Large-scale analysis of loss of chromosome Y in human pluripotent stem cells: Implications for Turner syndrome and ribosomopathies.

Loss of chromosome Y (LOY) occurs in aging and cancers, but its extent and implications in human embryonic stem cells (hESCs) have not been studied. Here, we analyzed over 2,650 RNA sequencing (RNA-seq) samples from hESCs and their differentiated derivatives to detect LOY. We found that 12% of hESC samples have lost their chromosome Y and identified LOY in all three germ layers. Differential expression analysis revealed that LOY samples showed a decrease in expression of pluripotency markers and in ribosomal protein (RP) genes. Strikingly, significant RP transcription downregulation was observed in most RP genes, although there is only one expressed Y-linked RP gene. We further analyzed RP expression in Turner syndrome and Diamond-Blackfan anemia samples and observed overall downregulation of RP transcription. This broad analysis sheds light on the scope and effects of LOY in hESCs, suggesting a novel dosage-sensitive mechanism regulating RP gene transcription in LOY and autosomal ribosomopathies.