Required for the pachytene checkpoint, the meiotic checkpoint that prevents chromosome segregation when defects in recombination and synaptonemal complex formation occurred. Represses meiotic recombination in the rDNA, probably by excluding the meiosis-specific protein HOP1 from the nucleolar region. The majority of the protein localizes to the nucleolar region containing the ribosomal RNA genes (rDNA), a tandem array of 100-150 repeats on chromosome XII. Localization is SIR2-dependent. Induced at the onset of meiosis I and reaches a maximum level during pachytene (at protein level). Belongs to the AAA ATPase family. PCH2 subfamily.