a, schematic for nuclear transfer into prometaphase and b, corresponding images. Nuclei of fibroblasts at interphase are transferred into a zygote at prometaphase of mitosis. Chromosomes are marked with the red fluorescent fusion protein H2B-cherry. Shown is the mitotic progression after nuclear transfer. Time indicates the hours after nuclear transfer. Note the condensation of chromosomes and their separation into two groups, followed by formation of 2 pronuclei after inhibition of cytokinesis and entry into interphase. c, removal of the genome from a zygote at anaphase. d, Nuclear morphology after transfer of interphase nuclei. Small inset: a somatic donor cell before transfer. Note that somatic donor chromatin is not condensed. e, nuclear remodeling is slow and requires about 1 day to restructure the nucleus into a large blastomere-like morphology. f, cluster analysis of gene expression after mouse SCNT. g, Venn diagram of transcripts elevated 22-24h after nuclear transfer at anaphase. h, development to morula and blastocyst stage (as % of transferred). Size bar 10μm.