Gregory Ellis
gellis@morel.uoregon.edu

University of Oregon
Institute of Molecular Biology
1210 University of Oregon
Eugene, OR 97403-1210 USA

Advisors:
Dr. Bruce Bowerman, Institute of Molecular Biology
Dr. Michael Lynch, Indiana University

IGERT Trainee from 1999-2002

________________________

Research Interests

Greg is currently a postdoc at the Cancer Research Institute at UCSF

 ***

During early embryogenesis, organisms utilize a variety of mechanisms to insure proper segregation of developmental determinants (ie RNAs, proteins, etc.) which in turn are required for many aspects of development such as embryonic polarity and fate specification. In many animal species, including humans, the first mitotic cleavage yields a two-blastomere stage embryo in which both cells are equal with respect to size, cell-cycle timing, and embryonic potential. Therefore, a separation of these two cells can give rise to two separate organisms. However, in C. elegans, the first mitotic cleavage of the one cell zygote, called P0, is asymmetric, producing two daughter blastomeres that are unequal in size with differential determinants, subsequently giving these two cells unique developmental potential. Because mutations that occur earlier in development are directly proportional to a more drastic phenotypic effect, these mutations are almost always deleterious. Therefore, the mechanisms that specify embryogenesis must have been established early in metazoan evolution. In the Bowerman lab, I am taking a genetic approach through the isolation and characterization of alleles of genes required for proper spindle orientation. A common spindle defective of these mutations is a transverse P0 spindle, which is normally longitudinal in wildtype animals. Correct mitotic spindle orientation is required so that the first cytokinesis yields two asymmetic blastomeres with proper segregation of different developmental determinants. Thus, understanding which genes control the earliest developmental processes should give a better understanding of how evolution first established differential mechanisms of species specification.

________________________

Publications

Shelton CA, Carter JC, Ellis GC, and Bowerman B. (1999) The nonmuscle myosin regulatory light chain gene mlc-4 is required for cytofinesis, anterior-posterior polarity, and body morphology during Caenorhabditis elegans embryogenesis. J. Cell Biol. 146:2. 439-451.