scRNA-seq for Microcephaly Research [I]: Single-Cell Droplet Encapsulation, mRNA Capture, and cDNA Synthesis.

Single-cell RNA sequencing (scRNA-seq) allows for the transcriptomic profiling of a sample tissue with single-cell resolution. The concept of scRNA-seq builds on traditional, "bulk" RNA-seq by recording and preserving the cellular origin of each transcript throughout library preparation. Here we describe an adaptation of the Drop-Seq method (Macosko et al. Cell 161, 1202-1214, 2015), in which nanoliter-scale droplets are used to physically separate dissociated cells, while a cell-specific DNA barcode is simultaneously introduced. Following barcoding, cDNAs can be mixed and pooled while retaining the identity of the cell of origin. The benefit of the Drop-Seq approach is high throughput from relatively small samples of tissue. The method described here is appropriate for processing an input of as few as 150,000 cells, with a final yield of as many as 5000 single-cell transcripts captured.