Two novel proteins, PopB, which has functional nuclear localization signals, and PopC, which has a large leucine-rich repeat domain, are secreted through the Hrp-secretion apparatus of Ralstonia solanacearum
Two novel proteins, PopB, which has functional nuclear localization signals, and PopC, which has a large leucine-rich repeat domain, are secreted through the Hrp-secretion apparatus of Ralstonia solanacearum
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DOI：
10.1046/j.1365-2958.2000.01870.x
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发表时间：
2000-04-01
影响因子：
3.6
通讯作者：
Arlat, M
中科院分区：
文献类型：
--
作者：
Guéneron, M;Timmers, ACJ;Arlat, M
青枯雷尔氏菌hrp基因簇编码PopA1（一种过敏反应样诱导蛋白）分泌所必需的III型分泌途径的组分。在本研究中，我们表明，其他几个HRP分泌的蛋白可以检测到生长的野生型细菌在基本培养基中的存在下，刚果红。这些蛋白质中的两种，PopB和PopC，由位于popA下游的基因编码，并与popA构成操纵子。popABC突变体保留了野生型在宿主中引起疾病和在非宿主上引起过敏反应的能力。popABC操纵子的表达受hrpB调控基因控制，并在与拟南芥细胞悬浮液共培养时被诱导。这种植物细胞特异性诱导依赖于PrhA，一种植物特异性信号的推定受体。向生长培养基中加入刚果红不会改变popABC操纵子的转录，并且PopB和PopC的细胞内库在不存在或存在刚果红的情况下非常相似。初步数据表明，刚果红稳定细胞外介质中的分泌蛋白。PopB是一种由173个氨基酸组成的碱性蛋白，含有功能性的二分核定位信号。PopC是一种由1024个氨基酸组成的蛋白质，携带22个串联的富含亮氨酸的重复序列（LRR）。该蛋白质的LRR结构域形成与预测的真核细胞质LRR一致性完全匹配的一致性。我们认为PopB和PopC可能通过Hrp途径转运到植物细胞中。
The Ralstonia solanacearum hrp gene cluster codes for components of a type III secretion pathway necessary for the secretion of PopA1, a hypersensitive response-like elicitor protein. In the present study, we show that several other Hrp-secreted proteins can be detected by growing wild-type bacteria in minimal medium in the presence of Congo red. Two of these proteins, PopB and PopC, are encoded by genes located downstream of popA and constitute an operon with popA. popABC mutants retain the wild-type ability to cause disease in hosts and to elicit the hypersensitive response on non-hosts. Expression of the popABC operon is controlled by the hrpB regulatory gene and is induced upon co-culture with Arabidopsis cell suspensions. This plant cell-specific induction depends on PrhA, a putative receptor for plant specific signal(s). The transcription of the popABC operon is not modified by the addition of Congo red to the growth medium and the intracellular pools of PopB and PopC are very similar in the absence or presence of Congo red. Preliminary data suggest that Congo red stabilizes secreted proteins in the extracellular medium. PopB is a 173-amino-acid-basic protein that contains a functional bipartite nuclear localization signal. PopC is a 1024-amino-acid protein that carries 22 tandem leucine-rich repeats (LRR). The LRR domain of this protein forms a consensus that perfectly matches the predicted eukaryotic cytoplasmic LRR consensus. We propose that PopB and PopC may be translocated into plant cells via the Hrp pathway.