ribosomemRNA

Ribosome mRNA, or ribosomal protein mRNA, refers to messenger RNA transcripts that encode the ribosomal proteins which are components of the ribosome. These proteins combine with ribosomal RNA to build the small and large subunits that carry out protein synthesis. Ribosome mRNAs are distinct from rRNA genes and from mRNAs that encode other cellular proteins.

In bacteria, ribosomal protein genes are typically organized into operons and transcribed into polycistronic mRNA, allowing coordinated production of multiple ribosomal proteins. Translation initiation is guided by bacterial ribosome binding sites, and expression levels often correlate with growth conditions and nutrient availability.

In eukaryotes, ribosomal protein genes are numerous and usually transcribed individually by RNA polymerase II. Their transcripts are processed as typical capped and polyadenylated mRNAs and possess regulatory untranslated regions. Some vertebrate ribosomal protein mRNAs contain a 5' terminal oligopyrimidine tract (5' TOP), which makes their translation particularly responsive to mTOR signaling and cellular nutrient status, linking ribosome production to growth conditions.

Function and significance: the ribosomal proteins encoded by ribosome mRNAs assemble with ribosomal RNA to form functional ribosomes, enabling global protein synthesis. The expression of RP mRNAs is tightly coordinated with rRNA transcription and ribosome biogenesis to maintain proper subunit stoichiometry. Disruptions in this coordination can affect cell growth and are associated with ribosomopathies and related disorders.