Methods in Brief

Genetics: A human tRNA atlas

Gogakos, T. et al. Cell Rep. 20, 1463–1475 (2017).

tRNAs are one of the classic models for noncoding RNAs. Decades of research have explored their role in translation; more recently, however, this role has expanded to include other regulatory functions. To understand the scope of these functions, Gogakos et al. developed hydro-tRNAseq to annotate all tRNA genes. The authors subjected a 60–100-nt fraction of total RNA to limited alkaline hydrolysis to remove structure and modifications and thus created a cDNA library with substantially increased tRNA levels. Iterative mapping provided the researchers with a comprehensive map of tRNA genes. To refine the annotation, they combined the data with photo-activatable crosslinking and immunoprecipitation (PAR-CLIP) of a protein involved in pre-tRNA processing. The authors present a human tRNA atlas that includes tRNA expression levels.