The nucleolar RNA (nRNA) is part of the nucleolus. It originates from the region of DNA called the nucleolar organizing region (NOR). This 45 S single-stranded RNA associates with proteins from the cytoplasm to form ribosome subunits .
By BruceBlaus. When using this image in external sources it can be cited as:Blausen.com staff. "Blausen gallery 2014". Wikiversity Journal of Medicine. DOI:10.15347/wjm/2014.010. ISSN 20018762. (Own work) [CC BY 3.0], via Wikimedia Commons