Spo11induced

Spo11induced refers to the double-strand breaks created by the meiotic protein Spo11, which initiates homologous recombination during meiosis in eukaryotes. Spo11 catalyzes the cleavage of DNA and remains covalently attached to the 5' ends, marking sites of breakage at preferred genomic locations known as hotspots. Accessory factors such as Rec114, Mer2, Mei4, and Spp1 help specify break sites and promote the assembly of the recombination machinery.

After break formation, Spo11-bound ends are processed by the MRX (Mre11-Rad50-Xrs2 in yeast) or MRN (Mre11-Rad50-Nbs1 in vertebrates) complex together with Sae2/CtIP to resect the DNA and generate 3' single-stranded tails. These tails are coated by the recombinases Rad51 and Dmc1, which drive strand invasion into a homologous chromosome, initiating repair through meiotic recombination pathways. Repair can yield crossovers or non-crossovers; crossovers establish chiasmata that help ensure proper homolog segregation, while non-crossovers preserve genetic information without exchanging flanking sequences.

The distribution and frequency of Spo11induced DSBs are influenced by chromatin context and chromosome axis components, including histone marks such as H3K4me3 via Spp1 and the synaptonemal complex. Checkpoint kinases related to ATM/ATR monitor DSB formation and repair during meiotic progression, helping to coordinate timely recombination with meiosis.

In summary, Spo11induced DSBs are a central initiating event in meiotic recombination, driving genetic diversity and accurate chromosome behavior. Misregulation or failure to repair these breaks can lead to defective recombination and genome instability.