2022.08.10 Turning the spotlight on cells in tissues

Light-Seq: Light-directed in situ barcoding of biomolecules in fixed cells and tissues for spatially indexed sequencing Journal: Nature Methods Application of Light-Seq to the mouse retina: To be able to specifically sequence the RNA molecules of neuronal cells in the functionally distinct layers of the mouse retina (graphic on the left), the team applied a new approach for “photocrosslinking” DNA barcodes to copies of RNA molecules in the retina’s individual light-selected layers (shown here in magenta, light blue and green). They then used a DNA nanotechnology-powered stitching technique to generate continuous sequences that could be mildly extracted from the tissue and eventually read via NGS. The cross-sections remained fully intact and were used for follow-up localizations of proteins encoded by RNA molecules that were enriched in the individual layers. Credit: Wyss Institute at Harvard University Barcoded dopaminergic amacrine cells (DAC) in the mouse retina: Light-Seq enabled the isolation of the full transcriptome of a very rare type of cell, known as “dopaminergic amacrine cell” (DAC, magenta), by retrieving merely four to eight individually barcoded cells per cross-section. DACs are extremely hard-to-isolate, also because of their intricate connections to other cells in the retina that were differently barcoded using Light-Seq. Credit: Wyss Institute at Harvard University