Ribosomal RNA 2'-O-methylation dynamics impact cell fate decisions

Translational regulation impacts both pluripotency maintenance and cell differentiation. To what degree the ribosome itself exerts control over this process remains unanswered. Accumulating evidence has demonstrated heterogeneity in ribosome composition in various organisms. 2'-O-methylation of rRNA represents an important source of heterogeneity, where site-specific alteration of methylation levels can modulate translation. Here we explore changes in rRNA 2'-O-methylation during mouse brain development and during tri-lineage differentiation of human embryonic stem cells. We find distinct alterations between brain regions, as well as clear dynamics during cortex development and germ layer differentiation. We identify a methylation site which impacts neuronal differentiation. Modulation of its methylation levels affects ribosome association of the Fragile X Mental Retardation Protein and translation of WNT pathway-related mRNAs. Together, the data reveals ribosome heterogeneity through rRNA 2'-O-methylation during early development and differentiation and suggests a direct role for ribosomes in regulating translation during cell fate acquisition. ### Competing Interest Statement The authors have declared no competing interest.