Meiotic recombination normally takes place between allelic sequences on homologs. This process can also occur between non-allelic homologous sequences. Such ectopic interaction events can lead to chromosome rearrangements and must be avoided. However, much remains unknown about how these ectopic interaction events are sensed and eliminated.

 

In a recent study, researchers in CHENG Zhukuan’s Group characterized a homolog of HUS1 and explored its function in meiotic recombination. They found that vigorous and aberrant ectopic interactions occurred between nonhomologous chromosomes in Oshus1 mutants, leading to multivalent formation and subsequent chromosome fragmentation. These ectopic interactions relied on programed meiotic double strand breaks. Although early homologous recombination events occurred normally, the number of interference-sensitive crossovers was reduced in the absence of OsHUS1.

 

These facts suggested that OsHUS1 might be involved in regulating ectopic interactions during meiosis, probably by forming the canonical RAD9-RAD1-HUS1 (9-1-1) complex.

 

This work has been published on PLoS Genetics (DOI: 10.1371/journal.pgen. 1004405). This research was supported by Ministry of Science and Technology of China, and National Natural Science Foundation of China.