Messenger RNA reprogramming by spliceosome-mediated RNA trans-splicing
Mariano A. Garcia-Blanco
Mariano A. Garcia-Blanco
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Messenger RNA reprogramming by spliceosome-mediated RNA trans-splicing

Abstract

In the human genome, the majority of protein-encoding genes are interrupted by introns, which are removed from primary transcripts by a macromolecular enzyme known as the spliceosome. Spliceosomes can constitutively remove all the introns in a primary transcript to yield a fully spliced mRNA or alternatively splice primary transcripts leading to the production of many different mRNAs from one gene. This review examines how spliceosomes can recombine two primary transcripts in trans to reprogram messenger RNAs.

Authors

Mariano A. Garcia-Blanco

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Figure 1

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The structure of human genes and primary transcripts. A schematic of a g...
The structure of human genes and primary transcripts. A schematic of a gene (DNA), its primary transcript (pre-mRNA), and the mature mRNA product. The gene in this schematic spans four exons (boxes 1 through 4) and three introns. Genomic landmarks are indicated for the middle intron: the 5′ splice site (5′ ss), the branchpoint (BP) adenosine, the polypyrimidine tract (Py), and the 3′ splice site (3′ ss). The structure of the pre-mRNA, which is synthesized by RNA polymerase II, is shown. The 5′ end of the pre-mRNA is determined by transcription initiation and modified by a cap structure (27). The 3′ end is created and modified by cleavage and polyadenylation (poly A). Introns are removed in pre-mRNA splicing to yield an mRNA. On average, introns are longer than 3,000 nucleotides. The 5′ and 3′ terminal exons (1 and 4) average 300 nucleotides in length; internal exons (2 and 3) average 145 nucleotides in length (14, 15).