Faculty and Research Interests
Ronald Ellis, PhD
Science Center 316
Fax: 856 566-6291
Massachusetts Institute of Technology, MA
PhD (Biology) , 1989
Michigan State University, MI
BS (Biochemistry and Microbiology) , 1983
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.
Baldi, C., Viviano, J. and Ellis, R. E. 2011. A bias caused by ectopic development produces sexually dimorphic sperm in nematodes. Curr. Biol. 21: 1416-1420.
Nakano, S., Ellis, R. E. and Horvitz, H. R. 2010. Otx dependent Expression of Proneural bHLH Genes Establishes a Neuronal Bilateral Asymmetry in C. elegans. Development. 137: 4017-27.
Guo, Y, Lang, S and Ellis, R. E. 2009. Independent Recruitment of F-box Genes to Regulate Hermaphrodite Development During Nematode Evolution. Curr. Biol. 19: 1853-60.
Baldi, C., Cho, Soochin and Ellis, R. E. 2009. Mutations in Two Independent Pathways are Sufficient to Create Hermaphroditic Nematodes. Science. 326: 1002-5.
Hiatt, S. M., Shyu, Y. J., Duren, H. M., Ellis, R. E., Hisamoto, N., Matsumoto, K., Kariya, K., Kerppola, T. K. and C.-D. Hu. 2009. C. elegans FOS-1 and JUN-1 regulate transcription of plc-1 in the spermatheca to control ovulation. Mol Biol Cell 20: 3888-95.
Andux, S. and Ellis, R. E. 2008. Apoptosis maintains oocyte quality in aging Caenorhabditis elegans females. PLoS Genet 4: e1000295.
Shyu, Y. J., Hiatt, S. M., Duren, H. M., Ellis, R. E., T.K. Kerppola, T. K. and C.-D. Hu. 2008. Visualization of protein interactions in living Caenorhabditis elegans using bimolecular fluorescence complementation (BiFC) analysis. Nature Protocols. 3: 588-586.
Shen, X., Ellis, R. E., Zhang, K., and R. J. Kaufman. 2005. Genetic
Interactions as a Consequence of Constitutive and Inducible Gene
Regulation Mediated by the Unfolded Protein Response in C. elegans. PLoS Genetics. 1: e37.
Cho, S., Jin, S.-W., Cohen, A. and Ellis, R. E. 2004. “A phylogeny of Caenorhabditis reveals frequent loss of introns during nematode evolution.” Genome Res. 14: 1207-1220.
Gray, J. M., Karow, D. S., Lu, H., Chang, A. J., Chang, J. S., Ellis, R. E., Marletta, M. A. and C. I. Bargmann. 2004. “Oxygen sensation and social feeding mediated by a C. elegans guanylate cyclase homologue.” Nature 430: 317-322.
Reviews and Book Chapters:
Ellis, R. E. and Guo, Y. 2011. Evolution of Self-fertile Hermaphrodites. In Evolutionary Biology – Concepts, Biodiversity, Macroevoluiton and Genome Evolution. ed. Pontarotti, P., pp 35-50
Ellis, R. E. 2010. The Sperm/Oocyte Decision, a C. elegans Perspective. in Oogenesis — The Universal Process of Oogenesis. ed. Marie-Hélène Verlhac. pp. 3-24.
Ellis, R.E. 2010. “Chemically reprogramming cell fates.” Nat Chem Biol. 6: 84-85.
Ellis, R.E. and Wei, Q. 2010. Somatic signals counteract reproductive aging in females. Genome Biology 11: 142.
White-Cooper, H., K. Doggett and R.E. Ellis. 2009. The evolution of spermatogenesis. In Sperm Biology : An Evolutionary Perspective. eds. Birkhead, T.R., D.J. Hosken and S. PItnick, pp. 151-183. Academic Press, Burlington, MA.
Ellis, R.E. 2008. Chapter 2 Sex Determination in the Caenorhabditis elegans Germ Line. Curr Top Dev Biol 83: 41-64.
Ellis, R.E. 2006. “Enigma variations: control of sexual fate in nematode germ cells.” Genome Biol. 7: 227.
Ellis, R. E. and Schedl, T. 2006. Sex Determination in the Germ Line. in The WormBook. ed Marty Chalfie et al. WormBase.