Molecular Biology

Faculty and Research Interests

Ronald Ellis, PhD

Associate Professor
Science Center 316
856 566-2768
Fax: 856 566-6291
ron.ellis@umdnj.edu

Education

Massachusetts Institute of Technology, MA
PhD (Biology) , 1989

Michigan State University, MI
BS (Biochemistry and Microbiology) , 1983

Research Interests

Control of Germ Cell Fate

Animals must produce sperm or eggs to reproduce. Although these cell types differ dramatically, they are produced from similar progenitors. Understanding how this process is controlled could revolutionize our ability to treat reproductive disorders and infertility in humans.

To learn how spermatogenesis and oogenesis are specified, we are studying the fog-1 and fog-3 genes of nematodes. We know these genes are required for germ cells to initiate spermatogenesis, because in mutants all germ cells instead become oocytes. We showed that FOG-1 is a Cytoplasmic Polyadenylation Element binding protein, and are now searching for its target messenger RNAs, to learn how they interact with FOG-1 to control germ cell fates. FOG-3 is related to the Tob proteins of other animals, and we are using it as a molecular model to elucidate how this conserved family of proteins functions.

Evolution of Hermaphroditism

Sexual traits are among the most rapidly changing features of each species. To learn how these changes take place, and how developmental pathways constrain which ones occur, we are studying the evolution of mating systems in nematodes.

The genus Caenorhabditis contains male/hermaphroditic species like C. elegans and C. briggsae, and male/female species like C. remanei. We characterized five genes from each species to develop a phylogeny of these animals, which shows that the two hermaphroditic species are not closely related. Thus, mating systems must have changed multiple times during the evolution of this group.

FOG-1 and FOG-3 have conserved roles specifying germ cell fate in each species, but the expression of fog-3 differs dramatically between XX females and XX hermaphrodites. We are studying how this regulation occurs in C. remanei and C. briggsae, to learn how their sexual development has been altered to create each mating system. Our results suggest that the structure of the regulatory pathways involved strongly influences what changes are possible.

Recent Publications

1. Shen, X., Ellis, R. E., Kurnit, D. M., Liu, C.-Y., Lee, K., Solomon, A., Morimoto, R., Yoshida, H., Mori, K. and R. J. Kaufman. 2001. Complementary signaling pathways regulate the Unfolded Protein Response and are required for C. elegans development. Cell. 107: 893-903
2. Gao, J., Estrada, L., Cho, S., Ellis, R. E. and J. L. Gorski 2001. The Caenorhabditis elegans ortholog of FGD1, the human Cdc42 GEF gene responsible for Faciogenital Dysplasia, is critical for excretory cell morphogenesis. Hum. Mol. Genetics. 10: 3049-3062.
3. Jin, S.-W., Arno, N., Cohen, A., Shah, A., Xu, Q., Chen, N. and Ellis, R. E. 2001. In C. elegans, the RNA-binding domains of the CPEB protein FOG-1 are needed to regulate germ cell fates. Genetics 159:1617-1630.
   Chen, P-J., Cho, S., Jin, S.-W. and Ellis, R. E. 2001. Specification of germ cell fates by FOG-3 has been conserved during nematode evolution. Genetics 158: 1513:1525.
4. Jin, S.-W., Kimble, J. and Ellis, R. E. 2001. Regulation of Cell Fate by a Novel Cytoplasmic Polyadenylation Element Binding protein in C. elegans. Dev. Biol. 229: 537-553.
   
5. Stansberry, J., Taylor, M. K., Baude, E. J., Chen, P.-J., Jin, S.-W., Ellis, R. E. and Uhler, M. 2001. Wild-type motility in nematodes requires a cGMP-dependent protein kinase. J. Neurochemistry 76: 1177-1187.
6. del Peso, L., Gonzalez, V. M., Inohara, N., Ellis, R. E. and Nunez, G. 2000. Disruption of the CED-9/CED-4 complex is a critical step for CED-3 activation and programmed cell death. J. Biol. Chem. 275: 27205-27211.
7. Chen, P.-J. and Ellis, R. E. 2000. TRA-1A regulates transcription of fog-3, which controls germ cell fate in C. elegans. Development 127: 3119-3129.
8. Chen, P.-J., Singal, A., Kimble, J. and Ellis, R. E. 2000. A novel member of the Tob family of proteins controls sexual fate in C. elegans germ cells." Dev. Biol. 217: 77-90.
9. Wu, D., Chen, P. J., Chen, S., Hu, Y., Nunez, G., and Ellis, R. E. 1999. C. elegans MAC-1, an essential member of the AAA family of ATPases, can bind CED-4 and prevent cell death. Development 126: 2021-2031.