Figure 1
From: RNase MRP and the RNA processing cascade in the eukaryotic ancestor
The eukaryotic RNA-processing cascade. mRNA is cleaved by the spliceosome (comprised of snRNAs and proteins) to release the processed mRNA and introns. Some introns contain snoRNAs which in turn modify snRNAs, tRNAs and rRNAs. RNase P (P) cleaves pre-tRNA while RNase MRP (MRP) cleaves rRNA. The ribosomal complex (comprised of rRNAs) brings the tRNAs and mature mRNAs together for translation. The involvement of RNase P in pre-rRNA processing has been questioned recently in [59].