Human 28s rRNA 5’ terminal derived small RNA inhibits ribosomal protein mRNA levels

Abstract

Recent small RNA (sRNA) high-throughput sequencing studies reveal ribosomal RNAs (rRNAs) as major resources of sRNA. By reanalyzing sRNA sequencing datasets from Gene Expression Omnibus (GEO), we identify 28s rRNA 5 terminal derived sRNA (named 28s5-rtsRNA) as the most abundant rRNA-derived sRNAs. These 28s5-rtsRNAs show a length dynamics with identical 5 end and different 3 end. Through exploring sRNA sequencing datasets of different human tissues, 28s5-rtsRNA is found to be highly expressed in bladder, macrophage and skin. We also show 28s5-rtsRNA is independent of microRNA biogenesis pathway and not associated with Argonaut proteins. Overexpression of 28s5-rtsRNA could alter the 28s/18s rRNA ratio and decrease multiple ribosomal protein mRNA levels. Our results reveal that 28s5-rtsRNA serves as a key regulator in ribosomal protein expression.