Regulation of alternative pre-mRNA splicing by the ERK MAP-kinase pathway
Susanne Weg-Remers1,2,
Helmut Ponta1,
Peter Herrlich1,3, and
Harald König1
1Forschungszentrum Karlsruhe der Helmholtz-Gemeinschaft, Institut für Toxikologie und Genetik and 3Universität Karlsruhe, Institut für Genetik, Postfach 3640, 76021 Karlsruhe, Germany 2Corresponding author e-mail: susanne.weg{at}itg.fzk.de
Abstract:
Differential gene expression through alternative pre-mRNA splicing is crucial to various physiological and pathological conditions. Upon activation of B and T lymphocytes during an immune response, variant isoforms of the cell surface molecule CD44 are generated by alternative pre-mRNA splicing. We show here that in primary mouse T cells as well as in the murine LB-17 T-cell line upregulation of variant CD44 mRNA species upon T-cell activation requires activation of the MEK–ERK pathway. By employing mutant signaling molecules and a novel luciferase-based splice reporter system we demonstrate that the Ras–Raf–MEK–ERK signaling cascade, but not the p38 MAP-kinase pathway, activates a mechanism that retains variant CD44 exon v5 sequence in mature mRNA. The findings demonstrate that a highly conserved pleiotropic signaling pathway links extracellular cues to splice regulation, providing an avenue for tissue-specific, developmental or pathology-associated splicing decisions.
Key Words: Keywords: alternative splicing/CD44/MAP kinase/signal transduction/T cells
