A short chromosomal region with major roles in yeast chromosome III meiotic disjunction, recombination and double strand breaks.
A multicopy plasmid was isolated from a yeast genomic library, whose presence resulted in a twofold increase in meiotic nondisjunction of chromosome III. The plasmid contains a 7.5-kb insert from the middle of the right arm of chromosome III, including the gene THR4. Using chromosomal fragments derived from chromosome III, we determined that the cloned region caused a significant, specific, cis-acting increase in chromosome III nondisjunction in the first meiotic division. The plasmid containing this segment exhibited high spontaneous meiotic integration into chromosome III (in 2.4% of the normal meiotic divisions) and a sixfold increase (15.5%) in integration in nondisjunctant meioses. Genetic analysis of the cloned region revealed that it contains a "hot spot" for meiotic recombination. In DNA of rad50S mutant cells, a strong meiosis-induced double strand break (DSB) signal was detected in this region. We discuss the possible relationships between meiosis-induced DSBs, recombination and chromosome disjunction, and propose that recombinational hot spots may be "pairing sites" for homologous chromosomes in meiosis.
Goldway
M
M
Department of Genetics, Hebrew University of Jerusalem, Israel.
Sherman
A
A
Zenvirth
D
D
Arbel
T
T
Simchen
G
G
D015825:Chromosomes, Fungal; D004249:DNA Damage; D004274:DNA, Recombinant; D005819:Genetic Markers; D005822:Genetic Vectors; D008540:Meiosis; D009630:Nondisjunction, Genetic; D010957:Plasmids; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics*
D004274:DNA, Recombinant; D005819:Genetic Markers