The specialized secretory apparatus ESX-1 is essential for DNA transfer in Mycobacterium smegmatis
The specialized secretory apparatus ESX-1 is essential for DNA transfer in Mycobacterium smegmatis
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DOI：
10.1111/j.1365-2958.2008.06299.x
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发表时间：
2008-08-01
影响因子：
3.6
通讯作者：
Derbyshire, Keith M.
中科院分区：
文献类型：
--
作者：
Coros, Abbie;Callahan, Brian;Derbyshire, Keith M.
耻垢分枝杆菌中的接合DNA转移通过与质粒介导的DNA转移不同的机制发生。以前，我们已经表明，分泌装置，ESX-1，负调控DNA转移从供体菌株; ESX-1供体突变体是超接合。在这里，我们描述了一个全基因组转座子诱变筛选分离受体突变体。令人惊讶的是，我们发现，大多数插入地图内的esx-1基因座，它编码的分泌器。因此，与其在供体功能中的作用相反，ESX-1对于受体功能是必需的;受体ESX-1突变体是低接合的。除了esx-1基因，我们的筛选确定了新的非esx-1基因座在M。DNA转移和ESX-1活性所需的smeglycoprotein基因组。因此，DNA转移提供了一种简单的分子遗传学测定来表征ESX-1，其在结核分枝杆菌中是完全毒力所必需的。这些发现加强了DNA转移和ESX-1分泌的功能性交织，这在M。包皮环切术供体。此外，我们观察到ESX-1对供体和受体的转移具有如此截然相反的作用，这迫使我们考虑ESX-1装置分泌的蛋白质如何发挥作用以调节两个看似不同的过程，M.耻垢病DNA转移和M.结核病毒力
Conjugal DNA transfer in Mycobacterium smegmatis occurs by a mechanism distinct from plasmidmediated DNA transfer. Previously, we had shown that the secretory apparatus, ESX-1, negatively regulated DNA transfer from the donor strain; ESX-1 donor mutants are hyper-conjugative. Here, we describe a genome-wide transposon mutagenesis screen to isolate recipient mutants. Surprisingly, we find that a majority of insertions map within the esx-1 locus, which encodes the secretory apparatus. Thus, in contrast to its role in donor function, ESX-1 Is essential for recipient function; recipient ESX-1 mutants are hypo-conjugative. In addition to esx-1 genes, our screen identifies novel non-esx-1 loci in the M. smegmatis genome that are required for both DNA transfer and ESX-1 activity. DNA transfer therefore provides a simple molecular genetic assay to characterize ESX-1, which, in Mycobacterium tuberculosis, is necessary for full virulence. These findings reinforce the functional intertwining of DNA transfer and ESX-1 secretion, first described in the M. smegmatis donor. Moreover, our observation that ESX-1 has such diametrically opposed effects on transfer in the donor and recipient, forces us to consider how proteins secreted by the ESX-1 apparatus can function so as to modulate two seemingly disparate processes, M. smegmatis DNA transfer and M. tuberculosis virulence.