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trans splicing of polycistronic Caenorha ... e-mRNAs analysis of the SL2 RNA
trans splicing of polycistronic Caenorhabditis elegans pre-mRNAs: analysis of the SL2 RNA.
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Genes in Caenorhabditis elegans operons are transcribed as polycistronic pre-mRNAs in which downstream gene products are trans spliced to a specialized spliced leader, SL2. SL2 is donated by a 110-nucleotide RNA, SL2 RNA, present in the cell as an Sm-bound snRNP. SL2 RNA can be conceptually folded into a phylogenetically conserved three-stem-loop secondary structure. Here we report an in vivo mutational analysis of the SL2 RNA. Some sequences can be changed without consequence, while other changes result in a substantial loss of trans splicing. Interestingly, the spliced leader itself can be dramatically altered, such that the first stem-loop cannot form, with only a relatively small loss in trans-splicing efficiency. However, the primary sequence of stem II is crucial for SL2 trans splicing. Similarly, the conserved primary sequence of the third stem-loop plays a key role in trans splicing. While mutations in stem-loop III allow snRNP formation, a single nucleotide substitution in the loop prevents trans splicing. In contrast, the analogous region of SL1 RNA is not highly conserved, and its mutation does not abrogate function. Thus, stem-loop III appears to confer a specific function to SL2 RNA. Finally, an upstream sequence, previously predicted to be a proximal sequence element, is shown to be required for SL2 RNA expression.
Evans D, Blumenthal T
Molecular and cellular biology
2000-09-01 00:00
20
18
6659-67
Animals,Base Sequence,Caenorhabditis elegans,Gene Expression,Genes, Helminth,Molecular Sequence Data,Mutagenesis,Nucleic Acid Conformation,RNA Precursors,RNA, Helminth,RNA, Spliced Leader,Structure-Activity Relationship,Trans-Splicing,Transcription, Genetic,RNA Precursors,RNA, Helminth,RNA, Spliced Leader
Department of Biochemistry and Molecular Genetics, University of Colorado Health Sciences Center, Denver 80262, USA
Mol. Cell. Biol.
NIGMS GM42432
0270-7306
84
True
10958663
