Control of tissue integrity in the C. elegans seam-cell epithelium


Supervising PI

Mike Boxem (website)

Project Description

Background

Epithelial tumours are characterized by loss of cell polarity, and an epithelial to mesenchymal transition (EMT). To date, it is still not clear if and to what extent loss of polarity is a causative early step in the development of cancer. In this project we will examine the mechanisms that maintain tissue integrity in the seam cell epithelium. The C. elegans seam cells form a polarized epithelium that undergoes a series of asymmetric, stem cell-like divisions in anterior-posterior direction, where the smaller anterior daughter fuses with the hypodermis while the larger posterior daughter retains the seam cell fate. Research by our collaborators (Van den Heuvel) and others demonstrated that the axis of division is redundantly controlled by the Wnt signalling pathway and cell shape. Although aberrant division axes cause additional seam cells to form outside of the normal linear row of cells, these cells never detach from the epithelium.

Objectives

Our goal is to drive the seam cells toward a tumorous phenotype, where individual cells leave the epithelium, by combining mutations that disrupt the axis of division with disruption of apical-basal polarity and cell adhesion. These experiments are uniquely possible by use of tissue-specific gene inactivation developed by the Van den Heuvel group, so that effects can be investigated at individual cell level in the context of an otherwise healthy organism.

Methodology

  • CRISPR/Cas9-mediated genome engineering to generate deletion alleles, specific point mutants, and endogenously tagged fluorescent proteins.
  • Genetic screens.
  • RNA-mediated inactivation.
  • Tissue-specific protein inactivation using Cre-lox recombination (with the Van den Heuvel group) or ZIF-1 mediated degradation.
  • Automated analysis of seam cells using a Union Biometrica BioSorter

Collaborators

Key publications

  1. Waaijers S, Ramalho JJ, Koorman T, Kruse E, Boxem M. The elegans Crumbs family contains a CRB3 homolog and is not essential for viability. Biol Open. 2015;4(3):276–84.
  2. Waaijers S, Boxem M. Engineering the Caenorhabditis elegans genome with CRISPR/Cas9. 2014 Mar 28;68(3):381–8.
  3. Waaijers S, Koorman T, Kerver J, Boxem M. Identification of human protein interaction domains using an ORFeome-based yeast two-hybrid fragment library. J Proteome Res. 2013 Jul 5;12(7):3181–92.
  4. Boxem M, Maliga Z, Klitgord N, Li N, Lemmens I, Mana M, et al. A protein domain-based interactome network for elegans early embryogenesis. Cell. 2008 Aug 8;134(3):534–45.