Japan - Explore possibilities for research collaboration between Norway and Japan on endoreduplication in plants

Endereduplication is the process where the cell replicates chromosomal DNA without intervening mitoses. The result is a cell with increased number of nuclei and increased size in most cases. The process is well known in animal cells, for example in musc le cells where endoreduplication causes the muscles to increase considerably in size and make them more robust with an increased number of nuclei. Endoreduplication is less described in plants. Plant cell volumes also increase dramatically when cells unde rgo endoreduplication. Research in Hvoslef-Eide?s group in Norway has revealed that endereduplication may be involved in the developmentally important process of abscission in the model plant poinsettia. There are at present obtained 30 interesting clo nes containing gene sequences related to flower abscission in poinsettia. Six of these are homologous to known genes. One example is immunophilin, thought to be involved in endoreduplication. Keiko Sugimoto Shirasu?s research aims at understanding how pl ant cells determine their final cell size. One cellular strategy to allow a large increase in cell size is to amplify chromosomal DNA to increase the ploidy level within a cell, for example, through endoreduplication. Using Arabidopsis as a model system, the research addresses how plant cells endoreduplicate and how an increase in the ploidy level leads to an increase in cell size. The project aims at submitting a joint proposal to the Norwegian Functional Genetics (FUGE) Programme in 2006 and an equival ent Japanese programme. There will be a seminar in both Norway and Japan to increase the knowledge about eachothers research strengths and possibilities and how to complement one another and benefit from the two model systems.