Uncovering cell type‐specific complexities of gene expression and RNA metabolism by TU‐tagging and EC‐tagging

Cell type‐specific transcription is a key determinant of cell fate and function. An ongoing challenge in biology is to develop robust and stringent biochemical methods to explore gene expression with cell type specificity. This challenge has become even greater as researchers attempt to apply high‐throughput RNA analysis methods under in vivo conditions. TU‐tagging and EC‐tagging are in vivo biosynthetic RNA tagging techniques that allow spatial and temporal specificity in RNA purification. Spatial specificity is achieved through targeted expression of pyrimidine salvage enzymes (uracil phosphoribosyltransferase and cytosine deaminase) and temporal specificity is achieved by controlling exposure to bioorthogonal substrates of these enzymes (4‐thiouracil and 5‐ethynylcytosine). Tagged RNAs can be purified from total RNA extracted from an animal or tissue and used in transcriptome profiling analyses. In addition to identifying cell type‐specific mRNA profiles, these techniques are applicable to noncoding RNAs and can be used to measure RNA transcription and decay. Potential applications of TU‐tagging and EC‐tagging also include fluorescent RNA imaging and selective definition of RNA–protein interactions. TU‐tagging and EC‐tagging hold great promise for supporting research at the intersection of RNA biology and developmental biology. This article is categorized under: Technologies > Analysis of the Transcriptome