| Autor: |
Walker, John M., Haynes, Susan R., Ruby, Stephanie W. |
| Zdroj: |
RNA-Protein Interaction Protocols; 1999, p323-349, 27p |
| Abstrakt: |
Splicing of eukaryotic precursor messenger RNAs (pre-mRNAs) excises the intron from the precursor and ligates the two exons together to produce the mature mRNA. It occurs via a two-step mechanism (Fig. 1) (reviewed in ref. 1). In the first step the 2′ hydroxyl group of an intronic adenylyl residue initiates a transesterfication reaction at the 5′ splice site. The result is the cleavage of the 5′ splice site phosphodiester bond and the formation of a new, 2′-5′ phosphodiester bond between the adenylyl residue and the 5′ end of the intron. Because the intronic adenylyl residue has both 2′-5′ and 3′-5′ phosphodiester bonds, it is commonly referred to as the branch point nucleotide. The first splicing step yields two intermediates, "free" exon 1 and the lariat intermediate, which are not covalently linked together. In the second step, the 3′ hydroxyl of the "free" exon 1 initiates a second transesterification reaction at the 3′ splice site, resulting in the ligation of the two exons together to form the mRNA and the release of the lariat intron. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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