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Ultrastructural, tomographic and confocal imaging of the chondrocyte primary cilium in situ
Author(s) -
Jensen C.G.,
Poole C.A.,
McGlashan S.R.,
Marko M.,
Issa Z.I.,
Vujcich K.V.,
Bowser S.S.
Publication year - 2004
Publication title -
cell biology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 77
eISSN - 1095-8355
pISSN - 1065-6995
DOI - 10.1016/j.cellbi.2003.11.007
Subject(s) - cilium , axoneme , chondrocyte , ultrastructure , extracellular matrix , microbiology and biotechnology , cartilage , electron tomography , anatomy , biophysics , confocal , chemistry , biology , electron microscope , optics , biochemistry , physics , flagellum , scanning transmission electron microscopy , gene
Abstract Hyaline cartilage chondrocytes express one primary cilium per cell, but its function remains unknown. We examined the ultrastructure of chick embryo sternal chondrocyte cilia and their interaction with extracellular matrix molecules by transmission electron microscopy (TEM) and, for the first time, double‐tilt electron tomography. Ciliary bending was also examined by confocal immunohistochemistry. Tomography and TEM showed the ciliary axoneme to interdigitate amongst collagen fibres and condensed proteoglycans. TEM also revealed the presence of electron‐opaque particles in the proximal axoneme which may represent intraciliary‐transport (ICT) particles. We observed a wide range of ciliary bending patterns. Some conformed to a heavy elastica model associated with shear stress. Others were acutely deformed, suggesting ciliary deflection by collagen fibres and proteoglycans with which the cilia make contact. We conclude that mechanical forces transmitted through these matrix macromolecules bend the primary cilium, identifying it as a potential mechanosensor involved in skeletal patterning and growth.