U2 small nuclear RNP assembly in vitro.
AUTOR(ES)
Kleinschmidt, A M
RESUMO
Incubation of a SP6-transcribed human U2 RNA precursor molecule in a HeLa cell S100 fraction resulted in the formation of ribonucleoprotein complexes. In the presence of ATP, the particles that assembled had several properties of native U2 snRNP, including resistance to dissociation in Cs2SO4 gradients, their buoyant density, and pattern of digestion by micrococcal nuclease. These particles also reacted with Sm monoclonal antibody and a human autoantibody with specificity for the U2 snRNP-specific proteins A' and B", but not with antibodies for U1 snRNP-specific proteins. In contrast, the particles that formed in the absence of ATP did not have these properties. ATP analogs with non-hydrolyzable beta-gamma bonds did not substitute for ATP in U2 snRNP assembly. Additional experiments with a mutant U2 RNA confirmed that nucleotides 154-167 of U2 RNA are required for binding of the U2 snRNP-specific proteins but not of the "Sm" core proteins. Pseudouridine formation, a major post-transcriptional modification of U2 RNA, was enhanced under assembly permissive conditions.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=318034Documentos Relacionados
- Recognition of U1 and U2 small nuclear RNAs can be altered by a 5-amino-acid segment in the U2 small nuclear ribonucleoprotein particle (snRNP) B" protein and through interactions with U2 snRNP-A' protein.
- Leucine periodicity of U2 small nuclear ribonucleoprotein particle (snRNP) A' protein is implicated in snRNP assembly via protein-protein interactions.
- Mutations in an essential U2 small nuclear RNA structure cause cold-sensitive U2 small nuclear ribonucleoprotein function by favoring competing alternative U2 RNA structures.
- Pseudouridine formation in U2 small nuclear RNA.
- Small nuclear ribonucleoprotein (RNP) U2 contains numerous additional proteins and has a bipartite RNP structure under splicing conditions.