Deciphering tRNA repertoires and translation coordination during mouse early embryogenesis by ORACLE-tRNAseq

Translational control is vital during the maternal-to-zygotic transition (MZT), yet the landscape of embryonic transfer RNA (tRNA) pools has been difficult to explore. Here, we develop Optimized Reaction for Accurate Capture of Low-input Entities tRNA Sequencing (ORACLE-tRNAseq), enabling robust tRNA profiling from as few as five mouse oocytes. We map tRNA landscapes from oocyte to blastocyst, identifying a distinct transition to embryonic tRNA repertoires and upregulation of tRNA pseudogenes at the 4-cell stage. Integrated multi-omics analyses reveal that zygotic tRNA gene activation coincides with zygotic genome activation (ZGA) and correlates with H3K4me3 establishment and chromatin remodeling. By coupling ORACLE-tRNAseq with Ribo-seq, we demonstrate that embryonic tRNA anticodon pools coordinate with high translation-efficiency gene pools to preferentially establish the zygotic translation machinery, particularly from major ZGA onwards. Collectively, these findings provide a resource for understanding translational regulatory networks during early embryogenesis.