Crossovers direct the accurate segregation of meiotic chromosomes. Several decades of effort has led to an understanding of many aspects of the meiotic recombination pathway, especially in S. cerevisiae. Although the early steps in meiotic recombination appear to be universal, there is clear variation in the processes that actually generate crossovers. A thorough understanding of meiotic recombination will therefore require studies in multiple model systems. This proposal takes advantage of features of Drosophila melanogaster that make certain experiments possible that are not possible in other model organisms. We will map the structures of recombination intermediates and products at high resolution by preserving heteroduplex DNA with dense marker spacing. We will also analyze both products of reciprocal crossovers to map gene conversion tracts. To better understand crossover control, we will test hypotheses for functions of a set of genes that encode MCM-like proteins essential for crossover formation, using a combination of genetic, biochemical, and cytological approaches. Finally, we will also study the late stages of the recombination process. Having identified a major Holliday junction resolvase complex, we will now ask whether other putative resolvases play a role in generating meiotic crossovers. These experiments will illuminate previously unknown features of meiotic recombination and further our understanding of the degree to which different species have selected alternative branches of DNA repair pathways to effect meiotic recombination.

Public Health Relevance

Meiosis is a specialized cell division that is used to make specialized cells, such as eggs, sperm, or spores that allow sexual reproduction. Recombination - the exchange of DNA between maternal and paternal chromosomes - is a crucial part of meiosis. This project seeks to better understand the complex mechanisms of DNA recombination, through genetic, cytological, and biochemical experiments that use the fruit fly as a model organism.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM061252-12
Application #
8293375
Study Section
Molecular Genetics C Study Section (MGC)
Program Officer
Janes, Daniel E
Project Start
2000-05-01
Project End
2014-06-30
Budget Start
2012-07-01
Budget End
2013-06-30
Support Year
12
Fiscal Year
2012
Total Cost
$305,258
Indirect Cost
$97,358
Name
University of North Carolina Chapel Hill
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
608195277
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Kuo, H Kenny; McMahan, Susan; Rota, Christopher M et al. (2014) Drosophila FANCM helicase prevents spontaneous mitotic crossovers generated by the MUS81 and SLX1 nucleases. Genetics 198:935-45
Crown, K Nicole; McMahan, Susan; Sekelsky, Jeff (2014) Eliminating both canonical and short-patch mismatch repair in Drosophila melanogaster suggests a new meiotic recombination model. PLoS Genet 10:e1004583
LaFave, Matthew C; Andersen, Sabrina L; Stoffregen, Eric P et al. (2014) Sources and structures of mitotic crossovers that arise when BLM helicase is absent in Drosophila. Genetics 196:107-18
Kohl, Kathryn P; Sekelsky, Jeff (2013) Meiotic and mitotic recombination in meiosis. Genetics 194:327-34
Lake, Cathleen M; Holsclaw, Julie Korda; Bellendir, Stephanie P et al. (2013) The development of a monoclonal antibody recognizing the Drosophila melanogaster phosphorylated histone H2A variant (ýý-H2AV). G3 (Bethesda) 3:1539-43
McMahan, Susan; Kohl, Kathryn P; Sekelsky, Jeff (2013) Variation in meiotic recombination frequencies between allelic transgenes inserted at different sites in the Drosophila melanogaster genome. G3 (Bethesda) 3:1419-27
Crown, K Nicole; Sekelsky, Jeff (2013) Targeted gene replacement in Drosophila goes the distance. Genetics 193:377-81
LaFave, Matthew C; Sekelsky, Jeff (2011) Transcription initiation from within P elements generates hypomorphic mutations in Drosophila melanogaster. Genetics 188:749-52
Andersen, Sabrina L; Sekelsky, Jeff (2010) Meiotic versus mitotic recombination: two different routes for double-strand break repair: the different functions of meiotic versus mitotic DSB repair are reflected in different pathway usage and different outcomes. Bioessays 32:1058-66
Mukherjee, Sushmita; LaFave, Matthew C; Sekelsky, Jeff (2009) DNA damage responses in Drosophila nbs mutants with reduced or altered NBS function. DNA Repair (Amst) 8:803-12

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