library_construction_protocol: Total RNA was isolated as published (Grützner et al., 2021, Nucelic Acids Res. 49(6), doi: 10.1093/nar/gkab146) RNA was processed as published (Grützner et al., 2021, Nucleic Acids Res. 49(6), doi: 10.1093/nar/gkab146); NEBnext Multiplex Small RNA Library Prep Set