PROTECTED NUCLEOTIDE-SEQUENCES IN NUCLEAR RIBONUCLEOPROTEIN

The rapidly labeled nuclear ribonucleic acid in human carcinoma cells which is protected by protein from digestion by staphylococcal nuclease (EC 3.1.4.7) has been investigated. A simple and discrete sequence specificity was not found, but the protected RNA fragments are rich in G + C and were shown by fingerprinting to comprise a non-random subset of all heterogeneous nuclear ribonucleic acid (hnRNA) sequences enriched in the sequences AGC, GGC, AGGC, and GAGC. There was no detectable enrichment for double-stranded RNA in the protected fraction. These data provide the first evidence that the association of any protein with hnRNA is nonrandom with respect to nucleotide sequence. © 1979, American Chemical Society. All rights reserved.