A cell-free system derived from carrot cell cytosol extract has been developed for reassembling nuclear structure around the added demembranated sperm chromatin of Xenopus. Morphological evidence suggests that reassembled nuclei display the typical characteristics of normal eukaryotic nuclei, such as double-layered nuclear membrane and nuclear pores. Micrococcal nuclease treatment indicates that remodeling of the demembranated sperm chromatin has occurred and the structure of nucleosome is formed during nuclear reconstitution. These data indicate that the nuclear reconstitution can be induced in cell-free systems from plants, and the self-assembly of the nucleus is ubiquitous in both animal and plant cells.