UC Berkeley

Sexual reproduction requires meiosis, the unique cell division in which haploid

gametes are generated from a diploid cell. A hallmark of meiotic prophase is the formation of pairwise linkages between homologous chromosomes, which later enable them to segregate away from each other at meiosis I. In most organisms the pairing of homologous chromosomes is reinforced by polymerization of the synaptonemal complex (SC) between paired chromosome axes, or synapsis. The primary questions addressed in this study are: 1) how pairing is accomplished and 2) how synapsis is regulated so that it occurs selectively between homologs. In Chapter I, I present evidence that a bridge of the nuclear envelope proteins comprised of SUN-1 and ZYG-12 connects meiotic chromosomes to the microtubule cytoskeleton, and this connection spanning the nuclear envelope is critical for coordinating homolog pairing and synapsis. I propose a model in which dynein-based forces are used to assess homology between chromosomes and to license subsequent chromosome interactions during meiotic prophase. In Chapter 2, I identify a novel Pairing Center-interacting protein DPY-30 and present my characterization of the germline in a dpy-30 mutant. I explore different possibilities to investigate the functional significance of the interaction between DPY-30 and Pairing Center proteins. I discuss possible roles of DPY-30 in early meiosis based on my preliminary results.