RNAs18S

18S ribosomal RNA, often abbreviated as 18S rRNA, is a major component of the small ribosomal subunit in eukaryotes. It is a non-coding RNA molecule, meaning it does not translate into a protein, but rather plays a crucial structural and catalytic role in protein synthesis. The "18S" designation refers to its sedimentation coefficient, a measure of how quickly it moves in a centrifuge, which is approximately 18S. This RNA molecule is encoded by genes that are typically present in multiple copies within the genome. The 18S rRNA, along with ribosomal proteins, assembles to form the 40S ribosomal subunit. This subunit then interacts with the 60S ribosomal subunit to form the complete 80S ribosome, the cellular machinery responsible for translating messenger RNA (mRNA) into proteins. The 18S rRNA is highly conserved across eukaryotic species, reflecting its fundamental importance in the translation process. Its sequence and structure are critical for binding mRNA, recruiting transfer RNAs (tRNAs), and catalyzing the formation of peptide bonds. Due to its conserved nature and abundance, 18S rRNA is frequently used as a target for molecular identification, phylogenetic studies, and as a reference gene in gene expression analyses.