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Decrease in hnRNP A/B expression during erythropoiesis mediates a pre‐mRNA splicing switch
Author(s) -
Hou Victor C,
Lersch Robert,
Gee Sherry L.,
Ponthier Julie L.,
Lo Annie J.,
Wu Michael,
Turck Chris W.,
Koury Mark,
Krainer Adrian R.,
Mayeda Akila,
Conboy John G.
Publication year - 2002
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdf625
Subject(s) - national laboratory , library science , environmental ethics , art history , biology , history , philosophy , computer science , engineering , engineering physics
A physiologically important alternative pre‐mRNA splicing switch, involving activation of protein 4.1R exon 16 (E16) splicing, is required for the establishment of proper mechanical integrity of the erythrocyte membrane during erythropoiesis. Here we identify a conserved exonic splicing silencer element (CE 16 ) 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 CE 16 can repress splicing of upstream introns, and that mutagenesis or replacement of CE 16 can relieve this inhibition. An affinity selection assay with biotinylated CE 16 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 dramatic 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.