REGULATION OF GENE-EXPRESSION BY NUCLEOSOMES

During the past year, the characterization of mechanisms and factors c apable of disrupting nucleosomes during transcriptional activation has been a recurrent theme in studies which address the contribution of n ucleosome structure to gene regulation. In vivo studies using yeast an d Drosophila together with biochemical purification schemes using nucl eosome perturbation assays have provided evidence for the existence of multiprotein complexes that are able to alleviate nucleosome repressi on. At the same time, new insights into the mechanism of heterochromat in formation have been gained, which have direct links to nucleosome s tructure.