Tulle Hazelrigg

Germ Cell Development in Drosophila.

My lab addresses basic questions about the propagation and differentiation of germ cells, using Drosophila. Germ cells protect, rearrange and pass on a species’ genome to the next generation. They undergo complex differentiation to become highly specialized cell types, the gametes. In Drosophila, as in other organisms, the development of the germ cells begins with germ stem cells. Each time a germ stem cell divides, one daughter cell retains the stem cell fate, while the other enters the oogenesis or spermatogenesis pathway. We are interested in how genes are regulated in germ stem cells and differentiating germ cells, and in particular the role of epigenetic factors in the biology of these cells.

Much of our recent work stems from our discovery of a gene eggless (egg, also called dSetDB1) that is needed in germ cells. The protein from the gene, Egg, is required for methylation of histone H3 at its K9 residue (H3K9), during both oogenesis and spermatogenesis. We have recently shown that in the absence of the gene, germ stem cells are not maintained in adult flies, in both the ovaries and the testes. We are testing the hypothesis that the Egg protein normally establishes repressive chromatin domains at the promoters of specific genes, thereby establishing the necessary temporal pattern of gene expression in germ stem cells and their daughters. Current experiments are focused on identifying the direct gene targets of Egg, and the mechanism by which Egg finds these targets in the genome.

Course: Biol W1130y - Genes and Development

MedLine Listing of Dr. Hazelrigg's Publications

• Clough, E., Tedeschi, T. and Hazelrigg, T. 2014. Epigenetic regulation of oogenesis and germ stem cell maintenance by the Drosophila histone methyltransferase Eggless/dSetDB1. Dev Biol. 388(2):181-91.
• Clough, E., Moon, W., Wang, S., Smith, K., and Hazelrigg, T.(2007) Histone methylation is required for oogenesis in Drosophila. Development. Jan 134(1): 157-65.
• Hazelrigg, T., and Mansfield, J H. (2006) Green Fluorescent Protein Applications in Drosophila. Methods Biochem Anal 47: 227-57.
• Moon, W., and Hazelrigg, T. (2004) The Drosophila microtubule-associated protein Mini Spindles is required for cytoplasmic microtubules in oogenesis. Curr. Biol 14: 1957-1961.
• Mansfield, J., Wilhelm, J.E., and Hazelrigg, T. (2002) Ypsilon Schactel, a Drosophila Y-box protein, acts antagonistically to Orb in the oskar mRNA localization and translation pathway Development 129: 197-209.
• Brent, A., MacQueen, A., and T. Hazelrigg (2000) The Drosophila wispy gene is required for RNA localization and other microtubule-based events of meiosis and early embryogenesis Genetics 154: 1649-1662.
• Wilhelm, J., Mansfield, J., Hom-Booher, N., Wang, S., Turck, C.W., Hazelrigg, T., and Vale, R. (2000) Isolation of a Ribonucleoprotein complex involved in mRNA localization in Drosophila oocytes J. Cell Biol. 148: 427-440.
• Wang S, Hazelrigg T. (1994) Implications for bcd mRNA localization from spatial distribution of exu protein in Drosophila oogenesis. Nature. Jun 2;369(6479):400-03.