Fig. 5

Activated PKA expression in Schwann cells rescues mbp expression in gpr126 mutants. (A,B,D,F) Lateral views of 3 dpf zebrafish embryos showing expression of mbp mRNA. (C,E) Confocal microscope images showing expression of the indicated EGFP reporter constructs. Anterior is to the left and dorsal to the top in all images. (A) mbp is expressed in the PNS of a control gpr126^st49/+ embryo, including the PLLn (white arrow), the anterior lateral line (black arrowheads) and cranial ganglia (black arrow) (n=20). Expression is also observed in the CNS (white asterisk). (B) mbp is expressed in the CNS (white asterisk) but not the PNS in a control gpr126^st49/st49 mutant embryo (compare expression in A with that in B) (n=10). (C) Zebrafish embryo (3 dpf) injected with the huC:EGFP reporter construct, which drives expression in the nervous system. The white arrow points to axons of the PLLn. Expression was observed in the PLLn of all embryos analyzed (n=8). (D) mbp expression in a gpr126^st49/st49 mutant embryo injected with the huC:PKA^act transgene. Expression is identical to that seen in control mutant embryos (compare D with B). No mbp expression was observed in the PNS (n=70). (E) 2 dpf zebrafish embryo injected with the sox10:EGFP reporter construct. White arrow points to Schwann cells along the PLLn. Expression in Schwann cells was observed in 13% (n=3/24) of injected embryos. (F) mbp expression in a gpr126^st49/st49 embryo injected with the sox10:PKA^act transgene. Rescued mbp expression is observed in clones of Schwann cells along the PLLn (white arrows), the anterior lateral line (black arrowheads) and cranial ganglia (black arrow). mbp expression was observed in the PNS in 15% (n=8/52) of injected embryos. Scale bars: 100 μm.