Figure 8From: The Met receptor tyrosine kinase prevents zebrafish primary motoneurons from expressing an incorrect neurotransmitterMet is required to prevent CaPs from expressing an inappropriate neurotransmitter. For each condition we examined eight spinal hemisegments per embryo. (a-c") Embryos at 26 hpf labeled with antibodies to GABA (red) and zn1 plus znp1 (green); (a',b',c') only the green channel is shown; (a",b",c") only the red channel of the micrographs shown in (a,b,c) is shown. CaPs expressed GABA in embryos injected with translation blocking (b-b") or splice blocking (c-c") met MOs, but not in controls (a-a"). Note that some CaPs in met MO-injected embryos also have ectopic axons within the spinal cord (arrows). (d-e") Embryos at 26 hpf labeled with riboprobes to gad1 (green) and islet2 (red). (d',e') Only the green channel is shown; (d",e") only the red channel of the micrographs shown in (d,e) is shown. In met MO-injected embryos, islet2-positive CaPs also express gad1 (e-e"), whereas these two genes are not co-expressed in CaPs of control embryos (d-d"). (f-g") Embryos at 26 hpf labeled with antibodies to GABA (red) and zn1 plus znp1 (green). (f',g') Only the green channel is shown; (f",g") only the red channel of the micrographs shown in (f,g) is shown. CaPs do not express GABA in embryos co-injected with met MO and mMet mRNA (f-f"), but do express GABA in embryos co-injected with met MO and lacZ mRNA (g-g"). (h,i) Embryos at 26 hpf labeled with antibodies to GABA (red) and Islet (green). CaPs co-express Islet and GABA in met MO-injected embryos (i) but not in controls (h). n = 80 embryos in (a); n = 128 embryos in (b); n = 24–32 embryos each for (c,e,f,g); n = 20 embryos for (h); n = 35 embryos for (i). The phenotype was seen in 70% of embryos injected with the splice-inhibitor MO and 80% of embryos injected with translation-blockers; in affected embryos all segments showed the phenotype. Rescue was seen in 90% of embryos injected with mMet mRNA and 0% of embryos injected with lacZ mRNA. Scale bars, 10 μm.Back to article page