| Biochemistry
of homologous recombination 
Characterization
of recombinase function in vivo
Characterization
of DNA intermediates in meiotic recombination
Genetic dissection
of BRCA1 function
Intergenic suppression
of BRCA1 function
Characterization
of drugs that alter the efficiency of homologous recombination
The recombinase Dmc1 is only
expressed in meiotic cells. Given that meiotic recombination has
unique properties as compared to mitotic recombination, it is
attractive to hypothesize that one or more meiosis-specific properties
are conferred by the meiosis-specific recombinase. In this regard,
our group and others found evidence that Dmc1 is required for
normal levels of two key meiosis-specific properties: homologue
partner choice and crossover interference. However, the mechanism
through which Dmc1 contributes to these processes is not yet clear.
A budding yeast nucleus
at the pachytene stage of meiosis. The nucleus is surface
spread and immunostained for Zip1, a component of the synaptonemal
complex.
We are taking two approaches
to characterizing Dmc1 function in meiotic cells. First, we are
taking a classical genetic approach to look for intergenic suppressors
of temperature-sensitive dmc1 alleles. This screen identified
four complementation groups of suppressors. We are in the process
of mapping these genes. Our second approach to Dmc1 function is
to determine the topology of the complexes formed by Dmc1 with
respect to those formed by other recombination proteins as well
as proteins that contribute to the structural organization of
meiotic chromosomes.
A zygotene nucleus
surface spread and double immunostained for Rad51 (red) and Dmc1
(green). Image shows that the two recombinases form side-by-side
pairs of foci. (Shinohara
et al. Proc Natl Acad Sci U S A. 2000 Sep 26;97(20):10814-9.)
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