Chiral morphogenesis and cilia patterning
Chirality plays an important role in left-right symmetry breaking during morphogenesis. Moreover, preliminary data suggests that many marine embryos rotate in with the same chirality, hinting at possible evolutionary conserved mechanism in how cilia is being patterned. Related work in other organisms show that cilia patterning is partly specified by planar cell polarity pathway (PCP), which in turn is controlled by upstream Wnt developmental pathway. But how chirality symmetry is broken remains unknown. In our lab, we aim to use sea star embryo as a model to address this question. In particular, we are focusing on morphogenetic events during the blastula stage to look for mechanical signatures of chiral symmetry breaking.
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Moreover, sea star embryo which undergoes complex morphological changes during early development also exhibit intricate evolution in their cilia-driven hydrodynamic flow field, making it an attractive model to study collective behavior of ciliary arrays and bands under a wide range of geometrical and topological constraints. The lab is interested in two general directions:
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Structurally, how is the orientation of cilia beating plane arranged? Ciliary beating plane is often regulated by planar cell polarity (PCP) pathway, which is in turn controlled by upstream morphogen. Here, we will investigate how developmental signaling regulates PCP and determines the cilia orientation field at the different stages of sea star embryogenesis.
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Dynamically, how do cilia beating patterns coordinate? It is well known that hydrodynamical coupling between cilia gives rise to metachronal waves on flat 2D surfaces. However, ciliary arrays on sea star embryos are spread over curved surfaces in different configurations. Here, we will determine the cilia beating shape (in-plane vs rotary), how ciliary beating is synchronized on surfaces of different curvatures, and whether defects in the beating phase arise.
