Genetic and molecular analysis of lawd-1, an essential gene in epithelial development and morphogenesis

Abstract

Epithelial cells are capable of undergoing dynamic rearrangements to form sheets and tubes during morphogenesis. These dynamic changes are controlled by a network of proteins responsible for inducing and maintaining polarity, cell junctions and cytoskeletal associations. In this study, I analysed the function of a novel C. elegans gene named lawd-1 (lumen associated with WD40 domain). Genetic analyses revealed that lawd-1 mutants exhibit variable morphogenetic defects throughout development. The first allele was identified because of the appearance of a Notched-head. Later characterisation of a lawd-1 null allele confirmed that lawd-1 has essential roles in development. Co-expression studies using fluorescent proteins as intracellular markers and a mCherry tagged LAWD-1 revealed the dynamic pattern of LAWD-1 expression. LAWD-1 was shown to be enriched along the apical membrane of epithelial tissues beginning in the late embryo. LAWD-1 continues to be expressed at post-embryonic stages of development. Evidence is presented showing that LAWD-1 is associated with the actomyosin contractility network. LAWD-1 encodes multiple protein isoforms; the largest isoforms carry the protein-protein interaction WD40 domain. A screen to identify potential LAWD-1 interacting proteins was carried out by performing co-immunoprecipitation followed by mass spectroscopy. Characterisation of one of the proteins identified by this screen, VAB-10B, a spectraplakin cytoskeleton linker is presented. A model is presented speculating that LAWD-1 functions in controlling cytoskeletal dynamics through its interaction with VAB-10B.

Date of Award	8 May 2018
Original language	English
Awarding Institution	University of Bristol
Supervisor	Patricia E Kuwabara (Supervisor) & Ian R Collinson (Supervisor)