The Hedgehog (Hh)/Patched (Ptc) signalling pathway promotes cell proliferation and plays a central role in establishing embryonic polarity and organ patterning in Drosophila and vertebrates. In humans, dysregulation this pathway can cause cancer and developmental abnormalities. C. elegans encodes a large number of Ptc and Hh-related proteins, but it remains unclear whether these proteins participate in cell-cell signalling (1,2). We previously showed that
ptc-1 is essential for germ line cytokinesis (3). To determine whether PTC proteins play more global roles in somatic cytokinesis, we performed an RNAi screen. To this end, we identified the
ptr-2 (ptc-related) gene.
ptr-2(RNAi) embryos arrest with multinucleated cells, which we attribute to a defec t in cytokinesis (1). Given the multitude of ptc and ptr genes in the worm, we obtained a
ptr-2 mutant to show that the disruption of cytokinesis by
ptr-2(RNAi) is not due to off target effects. We find that
ptr-2 mutants do not display a phenotype identical to that of
ptr-2(RNAi) animals; however, cytokinesis defects are indeed present in the progeny of
ptr-2 (m- z+) mothers. Time-lapse recordings of
ptr-2(RNAi) embryos reveal defects in chromosome condensation/segregation, spindle positioning and cleavage furrow formation. We have generated PTR-2 antibodies and have examined the intracellular localisation of PTR-2. To gain a better understanding of PTR-2 dynamics, we have generated a
pie-1::
ptr-2::mRFP reporter, which is capable of rescuing a
ptr-2 mutant. We will show that PTR-2 is dynamically distributed in vesicles throughout the cell-cycle and discuss the role of the cytoskeleton in PTR-2 localisation. 1. Zugasti et al., 2005 2. Burglin and Kuwabara, 2006 3. Kuwabar a et al., 2000