Component of the ribosome, a large ribonucleoprotein complex responsible for the synthesis of proteins in the cell. The small ribosomal subunit (SSU) binds messenger RNAs (mRNAs) and translates the encoded message by selecting cognate aminoacyl-transfer RNA (tRNA) molecules. The large subunit (LSU) contains the ribosomal catalytic site termed the peptidyl transferase center (PTC), which catalyzes the formation of peptide bonds, thereby polymerizing the amino acids delivered by tRNAs into a polypeptide chain. The nascent polypeptides leave the ribosome through a tunnel in the LSU and interact with protein factors that function in enzymatic processing, targeting, and the membrane insertion of nascent chains at the exit of the ribosomal tunnel. Seems involved in the regulation of cell proliferation (PubMed:19392710). Essential in leaf polarity establishment, probably having a role for translation in leaf dorsoventral patterning to specify leaf adaxial identity (PubMed:18305007). Component of the large ribosomal subunit (LSU). Moderate reduction in cell number (PubMed:19392710). Abnormal leaf patterning, with the abaxial mesophyll features appearing in the adaxial mesophyll domain (PubMed:18305007). Double mutants oli2 oli7 have further reduced cell number but exhibit also excessive postmitotic cell enlargement in leaves (compensation phenotype) (PubMed:19392710). Plant missing both OLI7 and GIF1/AN3 have a strong compensation phenotype (PubMed:19392710). Belongs to the universal ribosomal protein uL18 family.