Fig. 4.

ncRNA and ribosome biogenesis. a There is a strong link between miRNA and ribosome biogenesis. miR-424-5p is elevated and targets the RNA Pol I pre-priming complex factors POLR1A and UBTF, which in turn downregulate mature rRNA levels. miR-20a, miR-194, and miR-206 inhibit Ncl expression by binding to the 3’UTR of Ncl, thereby affecting the subsequent splicing and processing of 47S pre-RNA. miR-595 inhibits ribosome biogenesis by reducing the expression of RPL27A and the synthesis of the mature 60S subunit. b Increased expression of lncRNA inhibits rDNA transcription through modification of rDNA chromatin, resulting in reduced pre-rRNA levels, mature rRNA levels, and overall translation. c circRNA recruits the 40S ribosomal subunit and initiates mRNA translation and protein synthesis. lncRNA long noncoding RNA, Ncl nucleolin, rDNA ribosomal RNA, pol Ι RNA polymerase Ι