Construction and characterization of a Mycobacterium tuberculosis mutant lacking the alternate sigma factor gene, sigF
Construction and characterization of a Mycobacterium tuberculosis mutant lacking the alternate sigma factor gene, sigF
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DOI：
10.1128/iai.68.10.5575-5580.2000
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发表时间：
2000-10-01
影响因子：
3.1
通讯作者：
Bishai, WR
中科院分区：
文献类型：
--
作者：
Chen, P;Ruiz, RE;Bishai, WR
替代RNA聚合酶sigma因子基因sigF在稳定期和体外应激条件下表达，在结核分枝杆菌的有毒CDC1551菌株中已被删除。 Delta sigF突变体的生长速率与指数期的同基因野生型菌株相同，尽管在稳定期突变体达到了比野生型更高的密度。该突变体表现出对利福平和利福喷丁的敏感性增加。此外，Delta sigF 突变体表现出鹅去氧胆酸的摄取减少，并且通过与野生型 sigF 基因互补来逆转这种效应。未观察到人类单核细胞内突变型和野生型生物体的短期细胞内生长存在差异。同样，这些生物体对淋巴细胞介导的细胞内生长抑制的敏感性没有差异，然而，感染 Delta sigF 突变体的小鼠的平均死亡时间为 246 天，而野生型菌株感染的动物为 161 天（P < 0,001）。这些数据表明，结核分枝杆菌 sigF 在无菌培养中和在无菌培养中都是非必需的替代 sigma 因子。体外巨噬细胞。虽然 Delta sigF 突变体对小鼠产生致命的感染，但根据死亡时间分析，它的毒性低于野生型对应物。
The alternate RNA polymerase sigma factor gene, sigF, which is expressed in stationary phase and under stress conditions in vitro, has been deleted in the virulent CDC1551 strain of Mycobacterium tuberculosis. The growth rate of the Delta sigF mutant was identical to that of the isogenic wild-type strain in exponential phase, although in stationary phase the mutant achieved a higher density than the wild type. The mutant showed increased susceptibility to rifampin and rifapentine, Additionally, the Delta sigF mutant displayed diminished uptake of chenodeoxycholate, and this effect was reversed by complementation with a wild-type sigF gene. No differences in short-term intracellular growth between mutant and wild-type organisms within human monocytes were observed. Similarly, the organisms did not differ in their susceptibilities to lymphocyte-mediated inhibition of intracellular growth, However, mice infected with the Delta sigF mutant showed a median time to death of 246 days compared with 161 days for wild-type strain-infected animals (P < 0,001), These data indicate that M. tuberculosis sigF is a nonessential alternate sigma factor both in axenic culture and for survival in macrophages in vitro. While the Delta sigF mutant produces a lethal infection of mice, it is less virulent than its wild-type counterpart by time-to-death analysis.