In molecular biology, the 5.8S ribosomal RNA (5.8S rRNA) is a non-coding RNA component of the large subunit of the eukaryotic ribosome and so plays an important role in protein translation.

It is transcribed by RNA polymerase I as part of the 45S precursor that also contains 18S and 28S rRNA.

[3] The 5.8S ribosomal RNA is used to better understand other rRNA processes and pathways in the cell.

In eukaryotes, the insertion of ITS2 breaks LSU rRNA into 5.8S and 28S rRNAs.

This is accomplished through a continuous cleavage pathway performed by both endonuclease and exonuclease enzymes, cutting the spacers at specific locations.