SHPRH as a new player in ribosomal RNA transcription and its potential role in homeostasis of ribosomal DNA repeats

There are hundreds of copies of rDNA repeats in mammalian chromosomes and the ratio of active, poised, or inactive rDNA is regulated in epigenetic manners. Recent studies demonstrated that a post-DNA replication repair enzyme, SHPRH affects rRNA transcription by recognizing epigenetic markers on rDNA promoters and unveiled potential links between DNA repair and ribosome biogenesis. This study suggests that SHPRH could be a link between mTOR-mediated epigenetic regulations and rRNA transcription, while concomitantly affecting genomic integrity.