People

Douglas K. Bishop, PhD

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

Distinct Functions in Regulation of Meiotic Crossovers for DNA Damage Response Clamp Loader Rad24(Rad17) and Mec1(ATR) Kinase.
Shinohara M, Bishop DK, Shinohara A. Distinct Functions in Regulation of Meiotic Crossovers for DNA Damage Response Clamp Loader Rad24(Rad17) and Mec1(ATR) Kinase. Genetics. 2019 Oct 09.
PMID: 31597673

Non-enzymatic roles of human RAD51 at stalled replication forks.
Mason JM, Chan YL, Weichselbaum RW, Bishop DK. Non-enzymatic roles of human RAD51 at stalled replication forks. Nat Commun. 2019 Sep 27; 10(1):4410.
PMID: 31562309

RPA resolves conflicting activities of accessory proteins during reconstitution of Dmc1-mediated meiotic recombination.
Chan YL, Zhang A, Weissman BP, Bishop DK. 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.
Gataulin DV, Carey JN, Li J, Shah P, Grubb JT, Bishop DK. 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.
Chan YL, Bishop DK. 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

Small Rad51 and Dmc1 Complexes Often Co-occupy Both Ends of a Meiotic DNA Double Strand Break.
Brown MS, Grubb J, Zhang A, Rust MJ, Bishop DK. Small Rad51 and Dmc1 Complexes Often Co-occupy Both Ends of a Meiotic DNA Double Strand Break. PLoS Genet. 2015 Dec; 11(12):e1005653.
PMID: 26719980

Surface Spreading and Immunostaining of Yeast Chromosomes.
Grubb J, Brown MS, Bishop DK. Surface Spreading and Immunostaining of Yeast Chromosomes. J Vis Exp. 2015 Aug 09; (102):e53081.
PMID: 26325523

Caffeine inhibits gene conversion by displacing Rad51 from ssDNA.
Tsabar M, Mason JM, Chan YL, Bishop DK, Haber JE. Caffeine inhibits gene conversion by displacing Rad51 from ssDNA. Nucleic Acids Res. 2015 Aug 18; 43(14):6902-18.
PMID: 26019181

Caffeine impairs resection during DNA break repair by reducing the levels of nucleases Sae2 and Dna2.
Tsabar M, Eapen VV, Mason JM, Memisoglu G, Waterman DP, Long MJ, Bishop DK, Haber JE. Caffeine impairs resection during DNA break repair by reducing the levels of nucleases Sae2 and Dna2. Nucleic Acids Res. 2015 Aug 18; 43(14):6889-901.
PMID: 26019182

RAD54 family translocases counter genotoxic effects of RAD51 in human tumor cells.
Mason JM, Dusad K, Wright WD, Grubb J, Budke B, Heyer WD, Connell PP, Weichselbaum RR, Bishop DK. RAD54 family translocases counter genotoxic effects of RAD51 in human tumor cells. Nucleic Acids Res. 2015 Mar 31; 43(6):3180-96.
PMID: 25765654

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