Figure 3. Further evidence of cytoplasmic transfer between donor and host.

(a–d) Donor cells collected from P1–3 DsRed mice, which were also homozygous for the rd1 mutation were transplanted into adult Nrl-GFP mice in which rods are labelled with GFP. Three weeks after transplantation, a DsRed and GFP-positive photoreceptor cell bodies were seen. (e–h) To confirm cytoplasmic transfer of proteins using a Cre-lox recombination, donor cells (CAG-LSL-tdTomato, Nrl-GFP) at P7 were transplanted into adult Crx-Cre host mice. Three days post transplantation, donor cells in the subretinal space are GFP positive as expected, whereas in the host ONL (white box) a double-labelled (GFP and tdTomato) cell body is visible, confirming that Cre had passed from host photoreceptor to donor cell to activate tdTomato, which then retrogradely labelled the host photoreceptor together with GFP.