UNR is a 798 amino acid protein that localizes to the cytoplasm and contains nine CDS (cold shock) domains. Existing as a component of the multi-protein autoregulatory ribonucleoprotein complex (ARC), UNR functions as an RNA-binding protein that is required for the initiation of rhinovirus RNA translation and is thought to be involved in translationally coupled mRNA turnover. UNR is expressed as two isoforms, designated long and short, and shares over 98% amino acid identity with its rat counterpart, suggesting a conserved role between species. The gene encoding UNR maps to human chromosome 1, which spans 260 million base pairs, contains over 3,000 genes and comprises nearly 8% of the human genome.