Component of ribonuclease P, a ribonucleoprotein complex that generates mature tRNA molecules by cleaving their 5'-ends (PubMed:22641852). Also a component of the MRP ribonuclease complex, which cleaves pre-rRNA sequences (PubMed:22549728). Required for rRNA maturation, including 5.8S rRNA processing (PubMed:22549728). Component of nuclear RNase P and RNase MRP ribonucleoproteins (PubMed:22641852). RNase P consists of a catalytic RNA moiety and different protein chains (By similarity). Several subunits of RNase P are also part of the RNase MRP complex (By similarity). RNase MRP consists of a catalytic RNA moiety and several protein subunits (By similarity). Accumulation of unprocessed cytosolic rRNA precursors, especially the large 35S rRNA precursor, as well as of the internal transcribed spacer 1 (ITS1) fragment corresponding to the region between the 18S and 5.8S rRNAs that contains the A3 cleavage sites.