Condensin suppresses recombination and regulates double-strand break processing at the repetitive ribosomal DNA array to ensure proper chromosome segregation during meiosis in budding yeast.
Bottom Line: Condensin is highly enriched at the rDNA region during prophase I, released at the prophase I/metaphase I transition, and reassociates with rDNA before anaphase I onset.We show that condensin plays a dual role in maintaining rDNA stability: it suppresses the formation of Spo11-mediated rDNA breaks, and it promotes DSB processing to ensure proper chromosome segregation.Our work reveals that condensin coordinates meiotic recombination with chromosome segregation at the repetitive rDNA sequence, thereby maintaining genome integrity.
Affiliation: Department of Biological Science, Florida State University, Tallahassee, FL 32306-4370.Show MeSH
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Mentions: Condensin is highly enriched at the yeast rDNA gene cluster at the meiotic prophase I. It is released from the rDNA at the prophase I/metaphase I transition and then is reloaded at anaphase I during chromosome segregation. Release of rDNA-associated condensin is regulated by Cdc5, whereas reloading of condensin at anaphase I requires Cdc14 (Figure 8), which itself resides at the rDNA/nucleolus during much of the cell cycle (Shou et al., 1999; Visintin et al., 1999). Subunits of the monopolin complex are required for condensin recruitment to rDNA in proliferating yeast cells (Johzuka and Horiuchi, 2009) and Cdc5 is required for monopolin relocalization (Clyne et al., 2003), indicating that Cdc5 may indirectly regulate condensin release from rDNA during meiosis. Regulation of condensin relocalization by the kinase (Cdc5) and phosphatase (Cdc14) pair highlights the importance of posttranslational modification of condensin subunits.
Affiliation: Department of Biological Science, Florida State University, Tallahassee, FL 32306-4370.