Event
Bioengineering Seminar Series: Lisa Taneyhill
Wednesday, April 30, 2008
2:00 p.m.-3:00 p.m.
0408 Animal Science/Agriculture Engineering Bldg.
Professor Helim Aranda-Espinoza
(301) 405-8250
helim@umd.edu
Neural Crest Cell Migration in the Chick Embryo
Presented by Lisa Taneyhill
Animal and Avian Sciences
University of Maryland
Neural crest cells are a transient population of migratory cells that arise during neurulation at the border of the neural and non-neural ectoderm in the developing vertebrate embryo. Initially existing as adherent, epithelial cells in the dorsal neural tube (premigratory neural crest), these cells undergo an epithelial-to-mesenchymal transition (EMT) to generate motile neural crest cells that migrate away and subsequently differentiate into various structures, including the craniofacial skeleton and peripheral nervous system. The Snail family of transcriptional repressors is known to play key roles during EMTs underlying both normal embryonic development and disease. In the avian embryo, Snail2 functions to repress gene expression in premigratory neural crest cells to facilitate EMT and neural crest cell emigration. The cell adhesion molecule cadherin6B (Cad6B) is a direct target of Snail2 repression during neural crest EMT. Prior to neural crest EMT, premigratory neural crest cells express Cad6B. During EMT, Snail2 binds to E boxes in the Cad6B regulatory region and directly represses Cad6B transcription, thus allowing cells to initiate emigration from the neural tube through the loss of cell-cell adhesion. Furthermore, Cad6B functions as an important temporal regulator of neural crest EMT and migration in the avian embryo. Knock-down of Cad6B in the dorsal neural tube leads to premature neural crest cell emigration in vivo and in vitro. Conversely, overexpression of Cad6B abrogates neural crest cell emigration in vivo. Current experiments in the Taneyhill lab include (1) the functional characterization of Wnt target genes during neural crest development; (2) the identification and functional characterization of Snail2 target genes during neural crest emigration; and (3) the molecular mechanism by which Cad6B expression is regulated during neural crest EMT, both at the RNA and protein levels. The overall goal of the lab is to delineate the molecular basis of avian neural crest development by examining mechanisms controlling the induction, migration, and differentiation of the neural crest.
