Splicing factor Prp8 governs U4/U6 RNA unwinding during activation of the spliceosome
| Autor: | David A. Brow, Andreas N. Kuhn, Zairong Li |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Spliceosome
Saccharomyces cerevisiae Proteins Ribonucleoprotein U4-U6 Small Nuclear RNA Splicing Molecular Sequence Data Exonic splicing enhancer Saccharomyces cerevisiae Biology Ribonucleoprotein U1 Small Nuclear Fungal Proteins Adenosine Triphosphate Suppression Genetic Protein splicing RNA Small Nuclear U4 spliceosomal RNA RNA Precursors Amino Acid Sequence Molecular Biology Ribonucleoprotein U5 Small Nuclear Genetics Intron Temperature RNA Fungal Cell Biology Cell biology Phenotype U6 spliceosomal RNA RNA splicing Mutation Spliceosomes Nucleic Acid Conformation RNA Sequence Alignment Small nuclear RNA |
| Zdroj: | Molecular cell. 3(1) |
| ISSN: | 1097-2765 |
| Popis: | The pre-mRNA 5′ splice site is recognized by the ACAGA box of U6 spliceosomal RNA prior to catalysis of splicing. We previously identified a mutant U4 spliceosomal RNA, U4-cs1, that masks the ACAGA box in the U4/U6 complex, thus conferring a cold-sensitive splicing phenotype in vivo. Here, we show that U4-cs1 blocks in vitro splicing in a temperature-dependent, reversible manner. Analysis of splicing complexes that accumulate at low temperature shows that U4-cs1 prevents U4/U6 unwinding, an essential step in spliceosome activation. A novel mutation in the evolutionarily conserved U5 snRNP protein Prp8 suppresses the U4-cs1 growth defect. We propose that wild-type Prp8 triggers unwinding of U4 and U6 RNAs only after structurally correct recognition of the 5′ splice site by the U6 ACAGA box and that the mutation ( prp8–201 ) relaxes control of unwinding. |
| Databáze: | OpenAIRE |
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