Problems associated with the development of the ear can result in vertigo and partial or complete hearing loss. Efforts to better understand the development of the inner ear have been made in mouse, frog, chick, and other species. However, there is still relatively little known about the mechanisms that control the processes during development. This research has used the African Clawed Frog, Xenopus laevis, to study embryonic and inner ear development. The gene Wnt3a was previously determined to be expressed in the dorsal half of the developing otocyst. This suggested a possible role for Wnt3a in inner ear development, but little has been done to determine the specific purpose of Wnt3a. To examine the role of Wnt3a in the development of the inner ear we wanted to inject Wnt3a and antagonists to affect inner ear development without disturbing the formation of the dorsoventral axis. Therefore we developed an animal cap assay to alleviate this problem. We extracted animal caps at late blastula and soaked them in noggin protein to induce the formation of the head. Our results showed that noggin protein is capable of rescuing animal cap cells. An in situ hybridization with a probe for Wnt3a was used to determine if the ears produced via this method expressed the gene of interest. No results were obtained from the in situ. In the future it will be necessary to repeat the hybridization. Our hypothesis is that injection of antagonists and activators of Wnt will affect the formation of the inner ear, supporting Wnt3a's role in its development. From this further work could determine what genes lie upstream and downstream of Wnt3a, which would provide a more accurate picture of inner ear development, therefore opening more avenues of treatment for hearing impaired individuals.
Hodges, H. E. (2006). Affecting Wnt3a in the Inner Ear of Xenopus laevis (Undergraduate honors thesis, University of Redlands). Retrieved from http://inspire.redlands.edu/cas_honors/134