Protocol for the use of signal amplification by exchange reaction-fluorescence in situ hybridization on adult formalin-fixed paraffin-embedded mouse lung tissue

Fluorescence in situ hybridization (FISH) is a useful tool for analyzing RNA expression, but difficulties arise with low-abundance RNA and in tissues that are formalin-fixed paraffin-embedded (FFPE) because reagents can be expensive. In this protocol, we adapt a previously designed FISH amplification protocol (SABER [signal amplification by exchange reaction]) for adult mouse FFPE lung sections by using probes that are extended and branched to amplify the signal. We combine FISH and immunostaining to identify cell-specific RNA. For complete details on the use and execution of this protocol, please refer to Kishi et al.¹ and Lyu et al.²