Fig. 6. Newly differentiating white matter astrocytes express Fgfr3. We simultaneously hybridised sections of E18 mouse cervical spinal cord with an FITC-labelled Gfap mRNA probe (A) and a DIG-labelled Fgfr3 probe (B). The Gfap and Fgfr3 hybridisation signals were visualised and photographed sequentially (see Materials and Methods). All the Gfap-expressing astrocytes also expressed Fgfr3 (e.g. arrows). In general, Fgfr3⁺ cells in the grey matter (arrowheads) did not co-express Gfap.