《英文msh词典》Nucleolus,Cell
[入口词] Nucleolus,Cell
[主题词] Cell Nucleolus
[英文释义] Within most types of eukaryotic CELL NUCLEUS,a distinct region,not delimited by a membrane,in which some species of rRNA (RNA,RIBOSOMAL) are synthesized and assembled into ribonucleoprotein subunits of ribosomes. In the nucleolus rRNA is transcribed from a nucleolar organizer,i.e.,a group of tandemly repeated chromosomal genes which encode rRNA and which are transcribed by RNA polymerase I. (Singleton & Sainsbury,Dictionary of Microbiology & Molecular Biology,2d ed)