InterPro domain: IPR034546

The representative of this plant family is PAIR1 (HOMOLOGOUS PAIRING ABERRATION IN RICE MEIOSIS1), a protein that plays an essential role in establishment of homologous chromosome pairing in meiosis. Mutations in the gene encoding this protein also affect spindle formation and sporulation [ 1 ]. This family also contains the Putative recombination initiation defects 3 (AtPRD3) involved in the meiotic recombination initiation [ 2 ].

In flowering plants, gametophyte formation relies on meiosis. In meiosis I, the homologous chromosomes are separated into two daughter cells. In meiosis II, the sister chromosomes are then separated into newly formed daughter cells. During prophase I, several events occurs: sister chromatid cohesion, homologous chromosome synapsis, recombination, crossover formation and chromosome segregation. Homologous recombination is initiated from the formation of DNA double-strand breaks (DSBs). The formation of DSBs is catalyzed by Spo11 and its homologues. So far, six Arabidopsis proteins, AtSPO11-1, AtSPO11-2, AtPRD1, AtPRD2, AtPRD3 and AtDFO, have been shown to be involved in DSB formation [ 3 ].

1. The novel gene HOMOLOGOUS PAIRING ABERRATION IN RICE MEIOSIS1 of rice encodes a putative coiled-coil protein required for homologous chromosome pairing in meiosis. Plant Cell 16, 1008-20
2. A high throughput genetic screen identifies new early meiotic recombination functions in Arabidopsis thaliana. PLoS Genet. 5, e1000654
3. MTOPVIB interacts with AtPRD1 and plays important roles in formation of meiotic DNA double-strand breaks in Arabidopsis. Sci Rep 7, 10007