Live Imaging of Nuclear RNPs in Mammalian Complex Tissue with ECHO-liveFISH

Multiplex RNA detection with fluorescence microscopy offers high spatial and temporal resolution required for addressing complex behaviors of RNA in living cells. Using chemically engineered linear oligonucleotide probes that emit fluorescence upon hybridization to target RNA, we have devised an imaging method suitable for studies of the dynamic regulation of nuclear RNPs, an important and yet poorly understood cellular pathway of gene expression. This new method labels specific sequences of RNA components in RNPs and thus avoids overexpression of fluorescent marker proteins that may result in entangled experimental results. Using this method, we observe in living brain tissue spatially constrained nuclear RNA foci under dynamic regulation in response to cellular transcriptional activity with individual cell heterogeneity.