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
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 helped show that these two hermaphroditic species are not closely related, and colleagues recently discovered a third type of hermaphrodite. Thus, mating systems must have changed multiple times during the evolution of this group.
Using RNA interference, we showed that this transition involved two types of changes: the initiation of spermatogenesis in XX animals, and the production of signal that activates these sperm so they can fertilize oocytes. We are studying these changes by creating custom mutations in a variety of nematode species, and by isolating new mutations that affect self-fertilization.
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 mutations cause all germ cells to become oocytes. We showed that FOG-1 is a Cytoplasmic Polyadenylation Element binding protein, and that FOG-3 is related to the Tob proteins of other animals. We are now studying how these two proteins cooperate to turn on spermatogenesis and block oogenesis.
1. Wei Q, Zhao Y, Guo Y, Stomel J, Stires R, Ellis RE."Co-option of alternate sperm activation programs in the evolution of self-fertile nematodes." Nat Commun. 2014 Dec 19;5:5888. doi: 10.1038/ncomms6888.
2. Wei Q, Shen Y, Chen X, Shifman Y, and Ellis RE. 2014. "Rapid creation of forward- genetics tools for C. briggsae using TALENs: Lessons for non-model organisms" Mol. Biol. Evol. 31(2): 468-73
3. Chu HP, Liao Y, Novak JS, Hu Z, Merkin JJ, Shymkiv Y, Braeckman BP, Dorovkov MV, Nguyen A, Clifford PM, Nagele RG, Harrison DE, Ellis R.E, Ryazanov AG. 2014. " Germline Quality Control:eEF2K Stands Guard to Eliminate Defective Oocytes. " Dev Cell 28(5): 561-72
4. Chen X, Shen Y and Ellis RE. 2014. "Dependence of the sperm/oocyte decison on the Nuclersome Remodeling Factor Complex was acquired during recent C. briggsae evolution." Mol. Biol. Evol. 31(10): 2573-2585.
5. Guo Y, Chen X and Ellis RE. 2013. "Evolutionary change within a bipotential switch shaped the sperm/oocyte decision in hrmaphroditic nematodes." PloS Genet. 9:e1003850.
6. Baldi, C., Viviano, J. and Ellis, RE. 2011." A bias caused by ectopic development produces sexually dimorphic sperm in nematodes." Curr. Biol. 21: 1416-1420.
7. Nakano, S., Ellis, RE. and Horvitz, H. R. 2010. "Otx dependent Expression of Proneural bHLH Genes Establishes a Neuronal Bilateral Asymmetry in C. elegans." Development. 137: 4017-27.
8. Guo, Y, Lang, S and Ellis, RE. 2009. "Independent Recruitment of F-box Genes to Regulate Hermaphrodite Development During Nematode Evolution." Curr. Biol. 19: 1853-60.
9. Baldi, C., Cho, Soochin and Ellis, RE. 2009. "Mutations in Two Independent Pathways are Sufficient to Create Hermaphroditic Nematodes." Science. 326: 1002-5.
10. Hiatt SM, Duren HM, Shyu YJ, Ellis RE, Hisamoto N, Matsumoto K, Kariya K, Kerppola TK, Hu CD. "Caenorhabditis elegans FOS-1 and JUN-1 regulate plc-1 expression in the spermatheca to control ovulation." Mol Biol Cell. 2009 Sep;20(17):3888-95. doi: 10.1091/mbc.E08-08-0833. Epub 2009 Jul 1.
11. Andux, S. and Ellis, RE. 2008. "Apoptosis maintains oocyte quality in aging Caenorhabditis elegans females." PLoS Genet 4: e1000295.
12. Shyu, Y. J., Hiatt, S. M., Duren, H. M., Ellis, RE., 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.
13. Shen, X., Ellis, RE., 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.
14. Cho, S., Jin, S.-W., Cohen, A. and Ellis, RE. 2004. “A phylogeny of Caenorhabditis reveals frequent loss of introns during nematode evolution.” Genome Res. 14: 1207-1220.
15. Gray, J. M., Karow, D. S., Lu, H., Chang, A. J., Chang, J. S., Ellis, RE., 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 RE, Wei Q. Size isn't everything. Elife 2015 April; 4. doi. 10.7554/elife.07604.
Ellis RE and Stanfield G. 2014. The regulation of spermatogenesis and sperm function in nematodes. Sem. Cell Dev. Biol. 29:17-30
Ellis RE and Scharer L. 2014 Rogue sperm indicate sexually antagonistic co-evolution in nematodes. PLoS Biol. 12:e1001916
Ellis RE and Lin S-L. 2014. The evolution of self-fertility in nematodes. F1000 Prime Rep. 6:62.
Ellis RE and Chen X. 2013. Sex determination: How worms count to two. Current Biology 23:R573-R575.
Ellis, RE. 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, RE. 2010." The Sperm/Oocyte Decision, a C. elegans Perspective." in Oogenesis — The Universal Process of Oogenesis. ed. Marie-Hélène Verlhac. pp. 3-24.
Ellis, RE. 2010. “Chemically reprogramming cell fates.” Nat Chem Biol. 6: 84-85.
Ellis, RE. and Wei, Q. 2010. "Somatic signals counteract reproductive aging in females." Genome Biology 11: 142.
White-Cooper, H., K. Doggett and RE. 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, RE. 2008. Chapter 2" Sex Determination in the Caenorhabditis elegans Germ Line." Curr Top Dev Biol 83: 41-64.
Ellis, RE. 2006. “Enigma variations: control of sexual fate in nematode germ cells.” Genome Biol. 7: 227.
Ellis, RE. and Schedl, T. 2006." Sex Determination in the Germ Line." in The WormBook. ed Marty Chalfie et al. WormBase.