Sexually reproducing species rely on the exchange of genetic information between homologous chromosomes in a process referred to as meiosis. This can be summarised as one round of DNA replication accompanied by two rounds of chromosome segregation to produce haploid gametes from diploid cells. This process involves tight coordination of a meiotic specific cohesion complex, the synaptonemal complex and DNA damage repair mechanisms. We have investigated an uncharacterised protein, F28D1.2, which we have named
atz-1 (Abnormal Transition Zone) as a novel gene that is required for maintaining germline chromosome integrity. Deletion of
atz-1 results in reduced brood size and marked embryonic lethality. Interestingly,
atz-1 mutants display a depleted, or absent transition zone, accompanied by reduced expression of the meiotic cohesion protein, REC-8.
atz-1 mutants display downstream germline defects including disorganised and aggregated chromosomal bodies in diakinetic oocytes and elevated germ cell apoptosis. In addition to this,
atz-1 mutants are hypersensitive to mild inhibition of DNA damage repair by hydroxyurea, suggesting that the initial round of DNA replication in
atz-1 mutants is impaired. Moreover, the
atz-1 mutant phenotype is germline specific and resupplying somatically expressed
atz-1 does not rescue the reproductive defects associated with
atz-1 mutants. Overall, our data suggests that
atz-1 is required for promoting meiosis to maintain germline chromosomal integrity.