Droplet digital PCR for measuring absolute copies of gene transcripts in human islet-derived progenitor cells

Transcript analysis is a routinely used method to assess the expression profile of progenitor cells at different stages starting from their isolation to differentiation into specific lineages. It is a powerful way to understand similarities and differences between different cell types as well to estimate successful differentiation process. Transcript measurement is most commonly done using polymerase chain reaction (PCR) but other methods such as in situ hybridization, RNA sequencing are available. The quantitative PCR using TaqMan chemistry is a highly sensitive and reproducible method that measures gene transcripts as a relative abundance. With recent advances in technology, absolute quantitation of genes to single copy level is possible using digital PCR platforms. Digital PCR is an improved method of PCR in which a single reaction is partitioned into multiple mini reactions. Gene transcripts are measured in each of these mini reactions thereby improving assay sensitivity and making absolute quantitation possible. Here we describe the generation of human islet-derived progenitor cells and measuring gene transcripts in these cells at different passages using digital droplet PCR.