Homologous recombination repairs DNA damage, facilitates DNA replication, and creates the physical connections between chromosomes needed for reductional chromosome segregation during meiosis. We study two key recombination proteins, Dmc1 and Rad51 that are related to the central bacterial recombination protein, RecA. The mechanisms of recombinational repair of damage induced double strand breaks in DNA (DSBs) and the mechanism of meiotic recombination are very closely related in terms of the DNA intermediates that form; DSBs are normal intermediates in most or all meiotic recombination.
There are, however critical differences in how meiotic recombination is regulated as compared to mitotic recombinational repair. Our research is directed at understanding how Dmc1's function is specialized for meiosis, how the functions of Rad51 and Dmc1 differ, how the two proteins interact with one another during meiosis, and how the two proteins interact with components of the synaptonemal complex, a meiosis-specific chromosome scaffold. Our studies show that Rad51, which serves as the central “recombinase” in mitotic cells, is converted to a Dmc1 accessory protein in meiosis.
Our current approaches to understanding Rad51 and Dmc1 function include biochemical reconstitution of Dmc1 activity. This work currently involves 7 meiotic recombination proteins. We were first to show that recombination proteins can be detected at multiple subnuclear sites during recombination using immunostaining techniques. We have used cytological methods in the past to identify proteins required for recruitment of recombinase to double strand break sites in mitotic and meiotic cells. These regulators include the breast cancer susceptibility genes BRCA1 and BRCA2, which promote the assembly of recombination complexes, and RAD54 family translocases, which promote disassembly. We recently began to focus our cytological efforts on super-resolution light microscopy methods including STORM and STED. These methods are shedding new light on the architecture of the recombinosome. Finally we use molecular genetic techniques that allow detection of DNA recombination intermediates to study the mechanism that regulate meiotic recombination in living cells.
Harvard University
Cambridge, MA
Ph. D. - Cell and Developmental Biology
1988
Amherst College
Amherst, MA
B.A. - Biology
1980
How strand exchange protein function benefits from ATP hydrolysis.
How strand exchange protein function benefits from ATP hydrolysis. Curr Opin Genet Dev. 2021 12; 71:120-128.
PMID: 34343922
Meiosis in Quarantine discussions lead to an action plan to increase diversity and inclusion within the genetics community.
Meiosis in Quarantine discussions lead to an action plan to increase diversity and inclusion within the genetics community. PLoS Genet. 2021 07; 17(7):e1009648.
PMID: 34264967
A mutant form of Dmc1 that bypasses the requirement for accessory protein Mei5-Sae3 reveals independent activities of Mei5-Sae3 and Rad51 in Dmc1 filament stability.
A mutant form of Dmc1 that bypasses the requirement for accessory protein Mei5-Sae3 reveals independent activities of Mei5-Sae3 and Rad51 in Dmc1 filament stability. PLoS Genet. 2019 12; 15(12):e1008217.
PMID: 31790385
Distinct Functions in Regulation of Meiotic Crossovers for DNA Damage Response Clamp Loader Rad24(Rad17) and Mec1(ATR) Kinase.
Distinct Functions in Regulation of Meiotic Crossovers for DNA Damage Response Clamp Loader Rad24(Rad17) and Mec1(ATR) Kinase. Genetics. 2019 Dec 01; 213(4):1255-1269.
PMID: 33954522
Distinct Functions in Regulation of Meiotic Crossovers for DNA Damage Response Clamp Loader Rad24(Rad17) and Mec1(ATR) Kinase.
Distinct Functions in Regulation of Meiotic Crossovers for DNA Damage Response Clamp Loader Rad24(Rad17) and Mec1(ATR) Kinase. Genetics. 2019 12; 213(4):1255-1269.
PMID: 31597673
Non-enzymatic roles of human RAD51 at stalled replication forks.
Non-enzymatic roles of human RAD51 at stalled replication forks. Nat Commun. 2019 09 27; 10(1):4410.
PMID: 31562309
RPA resolves conflicting activities of accessory proteins during reconstitution of Dmc1-mediated meiotic recombination.
RPA resolves conflicting activities of accessory proteins during reconstitution of Dmc1-mediated meiotic recombination. Nucleic Acids Res. 2019 01 25; 47(2):747-761.
PMID: 30462332
The ATPase activity of E. coli RecA prevents accumulation of toxic complexes formed by erroneous binding to undamaged double stranded DNA.
The ATPase activity of E. coli RecA prevents accumulation of toxic complexes formed by erroneous binding to undamaged double stranded DNA. Nucleic Acids Res. 2018 10 12; 46(18):9510-9523.
PMID: 30137528
Purification of Saccharomyces cerevisiae Homologous Recombination Proteins Dmc1 and Rdh54/Tid1 and a Fluorescent D-Loop Assay.
Purification of Saccharomyces cerevisiae Homologous Recombination Proteins Dmc1 and Rdh54/Tid1 and a Fluorescent D-Loop Assay. Methods Enzymol. 2018; 600:307-320.
PMID: 29458764
Microbial Tuning of the Mammalian Immune System.
Microbial Tuning of the Mammalian Immune System. Trends Mol Med. 2017 05; 23(5):379-380.
PMID: 33954551