PRDM9 drives the location and rapid evolution of recombination hotspots in salmonid fish.

In many eukaryotes, meiotic recombination occurs preferentially at discrete sites, called recombination hotspots. In various lineages, recombination hotspots are located in regions with promoter-like features and are evolutionarily stable. Conversely, in some mammals, hotspots are driven by PRDM9 that targets recombination away from promoters.

FIGNL1-FIRRM is essential for meiotic recombination and prevents DNA damage-independent RAD51 and DMC1 loading.

During meiosis, nucleoprotein filaments of the strand exchange proteins RAD51 and DMC1 are crucial for repairing SPO11-generated DNA double-strand breaks (DSBs) by homologous recombination (HR). A balanced activity of positive and negative RAD51/DMC1 regulators ensures proper recombination. Fidgetin-like 1 (FIGNL1) was previously shown to negatively regulate RAD51 in human cells.

"MeiQuant": An Integrated Tool for Analyzing Meiotic Prophase I Spread Images.

Immunocytochemical analysis of meiotic proteins on mouse chromosome spreads is one method of choice to study prophase I chromosome organization and homologous recombination. In recent decades, the development of microscopic approaches led to the production of a large number of images that monitor fluorescent proteins, defined as fluorescent objects, and a major challenge facing the community is the deep analysis of these fluorescent objects (measurement of object length, intensity, distance between objects, as well as foci identification, counting, and colocalization). We propose a set of tools designed from the macro language of the widely used image analysis software ImageJ (Schindelin et al.

Mutation hotspots during meiosis.

Multiple pathways generate mutations at sites of meiotic recombination in humans.

PRDM9 activity depends on HELLS and promotes local 5-hydroxymethylcytosine enrichment.

Meiotic recombination starts with the formation of DNA double-strand breaks (DSBs) at specific genomic locations that correspond to PRDM9-binding sites. The molecular steps occurring from PRDM9 binding to DSB formation are unknown. Using proteomic approaches to find PRDM9 partners, we identified HELLS, a member of the SNF2-like family of chromatin remodelers.