Detection of single influenza viral RNA in cells using a polymeric sequence probe.

A polynucleotide probe, call a polymeric sequence probe (PSP), was used to detect influenza A (Influenza A/WSN/33) NA (Neuraminidase) viral RNA in Madin-Darby canine kidney (MDCK) cells. The PSP is a single-stranded DNA molecule with ~2,000 tandem repeat fluorescence binding sites and target binding sites that can bind with multiple fluorescence complementary oligos and target viral RNA using a fluorescence in situ hybridization (FISH) process. A single viral RNA labeled by PSP can be directly observed in MDCK cells. The simple FISH protocol enables the observation and quantitative analysis of the infectious process and drug effects with ultrahigh sensitivity and spatial resolution.