Hanson, W.M. et al. J. Am. Chem. Soc. 138, 11073–11076 (2016).

The antigen receptor on a T lymphocyte consists of an α- and a β-chain, which together dictate the specificity of the cell's adaptive immune response. Single-cell RNA sequencing can be used to explore the diversity of T cell receptor sequences in an individual, but many high-throughput methods, including those that prime reverse transcription off of beads in microdroplets, sequence only transcript 3′ ends. Hanson et al. have now developed a way to synthesize two different barcoded primers on a single bead, using a mixture of 5′ phosphoramidite monomers with two different protecting groups at the 3′ position. Deprotection and chain extension of one barcoded primer can be followed by a second deprotection and primer synthesis step, thus enabling the capture and sequencing of full-length α- and β-chain RNA sequences from the same receptor at high throughput.