Pseudouridine-modified tRNA fragments repress malignant protein synthesis and predict leukemic progression in myelodysplastic syndrome

ABSTRACT: Transfer RNA (tRNA)-derived fragments (tRF) are emerging small noncoding (nc) RNAs that, while commonly altered in cancer, have poorly defined roles in tumorigenesis. Here we show that pseudouridylation (Ψ) of a stem-cell-enriched tRF subtype, mTOG, selectively inhibits malignant protein synthesis programs, thereby promoting engraftment and differentiation of myelodysplastic syndrome (MDS) hematopoietic stem and progenitor cells (HSPC). Building on evidence that mTOG-Ψ target the polyadenylate-binding protein cytoplasmic 1 (PABPC1), we employed HDX-MS to reveal critical interactions between mTOG and functional RNA-recognition motif (RRM) domains in PABPC1. Mechanistically, this hinders the recruitment of the translational co-activator PABPC1-interacting protein 1 (PAIP1) and strongly represses translation of transcripts sharing 5’UTR pyrimidine-enriched sequences (PES), including 5’ terminal oligopyrimidine tracts (TOP) that encode protein machinery components, and are frequently altered in cancer. Significantly, mTOG dysregulation leads to aberrantly increased 5’PES mRNA translation in malignant MDS-HSPC and is clinically associated with leukemic transformation and reduced patient survival. Taken together, these results define a critical role for tRF and Ψ in difficult-to-treat subsets of MDS characterized by high risk of progression to acute myeloid leukemia.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

DISEASE(S): Myelodysplastic Syndrome,Myeloid Leukemia

SUBMITTER: Simon Ekström  

LAB HEAD: Cristian Bellodi

PROVIDER: PXD023122 | Pride | 2021-12-20

REPOSITORIES: Pride