The Triton X-100 and high salt resistant residue of Saccharomyces cerevisiae nuclear membranes.

Saccharomyces cerevisiae nuclear membranes were prepared from isolated nuclei by digesting chromatin with deoxyribonuclease after an initial treatment of nuclei with very diluted buffers. When the nuclear membranes were treated with 5% Triton X-100 and 1M NaCl an insoluble fibrous net was obtained which consisted mainly of protein with Mr values of 85 000, 48 000, 45 000, 39 000 and 31 000. Lamins, a set of proteins with Mr = 65 000--75 000, which were shown to be the major proteins of the insoluble nuclear membrane residue of higher eukaryotes, were not found.