Open AccessSite-specific cleavage by T1 RNase of U-1 RNA in u-1 ribonucleoprotein particles.
Author(s) -
Paul N. Epstein,
Ram Reddy,
Harris Busch
Publication year - 1981
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.78.3.1562
Subject(s) - rnase p , rna , ribonucleoprotein , cleavage (geology) , microbiology and biotechnology , rnase h , ribonucleoprotein particle , heterogeneous nuclear ribonucleoprotein , nuclease protection assay , chemistry , biology , rna dependent rna polymerase , biochemistry , gene , paleontology , fracture (geology)
The structures and functions of small nuclear ribonucleoprotein particles have become of interest because of their suggested role in processing heterogeneous nuclear RNA [Lerner, M. R., Boyle, J. A., Mount, S. M., Wolin S. L. & Steitz, J. A. (1980) Nature (London) 283, 220-224]. To determine the conformation of U-1 RNA in U-1 ribonucleoprotein particles and whether proteins of these particles protect segments of U-1 RNA, intact particles and isolated U-1 RNA were digested with T1 RNase. The digested particles were immunoprecipitated with anti-Sm antibodies. A 5'-end fragment containing nucleotides 1-107 and 3'-end fragments containing nucleotides 108-165 and 108-153 were recovered in nearly quantitative yield from digestion of the particles, suggesting that position 107 is the principal cleavage site in them. At the same T1 RNase concentrations, deproteinized U-1 RNA was cleaved into many fragments. At low T1 RNase concentrations, major cleavage site of deproteinized U-1 RNA was at nucleotide 69. Comparison of the cleavage sites of free U-1 RNA and of U-1 RNA in U-1 ribonucleoprotein particles suggested similar secondary structures. The resistance of the 5' end of U-1 RNA to T1 RNase was unexpected inasmuch as this region has been implicated in hydrogen bonding with heterogeneous nuclear RNA splice junctions.