Cutting axons with a laser allows the regeneration process to be studied. Chen et al. report that an RNA binding protein (called UNC-75 in worms and CELF2 in mice) promotes axon regeneration by controlling the alternative splicing of an mRNA that encodes a protein called Syntaxin. This process takes place in the nucleus of the nerve cell and essentially ‘tips the balance’ of alternative splicing towards an isoform of Syntaxin that is found predominantly in neurons (shown in dark blue and labeled “A”), and away from an isoform that is usually found in non-neuronal tissues (light blue; “B”). In fact, UNC-75 tips the balance so strongly that the Syntaxin isoform B was not found in neuronal tissues unless the gene for UNC-75 was mutated. It is not clear how the Syntaxin isoforms contribute to regeneration. It has been proposed that the Syntaxin proteins promote extra membrane to be added to the axon, possibly aiding in extending the axon after an injury (indicated by a “?”). It is also possible that different Syntaxin isoforms segregate into distinct regions of the axon membrane leading to the different functions of these isoforms.