Figure 6

Azide effectively quenches residual peroxidase activity in multicolor FISH. (A-D) The efficacy of several peroxidase quenching compounds was compared by performing multicolor FISH for Smed-CAVII-1 (expressed at high levels in protonephridia) and Smed-PKD1 (expressed at moderate levels in a subset of neurons). CAVII-1 expression was detected, then residual peroxidase activity was quenched by incubating samples for 45 min with either 2% hydrogen peroxide (A), 4% formaldehyde (B), glycine buffer pH 2.0 (C), or 100 mM azide (D). Finally, a second TSA reaction to detect expression of PKD1 was performed. Arrows indicate signal from residual peroxidase activity of CAVII-1 in the green channel. Scale bar: 100 μm.