title: The C. elegans Crumbs family contains a CRB3 homolog and is not essential for viability.
abstract: Crumbs proteins are important regulators of epithelial polarity. In C. elegans, no essential role for the two described Crumbs homologs has been uncovered. Here, we identify and characterize an additional Crumbs family member in C. elegans, which we termed CRB-3 based on its similarity in size and sequence to mammalian CRB3. We visualized CRB-3 subcellular localization by expressing a translational GFP fusion. CRB-3::GFP was expressed in several polarized tissues in the embryo and larval stages, and showed apical localization in the intestine and pharynx. To identify the function of the Crumbs family in C. elegans development, we generated a triple Crumbs deletion mutant by sequentially removing the entire coding sequence for each crumbs homolog using a CRISPR/Cas9-based approach. Remarkably, animals lacking all three Crumbs homologs are viable and show normal epithelial polarity. Thus, the three C. elegans Crumbs family members do not appear to play an essential role in epithelial polarity establishment.
authors: Division of Developmental Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
authors: Selma
authors: S
authors: Waaijers
authors: Division of Developmental Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
authors: João Jacob
authors: JJ
authors: Ramalho
authors: Division of Developmental Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
authors: Thijs
authors: T
authors: Koorman
authors: Division of Developmental Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
authors: Elisabeth
authors: E
authors: Kruse
authors: Division of Developmental Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands. m.boxem@uu.nl.
authors: Mike
authors: M
authors: Boxem
keywords: C. elegans; CRB; Crumbs; cell polarity