Evolutionary importance of translation elongation factor eEF1A variant switching: eEF1A1 down-regulation in muscle is conserved in Xenopus but is controlled at a post-transcriptional level

► Mammals have two eEF1A isoforms, eEF1A1 and eEF1A2 which switch expression in muscle. ► Xenopus species also have muscle-specific eEF1A2 and downregulate eEF1A1 in muscle. ► This switch is transcriptional in mammals but post-transcriptional in frogs. ► eEF1A switching in muscle is mechanistically different in different species.