Open AccessMg2+ induces a sharp and reversible transition in U1 and U2 small nuclear ribonucleoprotein configurations.
Author(s) -
Isabelle Reveillaud,
Marie-Noëlle Lelay-Taha,
Joannés Sri-Widada,
Claude Brunel,
Philippe Jeanteur
Publication year - 1984
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.4.9.1890
Subject(s) - snrnp , small nuclear ribonucleoprotein , biology , ribonucleoprotein , small nuclear rna , rna splicing , nucleotide , micrococcal nuclease , sequence (biology) , rna , ribonuclease t1 , microbiology and biotechnology , biophysics , biochemistry , rnase p , dna , histone , gene , non coding rna , nucleosome
When U1 and U2 small nuclear ribonucleoproteins (snRNPs) purified by a procedure which preserves their immunoprecipitability by autoimmune antibodies (Hinterberger et al., J. Biol. Chem. 258:2604-2613, 1983), were submitted to extensive digestion with micrococcal nuclease, we found that their degradation pattern was sharply dependent upon magnesium concentration, indicating that they undergo a profound structural modification. At low Mg2+ (less than or equal to 5 mM), both particles only exhibit a core-resistant structure previously identified as being common to all but U6 snRNAs (Liautard et al., J. Mol. Biol. 162: 623-643, 1982). At high Mg2+ (greater than or equal to 7 mM), U1 and U2 snRNPs behave differently from one another. In U1 snRNP, most U1 snRNA sequence is protected, except for the 10 5'-terminal nucleotides presumably involved in splicing and a short sequence between nucleotides 102 and 108. Another region spanning nucleotides 60 to 79 is only weakly protected. This structural modification was demonstrated to be reversible. In U2 snRNP, the U2 snRNA sequence remains exposed in its 5' part up to nucleotide 92, and the 3'-terminal hairpin located outside the core structure becomes protected.