Ischemia induces a translocation of the splicing factor tra2-beta 1 and changes alternative splicing patterns in the brain.
Alternative splice-site selection is regulated by the relative concentration of individual members of the serine-arginine family of proteins and heterogeneous nuclear ribonucleoproteins. Most of these proteins accumulate predominantly in the nucleus, and a subset of them shuttles continuously between nucleus and cytosol. We demonstrate that in primary neuronal cultures, a rise in intracellular calcium concentration induced by thapsigargin leads to a translocation of the splicing regulatory protein tra2-beta1 and a consequent change in splice-site selection. To investigate this phenomenon under physiological conditions, we used an ischemia model. Ischemia induced in the brain causes a cytoplasmic accumulation and hyperphosphorylation of tra2-beta1. In addition, several of the proteins binding to tra2-beta1, such as src associated in mitosis 68 and serine/arginine-rich proteins, accumulate in the cytosol. Concomitant with this subcellular relocalization, we observed a change in alternative splice-site usage of the ICH-1 gene. The increased usage of its alternative exons is in agreement with previous studies demonstrating its repression by a high concentration of proteins with serine/arginine-rich domains. Our findings suggest that a change in the calcium concentration associated with ischemia is part of a signaling event, which changes pre-mRNA splicing pathways by causing relocalization of proteins that regulate splice-site selection.
Daoud
Rosette
R
Institute of Biochemistry, University of Erlangen-Nurenberg, 91054 Erlangen, Germany.
Mies
Günter
G
Smialowska
Agata
A
Oláh
Laszlo
L
Hossmann
Konstantin-Alexander
KA
Stamm
Stefan
S
D017398:Alternative Splicing / Q000502:physiology; D000818:Animals; D001921:Brain / Q000098:blood supply / Q000378:metabolism* / Q000473:pathology; D002545:Brain Ischemia / Q000378:metabolism* / Q000473:pathology; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D053143:Caspase 2; D020169:Caspases / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D004195:Disease Models, Animal; D029721:Drosophila Proteins; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D010766:Phosphorylation; D020033:Protein Isoforms / Q000378:metabolism; D021381:Protein Transport / Q000502:physiology; D012322:RNA Precursors / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism; D051381:Rats; D012261:Ribonucleoproteins / Q000378:metabolism*; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases
D029721:Drosophila Proteins; D004791:Enzyme Inhibitors; D009687:Nuclear Proteins; D020033:Protein Isoforms; D012322:RNA Precursors; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; C066174:tra2 protein, Drosophila; D053143:Caspase 2; D020169:Caspases; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D000252:Calcium-Transporting ATPases; D002118:Calcium