Meeting Abstract

66.1  Tuesday, Jan. 6  Notch signaling during embryogenesis in the cnidarian Nematostella vectensis MARLOW, H. Q.; ROETTINGER, E.; MARTINDALE, M.Q.*; Univ. Hawaii, Kewalo Marine Lab mqmartin@hawaii.edu

Nematostella vectensis, the startlet sea anemone, is an anthozoan cnidarian and early branching member of the metazoa. As a morphologically simple early metazoan it possesses only two tissue layers (endoderm and ectoderm) and a nerve net and is ideal for investigating the role of many developmental pathways in the evolution of conserved features such as the nervous system and gut. The notch pathway has been implicated in a number of developmental processes including segmentation, neurogenesis and gastrulation. The notch receptor, delta ligand and a number of downstream targets including the basic helix-loop-helix genes are present in the N. vectensis genome and are shown to be expressed prior to gastrulation and throughout the planula (larval) stage by in situ hybridization studies. Inhibition of notch signaling the by the gamma-secretase inhibitor DAPT induces marked morphological defects in global processes such as cell proliferation as well as cell-type specific abnormalities (absence of cnidocyte stinging cells). Diverse roles of this pathway in N. vectensis development is consistent with its many roles in bilaterian animals. We are currently functionally testing the role of specific pathway members in N. vectensis through the expression of dominant negative forms of the ligand delta and the transcription factor suppressor of hairless in early embryos. Determining the role of Notch signaling in early metazoans such as N. vectensis provides insight into the ancestral role of this pathway and additional data for its more general role in cell proliferation.