SELF-ASSOCIATION OF CHROME DOMAIN PEPTIDES

The chromo domain is a sequence motif first recognised in the Drosophi la polycomb protein and heterochromatin protein (HPI), two proteins as sociated with stable and heritable transcriptional silencing. Polycomb is one of a number of genes that are required to prevent ectopic home otic gene expression in Drosophila, while HP1, the product of the Dros ophila melanogaster Su(var)205 gene, is associated with the phenomenon of position effect variegation. These proteins are believed to be com ponents of chromatin-associated multi-protein complexes that bring abo ut stable transcriptional silencing and the chrome domain has been imp licated in chromatin targeting, probably through protein-protein inter action. Recently, mammalian homologues of both polycomb and HP1 have b een described. Here we demonstrate for the first time that oligopeptid es containing a chrome domain derived from the mouse polycomb homologu e M33 form multimeric complexes in solution, supporting the role of th e chrome domain in multiprotein complex assembly.