Decrease in hnRNP A/B expression during erythropoiesis mediates a pre-mRNA splicing switch
A physiologically important alternative pre-mRNA splicing switch, involving activation of protein 4.1R exon 16 (E16) splicing, is required for establishing proper mechanical integrity of the erythrocyte membrane during erythropoiesis. Here we identify a conserved exonic splicing silencer element (CE16) in E16 that interacts with hnRNP A/B proteins and plays a role in repression of E16 splicing during early erythropoiesis. Experiments with model pre-mRNAs showed that CE16 can repress splicing of upstream introns, and that mutagenesis or replacement of CE16 can relieve this inhibition. An affinity selection assay with biotinylated CE16 RNA demonstrated specific binding of hnRNP A/B proteins. Depletion of hnRNP A/B proteins from nuclear extract significantly increased E16 inclusion, while repletion with recombinant hnRNP A/B restored E16 silencing. Most importantly, differentiating mouse erythroblasts exhibited a stage-specific activation of the E16 splicing switch in concert with a drama tic and specific down-regulation of hnRNP A/B protein expression. These findings demonstrate that natural developmental changes in hnRNP A/B proteins can effect physiologically important switches in pre-mRNA splicing.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director, Office of Science; National Institutes of Health (NIH); Merit Review Award from the Dept of Veterans Affairs (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 806131
- Report Number(s):
- LBNL-51667; R&D Project: 863E1C; B& R 400412000; TRN: US200303%%564
- Journal Information:
- The EMBO Journal (European Molecular Biology Organization), Vol. 21, Issue 22; Other Information: Journal Publication Date: Nov. 15, 2002; PBD: 17 Oct 2002
- Country of Publication:
- United States
- Language:
- English
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