Spo11 Background Information Meiotic recombination in Saccharomyces cerevisiae is initiated by programmed DNA double-strand breaks (DSBs), a process that requires the Spo11 protein (1,2). DSBs usually occur in intergenic regions that display open chromatin accessibility (1). Spo11p is related to a subunit of archaebacterial topoisomerase VI and appears to cleave DNA through a topoisomerase-like transesterase mechanism (2). Formation of the DSBs that initiate meiotic recombination requires the products of at least 10 genes (3). Spo11 may be the catalytic subunit of the DNA cleaving activity (3). Studies in fission yeast, multicellular fungi, flies, worms, plants, and mammals indicate that the role of Spo11 in meiotic recombination initiation is highly conserved (4). Spo11 is a nuclear protein belonging to the TOP6A family (5).
