National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)
5R01AI152421-02
米国
引用
ジャーナル: Infect Immun / 年: 2022 タイトル: Developmental Transitions Coordinate Assembly of the Coxiella burnetii Dot/Icm Type IV Secretion System. 著者: Donghyun Park / Samuel Steiner / Meng Shao / Craig R Roy / Jun Liu / 要旨: Coxiella burnetii is an obligate intracellular bacterial pathogen that has evolved a unique biphasic developmental cycle. The infectious form of C. burnetii is the dormant small cell variant (SCV), ...Coxiella burnetii is an obligate intracellular bacterial pathogen that has evolved a unique biphasic developmental cycle. The infectious form of C. burnetii is the dormant small cell variant (SCV), which transitions to a metabolically active large cell variant (LCV) that replicates inside the lysosome-derived host vacuole. A Dot/Icm type IV secretion system (T4SS), which can deliver over 100 effector proteins to host cells, is essential for the biogenesis of the vacuole and intracellular replication. How the distinct C. burnetii life cycle impacts the assembly and function of the Dot/Icm T4SS has remained unknown. Here, we combine advanced cryo-focused ion beam (cryo-FIB) milling and cryo-electron tomography (cryo-ET) imaging to visualize all developmental transitions and the assembly of the Dot/Icm T4SS . Importantly, assembled Dot/Icm machines were not present in the infectious SCV. The appearance of the assembled Dot/Icm machine correlated with the transition of the SCV to the LCV intracellularly. Furthermore, temporal characterization of C. burnetii morphological changes revealed regions of the inner membrane that invaginate to form tightly packed stacks during the LCV-to-SCV transition at late stages of infection, which may enable the SCV-to-LCV transition that occurs upon infection of a new host cell. Overall, these data establish how C. burnetii developmental transitions control critical bacterial processes to promote intracellular replication and transmission.
集束イオンビーム - 装置: OTHER / 集束イオンビーム - イオン: OTHER / 集束イオンビーム - 電圧: 3 kV / 集束イオンビーム - 電流: 0.05 nA / 集束イオンビーム - 時間: 3600 sec. / 集束イオンビーム - 温度: 103 K / 集束イオンビーム - Initial thickness: 10000 nm / 集束イオンビーム - 最終 厚さ: 150 nm 集束イオンビーム - 詳細: The value given for _emd_sectioning_focused_ion_beam.instrument is FEI Aquilos. This is not in a list of allowed values {'OTHER', 'DB235'} so OTHER is written into the XML file.
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電子顕微鏡法
顕微鏡
FEI TITAN KRIOS
特殊光学系
位相板: VOLTA PHASE PLATE
撮影
フィルム・検出器のモデル: GATAN K3 (6k x 4k) / 平均電子線量: 1.7 e/Å2
電子線
加速電圧: 300 kV / 電子線源: FIELD EMISSION GUN
電子光学系
照射モード: OTHER / 撮影モード: OTHER / 最大 デフォーカス(公称値): 0.5 µm / 最小 デフォーカス(公称値): 0.5 µm