Human ribosomal RNA (rRNA) (rRNA)

Human ribosomal RNA (rRNA) is the central component of the ribosome, serving as both a structural scaffold and the catalytic engine (ribozyme) for protein synthesis in all human cells (Montanaro et al., 2008). It is synthesized in the nucleolus, where RNA Polymerase I transcribes a 45S precursor that is processed into 18S, 5.8S, and 28S rRNAs, while RNA Polymerase III produces the 5S rRNA (Grummt, 2003). The 28S rRNA is particularly critical as it contains the peptidyl transferase center responsible for forming peptide bonds during translation (Endo & Tsurugi, 1987). In many cancers, rRNA synthesis is significantly upregulated to meet the high protein demand of rapidly dividing cells, making it a strategic target for anti-tumor therapies (Pelletier et al., 2018). Therapeutic agents like CX-5461 (Pidnarulex) act by inhibiting the transcription of rRNA, thereby inducing nucleolar stress and activating p53-mediated cell cycle arrest (Drygin et al., 2011). Additionally, human rRNA is the direct target of ribosome-inactivating proteins like ricin, which halts translation by depurinating a specific adenine residue in the 28S rRNA (Endo & Tsurugi, 1987).

Other names

Ribosomal ribonucleic acid18S ribosomal RNA28S ribosomal RNA5.8S ribosomal RNA5S ribosomal RNACytoplasmic rRNA

Inhibition of RNA Polymerase I-mediated transcription of ribosomal DNA into pre-rRNA; site-specific enzymatic depurination of the sarcin-ricin loop in the 28S rRNA subunit which prevents elongation factor binding.