Analysis of AtMND1 in Arabidopsis thaliana

Meiosis is the specialised cell division of sexually reproducing organisms in which the chromosome number is reduced by half during gamete formation. During the process of meiosis, maternal and paternal chromosomes are replicated, recombined and subsequently distributed to four daughter cells in two successive rounds of cell division. Defects during the process of meiotic division lead to gametes with an aberrant DNA content, cell death and sterility. Mnd1 is an important meiotic protein involved in the exchange of genetic material during homologous recombination of chromosomes. Inactivation of Mnd1 in S. cerevisae prevents homologous recombination. Preliminary data, presented in this grant proposal, demonstrate the importance of Mnd1 in plants, since mutation of the corresponding gene, AtMND1, leads to sterility. This project focuses on the characterisation of the meiotic protein, AtMnd1, in the model plant Arabidopsis thaliana. A. thaliana offers advantages over other model organisms in the study of meiosis, since it is amenable to molecular, cytological and genetic analysis, and all stages of meiosis can be studied, since mutations affecting meiotic genes do not trigger a cell cycle check point, in contrast to yeast and mammals. Furthermore, it emerges that simple model organisms such as S. cerevisae do not reflect the full complexity of interactions of proteins in higher eukaryotes. Therefore, to fully understand the function of a meiotic protein such as Mnd1, and to reveal its interplay with other, potentially unknown protein factors, Mnd1 must be characterised in different species. The work outlined in this grant addresses the following questions: (1) What defect underlies the sterility phenotype observed in atmnd1 mutant plants? (2) When does AtMnd1 act during meiosis? (3) Where is AtMnd1 located and does its localisation depend on other proteins? (4) Which proteins interact with AtMnd1? The experiments outlined in this project represent the first attempt to characterise Mnd1 in plants, and will contribute to the understanding of its function and meiosis in general.

Meiosis is the specialised cell division of sexually reproducing organisms in which the chromosome number is reduced by half during gamete formation. During the process of meiosis, maternal and paternal chromosomes are replicated, recombined and subsequently distributed to four daughter cells in two successive rounds of cell division. Defects during the process of meiotic division lead to gametes with an aberrant DNA content, cell death and sterility. Mnd1 is an important meiotic protein involved in the exchange of genetic material during homologous recombination of chromosomes. Inactivation of Mnd1 in S. cerevisae prevents homologous recombination. Preliminary data, presented in this grant proposal, demonstrate the importance of Mnd1 in plants, since mutation of the corresponding gene, AtMND1, leads to sterility. This project focuses on the characterisation of the meiotic protein, AtMnd1, in the model plant Arabidopsis thaliana. A. thaliana offers advantages over other model organisms in the study of meiosis, since it is amenable to molecular, cytological and genetic analysis, and all stages of meiosis can be studied, since mutations affecting meiotic genes do not trigger a cell cycle check point, in contrast to yeast and mammals. Furthermore, it emerges that simple model organisms such as S. cerevisae do not reflect the full complexity of interactions of proteins in higher eukaryotes. Therefore, to fully understand the function of a meiotic protein such as Mnd1, and to reveal its interplay with other, potentially unknown protein factors, Mnd1 must be characterised in different species. The work outlined in this grant addresses the following questions: 1. What defect underlies the sterility phenotype observed in atmnd1 mutant plants? 2. When does AtMnd1 act during meiosis? 3. Where is AtMnd1 located and does its localisation depend on other proteins? 4. Which proteins interact with AtMnd1? The experiments outlined in this project represent the first attempt to characterise Mnd1 in plants, and will contribute to the understanding of its function and meiosis in general.