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：1981
卷号：78
期号：4
页码：2208-2212
DOI：10.1073/pnas.78.4.2208
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Contacts between heterogeneous nuclear RNA (hnRNA) and protein in nuclear ribonucleoprotein particles have been photochemically crosslinked in intact HeLa or Friend erythroleukemia cell by irradiation with 254-nm light at doses of 10(1) to 10(5) ergs/mm2 (1 to 10(4) microJ/mm2). The resulting crosslinked particles were isolated and compared with conventional hnRNA . protein (hnRNP) preparations. By the criteria of nuclear fractionation behavior, sedimentation coefficients, nuclease digestion profiles, and RNA-to-protein ratio measured by banding in Cs2SO4 density gradients, the hnRNP particles crosslinked in vivo are identical to nonirradiated particles. Gel blot hybridization of RNA from Friend cell hnRNP crosslinked in vivo reveals that beta-globin RNA sequences remain both intact and hybridizable after the irradiation procedure. The crosslinked hnRNA--protein bonds are stable in 8 M urea/0.5% sodium dodecyl sulfate and withstand centrifugation in Cs2SO4 gradients of initial density 1.50 g/cm3. These results establish that hnRNA is tightly complexed with nuclear proteins in vivo and that hnRNP particles isolated by nuclear fractionation represent native structures.
