Cilia
Multiciliated cell
Cilia have diverse functions at the interface between the cell and the extracellular space.
Cilia are large complex organelles composed of the ciliary axoneme surrounded by the ciliary membrane. The axoneme is comprised of 9 microtubule doublets and attached motor and transport proteins. Many cells have a single cilium that arises from the centriole (a monocilium). By displaying a variety of receptors, these “signaling” cilia are adapted to function as “cellular antennae”, reaching out beyond the cell surface to capture a variety of signals. Monocilia are created and resorbed in a cell-cycle dependent manner, predicting a central role in cell cycle regulation. Mechanisms that contribute to the biogenesis and resorption of cilia remain ill defined.
Monocilium
In motile cilia, such as on the multiciliated epidermis (trachea, oviduct, or Xenopus tadpole skin), dynein motors generate ciliary movement, which drives fluid flow. In the Left-Right Organizer (LRO), this fluid flow is the initiating event in the LR signaling cascade, and is essential for proper cardiac looping and heart development. Defects in the structure and function of cilia are the cause of many diseases, collectively referred to as the ciliopathies. These include heterotaxy, but can also lead to blindness, deafness, pulmonary infections, infertility, and kidney disorders as well as others. In our analysis of patients with congenital malformations, we have identified a number of genes that affect cilia. Some of them act directly on the cilium, while others act indirectly to change cilia types or downstream signaling.
Cilia Video Gallery
GRP cilia
Ciliary movement in Xenopus GRP (node) creates leftward fluid flow, initiating molecular cascade to break left-right symmetry.
Bead flow assay
Bead flow over embryo indicates epidermal ciliary function - Choma Lab
Cilia IFT
membrane-RFP and IFT80-GFP, Xenopus epidermal cilia.
UIC epidermis beating_396
Epidermal cilia beating normally in Xenopus embryo
Ciliary IFT in WT embryo
intraflagellar transport - anterograde and retrograde movement in Xenopus cilia
WT-epidermal cilia (mem-GFP)
normal movement of Xenopus epidermal cilia (marked with membrane GFP)