Failure to achieve accurate chromosome segregation during meiosis is a leading cause of miscarriages, infertility, and birth defects such as Down syndrome. Therefore, understanding the mechanisms underlying accurate chromosome segregation during meiosis is of paramount importance to human health. The synaptonemal complex (SC) is a zipper-like structure ubiquitously present during meiosis from yeast to humans where it assembles between homologous chromosomes stabilizing homologous pairing interactions and promoting interhomolog crossover formation. However, despite its importance for key events required for accurate chromosome segregation during meiosis, the mechanisms regulating chromosome synapsis are not well understood in any organism. Moreover, studies focused on the post-translational regulation of proteins forming this structure are uncovering novel roles for the SC, linking it to the regulation of DSB formation and crossover designation. These recent findings further underscore the importance of this structure and of uncovering the roles it plays during meiosis. Our goal is to address these critical issues by taking advantage of the ease of genetic, cytological, molecular and biochemical analysis that is afforded by the use of the nematode C. elegans, an ideal model system for germline studies. Our progress during the previous funding period, coupled with new data and molecular targets, place us in an ideal position to understand the regulation of chromosome synapsis and the roles exerted by the SC during meiosis. Here we propose two integrated aims to address these critical issues.
Aim 1 will address how ATM/ATR-mediated phosphorylation of SYP-4, a central region component of the SC, regulates SC dynamics, DNA double-strand break (DSB) repair, and crossover frequency and distribution.
Aim 2 will determine the mechanisms of function for GRAS-1, a new and conserved protein of previously unknown meiotic function, which our studies implicate in regulating SC assembly and we hypothesize may act as a molecular scaffold for structural components of the SC. We will also investigate the functional conservation shared between GRAS-1 and mammalian GRASP and CYTIP proteins, through combined studies in C. elegans and mice. These studies will shed new light on our understanding of the mechanisms regulating chromosome synapsis and the roles of the SC. Our studies are expected to impact multiple fields of tremendous relevance to human health including chromosome dynamics, the study of post-translational modifications, and regulation of macromolecular structures. Taken together, this application will provide significant new insights into the molecular mechanisms regulating accurate chromosome segregation during meiosis.

Public Health Relevance

Meiosis is a specialized cell division program that is essential for the formation of both eggs and sperm and therefore critically important for human reproductive health. Errors during meiosis are a leading cause of miscarriages, infertility and birth defects such as Down syndrome in humans. This application will investigate the regulation and the roles of the synaptonemal complex, a structure required for promoting accurate meiotic chromosome segregation in most organisms from yeast to humans, thereby laying the foundation for the development of effective preventive strategies.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM072551-15
Application #
10020986
Study Section
Cellular, Molecular and Integrative Reproduction Study Section (CMIR)
Program Officer
Gindhart, Joseph G
Project Start
2005-08-01
Project End
2023-07-31
Budget Start
2020-08-01
Budget End
2021-07-31
Support Year
15
Fiscal Year
2020
Total Cost
Indirect Cost
Name
Harvard Medical School
Department
Genetics
Type
Schools of Medicine
DUNS #
047006379
City
Boston
State
MA
Country
United States
Zip Code
02115
Ferrandiz, Nuria; Barroso, Consuelo; Telecan, Oana et al. (2018) Spatiotemporal regulation of Aurora B recruitment ensures release of cohesion during C. elegans oocyte meiosis. Nat Commun 9:834
Gao, Jinmin; Colaiácovo, Monica P (2018) Zipping and Unzipping: Protein Modifications Regulating Synaptonemal Complex Dynamics. Trends Genet 34:232-245
Tzur, Yonatan B; Winter, Eitan; Gao, Jinmin et al. (2018) Spatiotemporal Gene Expression Analysis of the Caenorhabditis elegans Germline Uncovers a Syncytial Expression Switch. Genetics 210:587-605
Nadarajan, Saravanapriah; Lambert, Talley J; Altendorfer, Elisabeth et al. (2017) Polo-like kinase-dependent phosphorylation of the synaptonemal complex protein SYP-4 regulates double-strand break formation through a negative feedback loop. Elife 6:
Nottke, Amanda C; Kim, Hyun-Min; Colaiácovo, Monica P (2017) Wrestling with Chromosomes: The Roles of SUMO During Meiosis. Adv Exp Med Biol 963:185-196
Gao, Jinmin; Barroso, Consuelo; Zhang, Pan et al. (2016) N-terminal acetylation promotes synaptonemal complex assembly in C. elegans. Genes Dev 30:2404-2416
Kim, Hyun-Min; Colaiácovo, Monica P (2016) CRISPR-Cas9-Guided Genome Engineering in C. elegans. Curr Protoc Mol Biol 115:31.7.1-31.7.18
Nadarajan, Saravanapriah; Mohideen, Firaz; Tzur, Yonatan B et al. (2016) The MAP kinase pathway coordinates crossover designation with disassembly of synaptonemal complex proteins during meiosis. Elife 5:e12039
Kim, Hyun-Min; Colaiácovo, Monica P (2015) New Insights into the Post-Translational Regulation of DNA Damage Response and Double-Strand Break Repair in Caenorhabditis elegans. Genetics 200:495-504
Mendes, Tasha K; Novakovic, Stevan; Raymant, Greta et al. (2015) Investigating the role of RIO protein kinases in Caenorhabditis elegans. PLoS One 10:e0117444

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