library_construction_protocol: RNA was harvested using Trizol reagent. 120 ug of total RNA for the construction of sequencing libraries. After quantifying the total RNA using NanoDrop ND-1000, intact mRNA was purified and fragmented into approximately 300nt segments. RNA fragments containing m1A modification sites were enriched via immunoprecipitation using an anti-N1-methyladenosine (m1A) antibody. Sequencing libraries for both m1A-enriched mRNA and input mRNA were constructed using the KAPA Stranded mRNA-seq Kit. The library mRNA was pooled and denatured into single-stranded DNA. After adapter ligation, it was bound to Illumina flow cells for in situ amplification, followed by 150bp sequencing on the Illumina NovaSeq 6000.