title: High throughput sequencing reveals alterations in the recombination signatures with diminishing Spo11 activity.
abstract: Spo11 is the topoisomerase-like enzyme responsible for the induction of the meiosis-specific double strand breaks (DSBs), which initiates the recombination events responsible for proper chromosome segregation. Nineteen PCR-induced alleles of SPO11 were identified and characterized genetically and cytologically. Recombination, spore viability and synaptonemal complex (SC) formation were decreased to varying extents in these mutants. Arrest by ndt80 restored these events in two severe hypomorphic mutants, suggesting that ndt80-arrested nuclei are capable of extended DSB activity. While crossing-over, spore viability and synaptonemal complex (SC) formation defects correlated, the extent of such defects was not predictive of the level of heteroallelic gene conversions (prototrophs) exhibited by each mutant. High throughput sequencing of tetrads from spo11 hypomorphs revealed that gene conversion tracts associated with COs are significantly longer and gene conversion tracts unassociated with COs are significantly shorter than in wild type. By modeling the extent of these tract changes, we could account for the discrepancy in genetic measurements of prototrophy and crossover association. These findings provide an explanation for the unexpectedly low prototroph levels exhibited by spo11 hypomorphs and have important implications for genetic studies that assume an unbiased recovery of prototrophs, such as measurements of CO homeostasis. Our genetic and physical data support previous observations of DSB-limited meioses, in which COs are disproportionally maintained over NCOs (CO homeostasis).
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, United States of America.
authors.forename: Beth
authors.initials: B
authors.lastname: Rockmill
authors.forename: Philippe
authors.initials: P
authors.lastname: Lefrançois
authors.forename: Karen
authors.initials: K
authors.lastname: Voelkel-Meiman
authors.forename: Ashwini
authors.initials: A
authors.lastname: Oke
authors.forename: G Shirleen
authors.initials: GS
authors.lastname: Roeder
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: Fung
mesh_terms: D000483:Alleles; D023902:Chromosome Pairing / Q000235:genetics; D020090:Chromosome Segregation / Q000235:genetics*; D003434:Crossing Over, Genetic / Q000235:genetics; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair / Q000235:genetics; D004706:Endodeoxyribonucleases / Q000235:genetics* / Q000378:metabolism; D005785:Gene Conversion / Q000235:genetics; D059014:High-Throughput Nucleotide Sequencing; D006706:Homeostasis / Q000235:genetics; D008540:Meiosis / Q000235:genetics; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D013573:Synaptonemal Complex / Q000235:genetics*; D000099257:Meiotic Recombination Protein SPO11
chemical_list: D004706:Endodeoxyribonucleases; D029701:Saccharomyces cerevisiae Proteins; C518938:Spo11 protein, S cerevisiae; D000099257:Meiotic Recombination Protein SPO11