The Saccharomyces cerevisiae gene ECM11 is a positive effector of meiosis.

Ecm11 is classified as a protein involved in yeast cell wall biogenesis and organization, but in this paper, we provide evidence that it is involved in meiosis as well. Mutants with deleted ECM11 exhibit complex defects in meiosis: replication, recombination and chromosome segregation are affected. The ecm11Delta diploid strains sporulate more slowly and less efficiently than parental strains with wild type copies of ECM11. Fluorescence activated cell sorter scans of DNA content during sporulation showed that meiotic DNA synthesis is initiated at the same time in parental and ecm11Delta strains, but is less efficient in the knockout strain. By recombination tests, we demonstrated that ECM11 is required for crossing-over, but not for gene conversion. In the absence of ECM11 gene product, viability of spores is reduced to 50% and predominantly two viable spores per tetrad are formed. Our results suggest that ECM11 is required in early stages of meiosis where its function is related to DNA replication and crossing-over.