476.x
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发表时间：
2001-06-01
影响因子：
3.6
通讯作者：
Alley, MRK
中科院分区：
文献类型：
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作者：
Alley, MRK
我们将GFP融合到MCPA的C-末端，研究了化学受体在新月桂枝杆菌中的极性定位。全长的MCPA-GFP融合是极化定位和甲基化的。甲基化依赖于存在于MCPA操纵子中的化学受体甲基转移酶(CHER)和化学受体甲酯酶(CHEB)基因。构建了MCPA的C端和内部缺失，并将其与GFP的N端融合，以识别极性定位所需的结构域。当R1甲基化结构域被删除时，MCPA-GFP融合仍然是极性定位的，这表明该结构域对于极性定位是必要的。然而，当参与与CHEW相互作用的高度保守结构域(HCD)通过内部缺失或C-末端缺失被删除时，所得到的MCPA-GFP融合完全离域。当含有Chew和Chea同源物的MCPA操纵子被删除时，全长MCPA-GFP融合被离域。虽然MCPA-GFP的极性定位需要额外的趋化基因，但不需要单个极性鞭毛的存在。然而，在丝状细胞中，MCPA-GFP融合在细胞中间位置被观察到，这是在新月浑圆线虫FliF突变体中常见的。
We have fused GFP to the C-terminus of McpA to study chemoreceptor polar localization in Caulobacter crescentus. The full-length McpA-GFP fusion is polarly localized and methylated. The methylation is dependent on the chemoreceptor methyltransferase (cheR) and chemoreceptor methylesterase (cheB) genes present in the mcpA operon. C-terminal and internal deletions of McpA were constructed and fused to the N-terminus of GFP to identify the domains required for polar localization. When the R1 methylation domain was deleted, the McpA-GFP fusion was still polarly localized, suggesting that this domain is dispensable for polar localization. However, when the highly conserved domain (HCD), which is involved in interacting with CheW, was deleted either by an internal deletion or C-terminal deletion, the resulting McpA-GFP fusions were completely delocalized. When the mcpA operon, which contains the cheW and cheA homologues, was deleted, the full-length McpA-GFP fusion was delocalized. Although additional chemotaxis genes are required for the polar localization of McpA-GFP, the presence of the single polar flagellum is not required. However, in filamentous cells, which are frequently found in C. crescentus fliF mutants, the McpA-GFP fusion was observed at mid-cell positions.