Structure and Dynamics of the Synaptonemal Complex

描述（由申请人提供）：

DESCRIPTION (provided by applicant): Project Summary/Abstract During meiotic prophase, homology recognition between partner chromosomes is coordinated with the assembly of a proteinaceous scaffold, the synaptonemal complex (SC), along the length of the chromosome pair (synapsis). Interhomolog recombination progresses within the context of assembled SC, and many interhomolog recombination events rely on SC for their proper distribution and/or completion. Our lab investigates SC structure and how SC assembly is coordinated with meiotic prophase chromosomal events. Recently we demonstrated that In S. cerevisiae, at least some components of the SC remain dynamic during meiotic prophase, even after chromosomes are fully synapsed. Moreover we found that recombination sites maintain a different SC dynamic as compared to other sites on the SC. Furthermore, our preliminary studies show that SUMO, which localizes to SC structures, has a mutually dependent relationship with the coiled-coil Zip1 protein to assemble SC on meiotic chromosomes. With pioneering imaging studies using super-resolution light microscopy, we have also shown that SUMO localizes to Zip1 N termini, at the center of SC structure. Finally, the lab has isolated zip1 alleles that assemble on chromosomes independent of canonical regulators. Each zip1 allele represents a single amino acid substitution at the extreme C terminus of Zip1 and may reveal aspects of the mechanism underlying Zip1 assembly. The purpose of this grant proposal is to 1) use our established genetic and microscopy tools to define the molecular architecture and dynamics of all known synapsis proteins within the SC, and 2) to isolate point mutant alleles of synapsis initiation proteins and Zip1 in order to identif molecular features of each protein responsible for their function in synapsis and other meiotic prophase chromosomal events.