Collaborative Proposal: Cellular and Molecular Dissection of "Organizing Activity" during Development in the Spiralia

点击翻译按钮获取中文摘要

During normal development, signals between cells in the early embryo can havesubstantial influence on how the body develops, such as how the eyes and brainbecome localized in the head or how the spinal cord becomes localized on the back andnot the belly. These early events have a tremendous effect on the organization of thetissues within the body and are critical for normal development of all animals. Thisproject will determine how changes in early developmental mechanisms can lead toformation of new body parts. The three study animals are segmented worms, and offerthe advantage that their embryos possess only 16 to 64 cells when these critical earlysignaling events occur. This contrasts with the approximately 1000 cells at a comparablestage in the vertebrate embryo. Thus, development will be studied on the single cell level,and similar cells can be compared across distantly related animals. The specific goals ofthis study are to identify the signaling cell and the molecules responsible for instructingsurrounding cells to correctly position and generate body parts. The proposed study willprovide strong STEM training opportunities by integrating scientific training with researchfor college students, graduate students and postdoctoral scholars. In addition, there willbe ongoing community outreach activities, including hands-on activities with severaldifferent K-12 age groups in the local school districts to teach about animal biodiversityof the oceans, and general talks to adults in the local community.This project seeks to understand how developmental changes lead to a range of bodyplans, and represents a unique opportunity to gain insight into the evolution ofdevelopmental programs. A group of animals known as the Spiralia exhibit enormousbody plan diversity, yet many phyla in this clade share a highly stereotypic embryologicalprogram called spiralian development. This conservation allows studies of the evolutionof homologous embryonic cell lineages with single cell resolution across diverse taxa.Specifically, the molecular signaling repertoire of a single cell will be determined, and theevolutionary plasticity of its organizing activity will be assessed by comparing distantlyrelated species. Spiralian development will be investigated experimentally in theannelids Capitella teleta, Platynereis dumerilii and Chaetopterus sp. The phylogeneticposition and embryonic studies of the three species will be used to reconstruct theancestral cellular and molecular characteristics of annelid organizing activity. Specificgoals of the project utilizing the three annelids are: 1) deletion of single cells in earlystage embryos to identify cell(s) possessing 'organizing activity', 2) identification ofmolecular signals that mediate organizing activity, 3) determination of the function oforganizing signals by knockdown and mis-expression studies. The proposed study willprovide strong training opportunities by integrating scientific training with research, andcontinue to develop Capitella and Platynereis as annelid models for Evo-Devo studies.There will be ongoing community outreach activities, including hands-on activities withseveral different age groups in the local school districts that highlight biodiversity in theoceans, and general talks to adult audiences in the local community.