Abstract
Polarity is a shared feature of most cells. In epithelia, apical-basal polarity often coexists, and sometimes intersects with planar cell polarity (PCP), which orients cells in the epithelial plane. From a limited set of core building blocks (e.g. the Par complexes for apical-basal polarity and the Frizzled/Dishevelled complex for PCP), a diverse array of polarized cells and tissues are generated. This suggests the existence of little-studied tissue-specific factors that rewire the core polarity modules to the appropriate conformation. In Drosophila sensory organ precursors (SOPs), the core PCP components initiate the planar polarization of apical-basal determinants, ensuring asymmetric division into daughter cells of different fates. We show that Meru, a RASSF9/RASSF10 homologue, is expressed specifically in SOPs, recruited to the posterior cortex by Frizzled/Dishevelled, and in turn polarizes the apical-basal polarity factor Bazooka (Par3). Thus, Meru belongs to a class of proteins that act cell/tissue-specifically to remodel the core polarity machinery.
Highlights
Polarity is a fundamental feature of most cells and tissues
In third instar wing imaginal discs, Meru was only detected in sensory organ precursors (SOPs) cells (Figure 1A–B’ and Figure 1—figure supplement 1F–F’’), which can be identified by the expression of Hindsight (Hnt) (Figure 1—figure supplement 1F–F’’), a marker for specified SOP cells (Koelzer and Klein, 2003)
This is consistent with previous reports indicating that meru mRNA is highly expressed in SOPs, as it is a transcriptional target of the proneural transcription factors of the Achaete-Scute complex (AS-C) (Reeves and Posakony, 2005; Buffin and Gho, 2010)
Summary
Polarity is a fundamental feature of most cells and tissues. It is evident both at the level of individual cells (e.g. apical-basal polarity in epithelia, budding in Saccharomyces cerevisiae [St Johnston and Ahringer, 2010, Martin and Arkowitz, 2014]) and groups of cells (e.g. planar cell polarity (PCP) in epithelia [Singh and Mlodzik, 2012; Devenport, 2014]). Despite the fact that different cell types use a common set of molecules to establish and maintain polarity (Par complexes, Fz-PCP pathway), the organization of polarized cells and cell assemblies varies dramatically across different species and tissues (Bryant and Mostov, 2008). This implies the existence of factors that act in a cell or tissue-specific manner to modulate/rewire the core polarity machinery into the appropriate organization.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
