Elucidating gene expression programs within a cell-specific manner is a grand challenge for biologists. Harder still is the ability to have kinetic control over such experiments. Metabolic labeling with bioorthogonally-functionalized metabolic intermediates provides a means to profile RNA expression in a cell-specific manner, but there is still a lack of kinetic resolution. Herein we present the synthesis and evaluation of photocaged metabolic uracil intermediates. We compare the photo-decaging properties and demonstrate their utility in metabolic labeling experiments in a cell-specific manner. We anticipate that our approach will have far-reaching impact as it provides control over tagging of nascent RNA
