On the cover: Immunocytochemical staining of a wild-type (WT) cardiac side population (cSP) cell in mitosis. The middle panel illustrates a WT cSP cell expressing Abcg2 (red) in the cytosol and phospho-histone H₃ (green) in the nucleus (blue). The surrounding panels demonstrate the chromosomes stained with DAPI, as well as the presence of phospho-histone H₃ in the individual z-stack sections of the nucleus. See related article, page 825.