Molecular Genetics of Recombination

Abstract

The biochemistry of eukaryotic homologous recombination caught fire with the discovery that Rad51 is the eukaryotic homolog of the bacterial RecA and T4 UvsX proteins; and this field is still hot. The core reaction of homologous recombination, homology search and DNA strand invasion, along with the proteins catalyzing it, are conserved throughout evolution in principle. However, the increased complexity of eukaryotic genomes and the diversity of eukaryotic cell biology pose additional challenges to the recombination machinery. It is not surprising that this increase in complexity coincided with the evolution of new recombination proteins and novel support pathways, as well as changes in the properties of those eukaryotic recombination proteins that are evidently conserved in evolution. In humans, defects in homologous recombination lead to increased cancer predisposition, underlining the importance of this pathway for genomic stability and tumor suppression. This review will focus on the mechanisms of homologous recombination in eukaryotes as elucidated by the biochemical analysis of yeast and human proteins.

Single-Molecule Views of Protein Movement on Single-Stranded DNA

“…A single color fluorescence detection experiment using protein-induced fluorescence enhancement also supports RecA binding to and dissociation from a filament as a monomer (54). Although Rad51 is expected to behave in similar ways to RecA, there is presently no consensus in the directionality of Rad51 filament formation(49) but recent studies are more consistent with the 3’ to 5’ direction, which would be opposite to that of RecA(4; 110). Indirect evidence based on Rad51 filament dissociation from long dsDNA supports the notion that the unit for disassembly is a monomer(135), and magnetic tweezers studies of Rad51 filament formation directly detected monomeric extension through a stepwise twisting of the DNA(5).…”

Meta‐analysis of chromosome‐scale crossover rate variation in eukaryotes and its significance to evolutionary genomics

“…This involves numerous programmed DNA doublestrand breaks and the invasion of short single-stranded DNA segments into the homologous chromosome. A small fraction of the DNA breaks are then repaired as crossovers (CO), the reciprocal exchange of DNA segments between the homologous chromosomes (Hunter, 2007; CO is thus only one aspect of recombination, and hence, these two terms are not used interchangeably in this study).CO is an intriguing biological process because of its dual mechanistic and evolutionary implications. On the one hand, the segregation of *Quiterie Haenel and Telma G. Laurentino share first authorship, alphabetical order.…”

Reconstituted System for the Examination of Repair DNA Synthesis in Homologous Recombination

“…D-loop formation by the presynaptic filament is enhanced by associated factors including the Swi2/Snf2 family proteins Rad54 and Rdh54 and the ssDNA binding protein RPA (Daley, Gaines, Kwon, & Sung, 2014; Heyer, 2007). Following strand invasion, de novo DNA synthesis occurs within the D-loop.…”