期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1977
卷号：74
期号：12
页码：5492-5495
DOI：10.1073/pnas.74.12.5492
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Two-dimensional gel profiles of the 0.2 M H2SO4-soluble proteins of monomer nucleosomal fractions were found to contain protein A24. Protein A24 is of interest because it is composed of histone 2A and "ubiquitin", apparently joined by an isopeptide linkage [Goldknopf, I.L. & Busch, H. (1977) Proc. Natl. Acad. Sci. USA 74, 864-868; Hunt, L.T. & Dayhoff, M.O. (1977) Biochem. Biophys. Res. Commun. 74, 650-655]. Monomer nucleosomal fractions were obtained by sucrose density gradient centrifugation of micrococcal nuclease digests of rat liver nuclei. As shown by their DNA size, the monomer fractions were highly purified. Proteins A24 and Bu, another protein of unknown characteristics, were found along with histones 1, 2A, 2B, 3, and 4 in the monomer fractions in relative amounts similar to those found in extracts from whole nuclei and chromatin. Other acid-soluble proteins found in the nuclear and chromatin extracts were essentially absent from the monomer fraction. Inasmuch as protein A24 and Bu were found in lesser amounts than the histones, it is suggested that they are associated with specialized subsets of nucleosomes.
