The DSBR and SDSA meiotic recombination models

The DSBR and SDSA meiotic recombination models. Single strands of DNA are shown as either green (parent 1) or yellow (parent 2) rods. The Spo11 complex initiates programmed DSBs. DSBs are resected 5’ to 3’ to produce single ssDNA tails. ssDNA tails invade the homologous template which is aided by the ssDNA filament forming proteins Dmc1 and Rad51. At this stage, intermediates can undergo DSBR (left), which is thought to produce primarily COs or SDSA (right), which only produces NCOs. Also shown is a pathway (center) describing aberrant JMs, that are hypothesized to either be resolved back to the strand invasion stage by Sgs1 or resolved as COs by the Mus81-Eme1 heterodimer []. In the DSBR pathway, strand invasion complexes are stabilized (possibly by ZMM proteins) to form SEIs. Prior to stabilization, Sgs1 could wire SEIs back to the strand invasion stage [, ]. The displaced strand, called a D-loop is captured by the resected break of opposite homolog and subsequent DNA synthesis results in a dHJ intermediate. This intermediate is resolved as a CO upon appropriate resolution of the two HJs. in the SDSA pathway, the invading strand dissociates after a patch of DNA synthesis. This strand then re-anneals to the original parent, resulting in repair of the DSB and a patch of heteroduplex DNA. This pathway is always resolved as a NCO, but it can result in GC.

Publication

Genetic Interference: Don’t Stand So Close to Me. (2010) Luke E Berchowitz, et al. Curr Genomics. 2010 Apr;11(2):91-102. Figure: F1. All organisms Drosophila melanogaster Homo sapiens Mus musculus Danio rerio Saccharomyces cerevisiae S288C

Disease mentions