The winning image of this month's Nature Cell Biology and Nature Reviews Molecular Cell Biology 'Cell of the Month' competition was submitted by David Solomon (Department of Cell Biology, University of Cincinnati College of Medicine, USA (david.solomon@uc.edu)). It shows heterochromatic domains in the nucleus of a mouse adult fibroblast.

The dimethylated lysine 9 of histone H3 is shown in green, the Swi/Snf core ATPase Brg1 in red, and DNA in blue. The image was obtained using a Nikon Microphot FX fluorescence microscope. Bar, 3 μm.

The winner would like to acknowledge the support of his advisor, Erik Knudsen, and technical assistance from Nancy Kleene (both at the University of Cincinnati College of Medicine, USA).