NPOM-Caged-dT substitutions allow for the function of an oligonucleotide to be controlled by light. The nucleotide cannot participate in Watson-Crick base pairing when the bulky NPOM group is attached to the N3 of thymidine. However, on exposure to low energy UV light, the NPOM group is removed, releasing the native thymidine. This simple and effective mechanism known as ‘photocaging’ has proven to be relatively popular in biological settings. In addition to vfCRISPR,1 this nucleotide has recently played key roles in facilitating the mapping of single cell transcriptomes2 and the deep sequencing of non-enzymatic RNA primer extension.3
Oligonucleotides with caged thymidines are relatively easy to prepare. NPOM Caged-dT-CE Phosphoramidite will be used in place of dT-CE Phosphoramidite in select locations, and no changes to coupling times or deprotection procedures are necessary. As with any light-sensitive modification, exposure to light should be minimized.