Grants We Funded

Abstract
The 1rf6 gene has been cloned in zebrafish and preliminary expression analysis has been described. We plan to carry out a detailed time-course expression analysis of 1rf6, in the context of other genes involved in vertebrate pharyngeal arch development (such as sonic hedgehog, wnt9b, dlx2, dHand, runx2, Msxl, endothelin-l) using whole mount RNA in situ hybridization. We will also analyze 1116 expression in existing zebrafish pharyngeal arch mutations (such as sucker/endothelin-l) in order to place 1rf6 in a genetic pathway. We hypothesize that 1rf6 has expression pattern overlaps with subsets of cranial neural crest progenitors that express genes involved in neural crest induction and specification (such as dlx2 and MsxI) but is activated later during pharyngeal morphogenesis. We anticipate that 1rf6 expression will be perturbed by zebrafish mutations in genes regulating jaw formation. We will exploit the ability to carry out rapid gene knockdown in zebrafish in order to assess the functional requirement for 1rf6 during zebrafish embryogenesis. We will examine the morphological effects of 1rf6 deficiency by Alcian blue staining of the head cartilages and investigate molecular defects by surveying known markers of the developing jaw (such as dlx-2, and msx genes). From this analysis we should be able to compare the zebrafish craniofacial phenotype caused by 1rf6 deficiency to the known mouse gene-targeting and human mutation phenotypes. Complementary gene disruption approaches are also planned, such as expression of dominant negative 1rf6 mutant proteins by mRNA microinjection and stable transgenics. We hypothesize that 1rf6 is required for proper differentiation of first pharyngeal derivatives. Inactivation of 1rf6 may create a defect in that palatquadrate, a teleost jaw structure analogous to mammalian maxilla. There may also be epidermal differentiation defect, as 1rf6 has been implicated to regulate epithelial-mesenchymal transition in the mouse model.

Biography
Eric C. Liao, M.D., Ph.D. is an Assistant in Surgery at Massachusetts General Hospital and the Boston Shriners Hospital for Children. His clinical interests are in microsurgery reconstruction and pediatric plastic surgery. Dr. Liao is the principal investigator of the craniofacial laboratory with research focused on cleft lip and palate malformation utilizing innovative genetic approaches. His work is funded by several prestigious awards, including the American Surgical Association Research Fellowship, the Basil O’Connor Start Scholar Award from the March of Dimes, and current and past awards from the Plastic Surgery Education Foundation.