Nanobody-tethered transposition enables multifactorial chromatin profiling at single-cell resolution

Chromatin states are functionally defined by a complex combination of histone modifications, transcription factor binding, DNA accessibility and other factors. Current methods for defining chromatin states cannot measure more than one aspect in a single experiment at single-cell resolution. Here we introduce nanobody-tethered transposition followed by sequencing (NTT-seq), an assay capable of measuring the genome-wide presence of up to three histone modifications and protein-DNA binding sites at single-cell resolution. NTT-seq uses recombinant Tn5 transposase fused to a set of secondary nanobodies (nb). Each nb-Tn5 fusion protein specifically binds to different immunoglobulin-G antibodies, enabling a mixture of primary antibodies binding different epitopes to be used in a single experiment. We apply bulk-cell and single-cell NTT-seq to generate high-resolution multimodal maps of chromatin states in cell culture and in human immune cells. We also extend NTT-seq to enable simultaneous profiling of cell surface protein expression and multimodal chromatin states to study cells of the immune system. Cell surface protein expression and multiple epigenetic features are mapped simultaneously in single cells.

Automated summary

NTT-seq is a novel experimental method capable of measuring the presence of multiple histone modifications and protein-DNA binding sites at single-cell resolution. It utilizes recombinant Tn5 transposase fused to secondary nanobodies that specifically bind different immunoglobulin-G antibodies. By applying NTT-seq, high-resolution multimodal maps of chromatin states can be generated and it can be extended to study cell surface protein expression and multimodal chromatin states simultaneously.