Flavobacterium johnsoniae sprB Is Part of an Operon Spanning the Additional Gliding Motility Genes sprC, sprD, and sprF
Flavobacterium johnsoniae sprB Is Part of an Operon Spanning the Additional Gliding Motility Genes sprC, sprD, and sprF
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DOI：
10.1128/jb.01203-10
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发表时间：
2011-02-01
影响因子：
3.2
通讯作者：
McBride, Mark J.
中科院分区：
文献类型：
--
作者：
Rhodes, Ryan G.;Nelson, Shawn S.;McBride, Mark J.
约翰逊黄杆菌的细胞通过一种称为滑动运动的过程在表面上快速移动。Gld蛋白被认为包含推动细胞表面粘附素的滑动马达，例如669-kDa的SprB。一种新的蛋白质分泌装置称为Por分泌系统（PorSS）是需要装配的SprB细胞表面。遗传和分子分析表明，sprB是一个7基因操纵子跨越29.3 kbp的DNA的一部分。除了sprB之外，该操纵子的其他三个基因（sprC、sprD和sprF）也参与滑行。sprB、sprC、sprD和sprF的突变导致细胞不能在琼脂上形成扩展集落，但在湿封片的玻璃上表现出一定的运动性。SprF表现出与牙龈卟啉单胞菌PorP的一些相似性，牙龈卟啉单胞菌PorP是经由牙龈卟啉单胞菌PorSS分泌牙龈卟啉菌蛋白酶毒力因子所需的。F. johnsoniae sprF突变体产生SprB蛋白，但在SprB定位到细胞表面方面有缺陷，表明SprF在SprB分泌中的作用。食品药品管理Johnsoniae PorSS除了在SprB的分泌中起作用外，还参与胞外几丁质酶的分泌。几丁质酶分泌不需要SprF，而PorSS分泌SprB可能需要SprF。在sprC或sprD中具有非极性突变的细胞产生并分泌SprB，并使其沿细胞表面快速沿着移动。多个旁系同源的sprB，sprC，sprD和sprF存在于基因组中，这可以解释为什么突变sprB，sprC，sprD和sprF不会导致运动性的完全丧失，并表明半冗余的SprB样粘附素可能允许细胞在不同表面上运动。
Cells of Flavobacterium johnsoniae move rapidly over surfaces by a process known as gliding motility. Gld proteins are thought to comprise the gliding motor that propels cell surface adhesins, such as the 669-kDa SprB. A novel protein secretion apparatus called the Por secretion system (PorSS) is required for assembly of SprB on the cell surface. Genetic and molecular analyses revealed that sprB is part of a seven-gene operon spanning 29.3 kbp of DNA. In addition to sprB, three other genes of this operon (sprC, sprD, and sprF) are involved in gliding. Mutations in sprB, sprC, sprD, and sprF resulted in cells that failed to form spreading colonies on agar but that exhibited some motility on glass in wet mounts. SprF exhibits some similarity to Porphyromonas gingivalis PorP, which is required for secretion of gingipain protease virulence factors via the P. gingivalis PorSS. F. johnsoniae sprF mutants produced SprB protein but were defective in localization of SprB to the cell surface, suggesting a role for SprF in secretion of SprB. The F. johnsoniae PorSS is involved in secretion of extracellular chitinase in addition to its role in secretion of SprB. SprF was not needed for chitinase secretion and may be specifically required for SprB secretion by the PorSS. Cells with nonpolar mutations in sprC or sprD produced and secreted SprB and propelled it rapidly along the cell surface. Multiple paralogs of sprB, sprC, sprD, and sprF are present in the genome, which may explain why mutations in sprB, sprC, sprD, and sprF do not result in complete loss of motility and suggests the possibility that semiredundant SprB-like adhesins may allow movement of cells over different surfaces.