Current Projects
Project 1: Factors influencing the migration of neural crest cells along the gut.
The migration of enteric neural crest cells is known to be mediated by multiple factors, including cell adhesion molecules (such as L1) and guidance molecules (such as members of the semaphorin family). In this project, you will examine the role of known guidance molecules in the migration of enteric neural crest cells within the developing gut, using a variety of in vitro and in vivo assays (such as catenary cultures, attraction and/or repulsion assays and time-lapse microscopy).
Selected frames of an E12.5 gut showing the migration of GFP+ enteric neural crest cells using time-lapse microscopy. Time is noted in minutes (’).
Project 2: Factors influencing the migration of neural crest cells within the caecum.
We have recently shown that when neural crest cells reach the caecum, their migratory properties are altered such that they are no longer able to migrate within the midgut. This suggests that the caecum possess molecules that may alter neural crest migration. In this project, you will identify molecules that are expressed within the caecum (using microarrays and in situ hybridisation) and then examine whether these molecules alter cell migration (using a variety of in vitro assays).
Comparison of distance that pre-caecal and caecal cells migrate in recipient pre-caecal and post-caecal gut. The most distal cell is indicated with an arrow. Pre-caecal cells colonised both pre-caecal and post-caecal recipient gut equally well (top panel). Caecal cells colonised pre-caecal recipient explants poorly, but migrated a similar distance along post-caecal recipients to pre-caecal cells (bottom panel).
Project 3: Role of L1CAM as a modifier gene in Hirschsprung’s disease.
L1CAM is an X-linked gene that encodes the cell adhesion molecule, L1. In humans, mutations in L1CAM have been implicated in a range of neurological disorders. Some individuals with L1CAM mutations also have Hirschsprung’s disease, suggesting a possible role for this gene in ENS development. We have recently shown that: (i) L1 is expressed by enteric neural crest cells as they migrate through the developing mouse gut; (ii) disrupting L1 activity retards enteric neural crest cell migration in explants of embryonic mouse gut in vitro; and (iii) L1CAM null mutant mice show a significant delay in enteric neural crest cell migration. However, the entire gastrointestinal tract is fully colonised prior to birth. This suggests that L1CAM may function as an X-linked modifier gene. A modifier gene is defined as a gene that when mutated, is insufficient on its own to produce an effect. However, when coupled with another genetic mutation, it produces or enhances an effect. In this project, you will examine whether genetic interactions between L1CAM and other known Hirschsprung susceptibility genes results in a Hirschsprung-like phenotype. To do this you will use a variety of methods, including genetic and molecular analysis, microdissection, histochemistry and confocal microscopy.