Describing an assay used to identify the genes being transcribed at a particular instant. Rapidly isolated nuclei are incubated with labelled nucleotides which generates labelled RNAs from those that were stalled because of lack of nucleotides. The labelled RNA can then be used as a probe to identify corresponding cDNAs. Probably more accurately described as a run-off assay, but the terms are used interchangeably.
Subjects: Medicine and Health — Chemistry.