RT Journal Article SR Electronic T1 N-6-methyladenosine (m6A) promotes the nuclear retention of mRNAs with intact 5′ splice site motifs JF Life Science Alliance JO Life Sci. Alliance FD Life Science Alliance LLC SP e202403142 DO 10.26508/lsa.202403142 VO 8 IS 2 A1 Lee, Eliza S A1 Smith, Harrison W A1 Wang, Yifan E A1 Ihn, Sean SJ A1 Scalize de Oliveira, Leticia A1 Kejiou, Nevraj S A1 Liang, Yijing L A1 Nabeel-Shah, Syed A1 Jomphe, Robert Y A1 Pu, Shuye A1 Greenblatt, Jack F A1 Palazzo, Alexander F YR 2025 UL https://www.life-science-alliance.org/content/8/2/e202403142.abstract AB In humans, misprocessed mRNAs containing intact 5′ Splice Site (5′SS) motifs are nuclear retained and targeted for decay by ZFC3H1, a component of the Poly(A) Exosome Targeting complex, and U1-70K, a component of the U1 snRNP. In S. pombe, the ZFC3H1 homolog, Red1, binds to the YTH domain–containing protein Mmi1 and targets certain RNA transcripts to nuclear foci for nuclear retention and decay. Here we show that YTHDC1 and YTHDC2, two YTH domain-containing proteins that bind to N-6-methyladenosine (m6A) modified RNAs, interact with ZFC3H1 and U1-70K, and are required for the nuclear retention of mRNAs with intact 5′SS motifs. Disruption of m6A deposition inhibits both the nuclear retention of these transcripts and their accumulation in YTHDC1-enriched foci that are adjacent to nuclear speckles. Endogenous RNAs with intact 5′SS motifs, such as intronic poly-adenylated transcripts, tend to be m6A-modified at low levels. Thus, the m6A modification acts on a conserved quality control mechanism that targets misprocessed mRNAs for nuclear retention and decay.miCLIP-seq data are available at Gene Expression Omnibus (GEO, https://www.ncbi.nlm.nih.gov/geo/) with the accession code GSE230846 for the series, which contains several other datasets that have been recently published (Nabeel-Shah et al, 2024).