Molecular specification of the pre-placodal ectoderm

George Washington University, Washington DC

Investigators

Abstract

Sally A. Moody, Ph.D. Proposal# IOS-0817902 "Molecular specification of the pre-placodal ectoderm." The "ectoderm" of the vertebrate embryo is initially patterned into four domains: epidermis (skin), neural plate (the precursor of the central nervous system), neural crest (a precursor of the peripheral nervous system) and pre-placodal ectoderm (the precursor of several sensory organs in the head). In particular, the pre-placodal ectoderm gives rise to the olfactory and auditory systems, the lens of the eye, numerous sensory neurons in the head and the lateral line organ in fish and amphibians. Although the developmental mechanisms that regulate the formation of the neural plate, neural crest and epidermis have been studied extensively, very little is known about the development of the pre-placodal ectoderm. This proposal will elucidate the molecular interactions that: 1) induce the formation of the pre-placodal ectoderm; and 2) establish and maintain the boundaries between the four ectodermal domains as the head develops. Although these early steps of placode development have been overlooked in mutant mouse studies, perhaps because they occur very early when rodent embryos are especially fragile, they are particularly amenable to study in Xenopus frogs because of easy access to the early developmental stages and wealth of available molecular and embryological tools. The proposed studies will provide important new knowledge about the genes and tissue interactions that establish this important ectodermal domain, and is expected to elucidate the genetic and evolutionary changes that have occurred in these structures across vertebrates. In terms of Broader Impacts, because the Xenopus system allows one to visualize and manipulate gene expression without extensive technical expertise, the experimental approaches can be taught to high school, undergraduate and graduate students and thereby provide an outstanding learning experience for students interested in exploring a career in science.