However, this method of injection was easily adapted to adult mice (2–3 months old FVB mice) as it had the added bonus of opening up the possibility to extend our findings on the role played by GAP-43 in maintaining CF structure to other in vivo studies (such as in combination with genetically modified mouse models or with time-lapse imaging by multi-photon microscopy). Here, GAP43 is linked to cystic fibrosis.