text: Malignant tumors often express higher levels of the AgNOR proteins found in this structure.
full_question: Malignant tumors often express higher levels of the AgNOR proteins found in this structure. Barbara McClintock was the first to describe this structure's formation around a namesake organizer region. A hairpin-hinge-hairpin-tail motif containing ANANNA and ACA consensus sequences is found in a molecule specific to this structure called box H-slash-ACA, which guides pseudouridylation. The granular region encapsulates its fibrillar and dense fibrillar centers. This structure's snoRNAs process the rRNA transcribed within it. It is typically spherical and stains darker than the surrounding nucleoplasm. For 10 points, name this structure that synthesizes ribosomes and is found in the nucleus.
first_sentence: Malignant tumors often express higher levels of the AgNOR proteins found in this structure.
raw_answer: nucleolus [prompt on nucleus before "organizer" is read]