Solid-phase synthesis of highly repetitive chromatin assembly templates

•Solid-phase DNA ligation method to generate unique chromatin model system templates.•Optimized to produce either desired template length or diversity of template sizes.•DNA ligation monomers include both single and multi-nucleosome binding sites.•Synthesized templates assemble into chromatin model systems.

DNA templates for assembling chromatin model systems typically consist of numerous repeats of nucleosome positioning sequences, making their synthesis challenging. Here we describe a solid-phase strategy for generating such templates using sequential enzymatic ligation of DNA monomers. Using single nucleosome site monomers, we can either generate a twelve-nucleosome site target, or systematically access intermediate-sized templates. Using twelve nucleosome positioning site monomers, longer templates can be generated. Our synthesized templates assemble into well-defined chromatin model systems, demonstrating the utility of our solid-phase approach. Moreover, our strategy should be more widely applicable to generating other DNAs containing highly repetitive DNA sequences.