The  transpeptidase sortase A, binds nucleic acids, which can be used and to mediates their cell labeling
We found the transpeptidase Sortase A also binds nucleic acids and mediates mammalian cell labeling. We confiremed the labeling reaction  using . Furthermore, a variety of additional classes of wild-type sortase and engineered mutants of sortase A exhibited the ability to label the surface of mammalian cells with nucleic acids. Heparin on the cell surface appears to be involved, and sortase might serve as an anchor for the nucleic acids. Interestingly, the bacterial sortases of Staphylococcus aureus spontaneously bind extracellular oligonucleotides, which seems to be related to the involvement of sortase and the participation of extracellular nucleic acids in the formation of bacterial biofilms. Finally, we utilized the cell-labeling capability of mgSrtA to enable highly efficient and ready-to-use multiplexed cell labeling for single-cell RNA-seq (scRNA-seq). Overall design: In SMART-seq experiment, cells were labeled with oligos at first and the oligo were captured by SMART-seq kit. In CRISPR screening experiment, cells were labeled with the oligo modified by fluorescents and sorted by flow cytometry before prepared library. In scRNA-seq experiment, cells from different samples were labeled separately and mixed before loaded to the 10× microfluidics lane.