Fig. 5

Stable and bicistronic expression of Tomato and GFP fluorescent proteins in chick forelimbs following limb lateral plate electroporation. a Limb lateral plate of E2/HH13 chick embryos was electroporated with the pT2AL-CMV/βactin-Tomato-T2A-GFP stable vector containing the Tomato-T2A-GFP cassette under the control of a general promoter. Forelimbs were collected for wholemount visualisation of Tomato or GFP, 3 (b, c), 5 (d–g) and 6 (l) days after electroporation. h, i Transverse sections of forelimbs 5 days after electroporation to visualise Tomato expression in limbs. j, k Tomato fluorescence was observed in limb connective tissues and never observed in muscle differentiated (j) or progenitor (k) cells. l Forelimbs were collected for wholemount visualisation of Tomato 6 days after electroporation. m–r In situ hybridisation experiments to transverse limb sections of the electroporated forelimb shown in L, with GFP (m, o, q) and Scx (n, p, r) probes at the level of the proximal (m, n) and distal (o–r) forearm. m, n and o, p are adjacent sections. m, n shows strong GFP expression in regions surrounding cartilage elements (arrow). o–r GFP expression in tendons. q, r is a high magnification of a tendon shown in (o, p arrowed). ca, cartilage, u, ulna, r, radius