Biochemistry of Meiotic Recombination
Analysis of the structural architecture of meiotic recombination complexes
Characterization of the mechanism of homolog bias in meiosis
Role of Rad51 in genome stability and cancer
Small molecule stimulators of Rad51-DNA binding
Our group pioneered the use of fluorescence microscopy in the study of homologous recombination (Bishop 94). With appropriate immunostaining or GFP, strand exchange proteins Rad51 and Dmc1 can be visualized as subnuclear foci. This method was first used to show that Rad51 and Dmc1 localize to the same subnuclear sites and that normal localization of Dmc1 depends on Rad51. We have since used this method to identify additional factors that promote the assembly or disassembly of Rad51 and Dmc1 during recombination. For example, we showed that the breast cancer susceptibility gene BRCA1 is required for recruitment of RAD51 to sites of DNA damage (Bhattacharya et al. 2000). We recently began to employ super-resolution light microscopy methods such as stimulated emission depletion microscopy (STED) and stochastic optical reconstruction microscopy (STORM) for our studies of recombinosome structure. These methods are particularly well suited for the analysis of recombinosomes when combined with chromosome spreading techniques. Unexpected properties of the recombinosome are being revealed by this approach.
Immunostaining for Rad51 and Dmc1. The image shows the staining pattern of a single nucleus. Note that foci of Rad51 and Dmc1 are found to partially overlap suggesting that these proteins form side-by-side homofilaments (adapted from Shinohara et al. 2000). This image was obtained by standard widefield epifluorescence microscopy.
Bishop, D.K. (1994) RecA Homologues Dmc1 and Rad51 Interact to Form Multiple Nuclear Complexes Before Meiotic Chromosome Synapsis. Cell 79, 1081-1092
Shinohara, M., Gasior, S. L., Bishop, D.K., and Shinohara, A. (2000) Tid1/Rdh54 and Red1 Promote Colocalization of RecA Homologs Rad51 And Dmc1 During Meiotic Recombination. Proc. Natl. Acad. Sci, USA 97, 10814-10819
Bhattacharyya, A., Ear, U., Koller, B., Weichselbaum, R. and Bishop, D. K. (2000) The Breast Cancer-Susceptibility Gene BRCA1 is Required for Subnuclear Assembly of Rad51 and Survival Following Treatment with the DNA Crosslinking Agent Cisplatin. J. Biol. Chem. 60, 2520-2526