Part I: Meiosis: an Overview
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In Part 1, Dr. Dernburg begins with an overview of meiosis, the process of cell division that gives rise to germ cells such as eggs, sperm, pollen and spores, and how it differs from mitosis. Dernburg explains that C. elegans is an excellent model system for studying meiosis because the gonads contain a complete temporal progression of meiotic stages. Development through pairing, synapsis, recombination and segregation can be followed easily since C. elegans are transparent. Taking advantage of the C. elegans system, Dernburg and her lab have studied the process of homolog pairing, an event that is specific to meiosis and required for recombination.
In her second and third lectures, Dernburg delves deeper into the question of how homologous pairs of chromosomes find each other and how they undergo pairing and synapsis. She describes how members of her lab found that each chromosome has a region called a pairing center that is required for homolog pairing. They were able to show that each pairing center recruits one of four related zinc finger proteins that, in turn, interact with the proteins SUN-1 and ZYG-12, which are anchored in the nuclear envelope. The cytosolic portion of ZYG-12 interacts with motor protein dynein forming a bridge or link between the chromosomes and the microtubule cystoskeleton. Using confocal imaging, Dernburg’s lab was able to track the movements of labeled chromosomes and their protein partners to try to decipher how these interactions lead to pairing and synapsis of chromosome homologs.
Abby Dernburg is an Investigator of the Howard Hughes Medical Institute, a Professor of Molecular and Cell Biology at the University of California, Berkeley and a Senior Scientist in the Life Sciences Division of Lawrence Berkeley National Laboratory.
Dernburg has studied different aspects of chromosome biology for many years, beginning with her PhD studies in the lab of John Sedat at the University of California, San Francisco. Dernburg moved to Anne Villeneuve’s lab at Stanford University for post-doctoral training. There she combined genetic studies and microscopy to begin her investigations of meiosis in C. elegans. Since establishing her own lab at Berkeley, Dernburg has continued to unravel the complex process of chromosome pairing during meiosis in C. elegans.
Dernburg has received numerous awards for her work including the Edward Novitski Award from the Genetics Society of America, an Early Career Life Scientist Award from the American Society of Cell Biology and the Presidential Early Career Award for Scientists and Engineers.
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Rog, O., and Dernburg, A.F. (2013). Chromosome pairing and synapsis during Caenorhabditis elegans meiosis. (Review). Curr Opin Cell Biol. DOI: 10.1016/j.ceb.2013.03.003
Wynne D.J., Rog O., Carlton P.M., Dernburg A.F. (2012). Dynein-dependent processive chromosome motions promote homologous pairing in C. elegans meiosis. J Cell Biol. 196:47-64. DOI: 10.1083/jcb.201106022
Sato, A., Isaac, B., Phillips, C.M., Rillo, R., Carlton., P.M., Wynne, D.J., Kasad, R., and Dernburg, A.F. (2009). Cytoskeletal forces span the nuclear envelope to coordinate meiotic chromosome pairing and synapsis. Cell, 139:907-19. DOI: 10.1016/j.cell.2009.10.039
Phillips, C.M., and Dernburg, A.F. (2006). A family of zinc finger proteins is required for chromosome-specific pairing and synapsis during meiosis in C. elegans. Developmental Cell, 11:817-829.
MacQueen, A.J., Phillips, C.M., Bhalla, N., Weiser, P., Villeneuve, A.M., and Dernburg, A.F. (2005). Chromosome sites play dual roles to establish homolog synapsis during meiosis in C. elegans. Cell 123:1037-50.
Page, S.L. and Hawley, R.S. (2003) Chromosome Choreography: The Meiotic Ballet. (Review). Science 301:785-789. DOI: 10.1126/science.1086605