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Procentriole assembly revealed by cryo‐electron tomography
Author(s) -
Guichard Paul,
Chrétien Denis,
Marco Sergio,
Tassin AnneMarie
Publication year - 2010
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/emboj.2010.45
Subject(s) - centrosome , centriole , biology , microtubule , microbiology and biotechnology , cryo electron tomography , microtubule nucleation , basal body , organelle , flagellum , cell cycle , cell , genetics , physics , gene , optics , tomography
Centrosomes are cellular organelles that have a major role in the spatial organisation of the microtubule network. The centrosome is comprised of two centrioles that duplicate only once during the cell cycle, generating a procentriole from each mature centriole. Despite the essential roles of centrosomes, the detailed structural mechanisms involved in centriole duplication remain largely unknown. Here, we describe human procentriole assembly using cryo‐electron tomography. In centrosomes, isolated from human lymphoblasts, we observed that each one of the nine microtubule triplets grows independently around a periodic central structure. The proximal end of the A‐microtubule is capped by a conical structure and the B‐ and C‐microtubules elongate bidirectionally from its wall. These observations suggest that the gamma tubulin ring complex (γ‐TuRC) has a fundamental role in procentriole formation by nucleating the A‐microtubule that acts as a template for B‐microtubule elongation that, in turn, supports C‐microtubule growth. This study provides new insights into the initial structural events involved in procentriole assembly and establishes the basis for determining the molecular mechanisms of centriole duplication on the nanometric scale.