Control of stem cells by diet: Diet and fertility are intimately connected in many, if not all, organisms. For example, severely starved or obese women often fail to ovulate. Yet, the underlying molecular and cellular mechanisms are poorly understood. Over the past several years, we have been exploring the question of how ovarian stem cells and their descendents sense and respond to diet in Drosophila, a highly tractable genetic model system. What signals mediate the effects of diet? What organs, tissues and cell types generate and receive each signal? How they are seamlessly integrated to control egg output? These are some of the questions we are addressing using a combination of genetic, molecular, and cell biological tools.

Control of meiotic maturation: Meiotic maturation is a key process in the development of oocytes, when they progress from an initial prophase I arrest into metaphase I. Both the timing and accuracy of this process are crucial to ensure that chromosomes will be properly segregated and that a viable gamete will be formed. It is well established that the status of Cdk1 activation is a key determinant of whether oocytes remain arrested in prophase I or progress into metaphase I, and multiple cell cycle regulators of this kinase are known. The molecular factors within the oocyte triggering the onset of meiotic maturation or how this process is influenced by diet, however, are much less well understood. My laboratory has identified a-endosulfine as a new factor playing a major role in the control of meiotic maturation in Drosophila. We also have evidence to suggest that the meiotic function of a-endosulfine is conserved in higher organisms.We are actively investigating the role of a-endosulfine and other factors in the control of meiotic maturation.

Research Keywords Stem cells, reproduction, fertility, oogenesis, diet, insulin, Drosophila, developmental biology, endocrinology, physiology, genetics

1988 - First place in college entrance exam for Biological Sciences, Universidade Federal de Minas Gerais (Brazil)

1990-1991 - Scientific Initiation Fellowship, Conselho Nacional de Pesquisas (Brazil)

1993-1995 - Miles Scholar Award, Bayer Corporation

1997-2000 - National Research Service Award, National Institutes of Health

2006 - Chancellor’s Award for Research, Vanderbilt University

2008 - Semifinalist, 2009 Early Career Scientist Competition, Howard Hughes Medical Institute (130 semifinalists selected from 2,100 applicants)

Ables, E. T., Drummond-Barbosa, D. A steroid hormone functions with chromatin remodeling factors to control germline stem cells in Drosophila. Submitted. 

LaFever, L., Feoktistov, A., Hsu, H.-J., Drummond-Barbosa, D. Specific roles of Target of Rapamycin in the control of stem cells and their progeny in the Drosophila ovary. Submitted.

Hsu, H.-J., Drummond-Barbosa, D. Insulin levels control female germline stem cell maintenance via the niche in Drosophila. Proc. Natl Acad. Sci. USA 106(4), 1117-1121, 2009. This paper was highlighted in Nature Reports Stem Cells and also featured in Faculty of 1000 Biology

Drummond-Barbosa, D. Stem cells, their niches and the systemic environment: an aging network. Genetics 180(4), 1787-1797, 2008.

Von Stetina, J. R., Tranguch, S., Dey, S. K., Lee, L. A., Cha, B., Drummond-Barbosa, D. a-Endosulfine is a conserved protein required for oocyte meiotic maturation in Drosophila. Development 135(22), 3697-3706, 2008.

Hsu, H.-J., LaFever, L., Drummond-Barbosa, D. Diet controls normal and tumorous germline stem cells via insulin-dependent and -independent mechanisms in Drosophila. Dev. Biol. 313(2), 700-712, 2008. This paper was featured in Faculty of 1000 Biology.

LaFever, L., Drummond-Barbosa, D. Direct control of stem cell division and germ line development by neural insulin in Drosophila. Science 309(5737), 1071-1073, 2005.

Drummond-Barbosa, D. Regulation of stem cell populations. In: Encyclopedia of Molecular Cell Biology and Molecular Medicine, Meyers, R. A. ed., v 12, 2005.

Drummond-Barbosa, D., Spradling, A. C. a-Endosulfine, a potential regulator of insulin secretion, is required for adult tissue growth control in Drosophila. Dev. Biol., 266(2), 310-21, 2004.

Drummond-Barbosa, D., Spradling, A. C. Stem cells and their progeny respond to nutritional changes during Drosophila oogenesis. Dev. Biol., 231(1), 265-78, 2001.

Spradling, A., Drummond-Barbosa, D., Kai, T. Stem cells find their niche. Nature, 414(6859), 98-104, 2001.

Spradling, A. C., de Cuevas, M., Drummond-Barbosa, D., Keyes, L., Lilly, M., Pepling, M., Xie, T. The Drosophila germarium: stem cells, germ line cysts, and oocytes. Cold Spring Harb. Symp. Quant. Biol., 62, 25-34, 1997.