Calendar Name: seminars Scheduled for: Thursday, November 17 2011, 11:00 - 12:30 Event text: Prof Reidunn Birgitta Aalen Department of Molecular Biosciences University of Oslo NORWAY Details: "Matching ligands with receptors and readers with writers of the histone code" ABSTRACT Multicellular organisms are dependent on mechanisms of cell-to-cell communication and tight control of gene expression to ensure that each cell attains the correct function in the organism as a whole. My group is elucidating these mechanism by two approaches � our aim is 1) to match putative peptide ligands with receptors, and 2) to understand how histone lysine methyltransferases (HKMTases) influence chromatin structure: 1) Although there are about thousand genes in Arabidopsis encoding putative secreted peptide ligands, and more than four hundred encoding receptor-like kinases (RLKs), less than a dozen peptide ligands � receptor pairs influencing development have been identified to date (Butenko et al, Trends Plant Sci, 2009). One of these modules is the INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) peptide signaling through the leucine-rich repeat (LRR) RLKs HAESA and HAESA-LIKE 2 to control floral organ abscission after pollination has taken place (Stenvik et al, Plant Cell, 2008; Shi et al, Plant Cell, 2011). We have suggested that IDA as well as IDA-LIKE peptides, which share a conserved proline-rich C-terminal motif, signal through HAESA-LIKE LRR-RLKs also to control other cell separation processes in plants. 2) Ten years ago we identified the near to forty Arabidopsis genes encoding SET-domain proteins, which are putative HKMTases (Baumbusch et al, Nucl Acids Res, 2001; Thorstensen et al, BBA, 2011). Recently we have demonstrated the importance of co-domains in such proteins � the WIYLD domain of the H3K9me2/me3 HKMTase SUVR4 is a ubiquitin-binding domain that can regulate the product specificity of SUVR4 in relation to its suppression of transposon activity (Thorstensen et al, PLoS Genetics, 2011); and the CW domain of the H3K36me2/me3 HKMTase ASHH2 is a novel reader of H3K4me assisting in ASHH2�s global involvement in maintenance of tissue-specific gene expression (Hoppmann et al. EMBO J, 2011).