Control of alternative pre-mRNA splicing by distributed pentameric repeats.
Multiple copies of the hexamer TGCATG have been shown to regulate fibronectin pre-mRNA alternative splicing. GCATG repeats also are clustered near the regulated calcitonin-specific 3' splice site in the rat calcitonin/CGRP gene. Specific mutagenesis of these repeats in calcitonin/CGRP pre-mRNA resulted in the loss of calcitonin-specific splicing, suggesting that the native repeats act to enhance alternative exon inclusion. Mutation of subsets of these elements implies that alternative splicing requires a minimum of two repeats, and that the combination of one intronic and one exonic repeat is necessary for optimal cell-specific splicing. However, multimerized intronic repeats inhibited calcitonin-specific splicing in both the wild-type context and in a transcript lacking endogenous repeats. These results suggest that both the number and distribution of repeats may be important features for the regulation of tissue-specific alternative splicing. Further, RNA containing a single repeat bound cell-specific protein complexes, but tissue-specific differences in protein binding were not detected by using multimerized repeats. Together, these data support a novel model for alternative splicing regulation that requires the cell-specific recognition of multiple, distributed sequence elements.
Hedjran
F
F
Howard Hughes Medical Institute and Department of Medicine, School of Medicine, University of California at San Diego, La Jolla, CA 92093-0648, USA.
Yeakley
J M
JM
Huh
G S
GS
Hynes
R O
RO
Rosenfeld
M G
MG
D017398:Alternative Splicing; D000818:Animals; D002116:Calcitonin / Q000096:biosynthesis / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D012322:RNA Precursors / Q000235:genetics*; D051381:Rats; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*
D012322:RNA Precursors; D002116:Calcitonin