Cover photograph (Copyright © 2007, American Society for Microbiology. All Rights Reserved.): H2A.Z is excluded from pericentric heterochromatin in differentiated mouse fibroblasts. Mouse 10T1/2 fibroblasts were stained using an antibody against H2A.Z (red) and HP1a (green) and examined by immunofluorescence microscopy. The H2A.Z antibody shows punctate nuclear staining, which is excluded from the HP1a-enriched pericentric heterochromatin. (See related article on September 2006, vol. 27: issue 18, p. 6457.)