Peptide elongation factor eEF1A-2/S1 expression in cultured differentiated myotubes and its protective effect against caspase-3-mediated apoptosis.
Peptide elongation factor eEF1A-2/S1, which shares 92% homology with eEF1A-1/EF-1alpha, is exclusively expressed in brain, heart, and skeletal muscle. In these tissues, eEF1A-2/S1 is the only type 1A elongation factor expressed in adulthood because a transition from eEF1A-1/EF-1alpha to eEF1A-2/S1 occurs in early postnatal development. In this article, we report that the expression of eEF1A-2/S1 protein is activated upon myogenic differentiation. Furthermore, we show that upon serum deprivation-induced apoptosis, eEF1A-2/S1 protein disappears and is replaced by its homolog eEF1A-1/EF-1alpha in dying myotubes; cell death is characterized by the activation of caspase-3. In addition, we show that the continuous expression of eEF1A-2/S1 resulting from adenoviral gene transfer protects differentiated myotubes from apoptosis by delaying their death, thus suggesting a prosurvival function for eEF1A-2/S1 in skeletal muscle. In contrast, myotube death is accelerated by the introduction of the homologous gene, eEF1A-1/EF-1alpha, whereas cells transfected with antisense eEF1A-1/EF-1alpha are protected from apoptosis. These results demonstrate that the two sister genes, eEF1A-1/EF-1alpha and eEF1A-2/S1, regulate myotube survival with the former exerting prodeath activity and the latter a prosurvival effect.
Ruest
Louis-Bruno
LB
Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital, the Department of Medicine, McGill University, Montreal, Quebec H3T 1E2, Canada.
Marcotte
Richard
R
Wang
Eugenia
E
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism*; D002454:Cell Differentiation; D002470:Cell Survival; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D053938:DNA Fragmentation; D020287:In Situ Nick-End Labeling; D051379:Mice; D018482:Muscle, Skeletal / Q000166:cytology* / Q000378:metabolism; D018995:Myosin Heavy Chains / Q000378:metabolism; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D020648:Peptide Elongation Factor 1 / Q000096:biosynthesis* / Q000737:chemistry*; D010445:Peptide Elongation Factors / Q000096:biosynthesis*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D013997:Time Factors; D014018:Tissue Distribution; D014162:Transfection; D001616:beta-Galactosidase / Q000378:metabolism
C503235:Eef1a2 protein, mouse; D016376:Oligonucleotides, Antisense; D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors; D004247:DNA; D011065:Poly(ADP-ribose) Polymerases; D001616:beta-Galactosidase; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; D018995:Myosin Heavy Chains