NUCLEOPHOSMIN AND NUCLEOLIN: ENCODING GENES AND EXPRESSION IN VARIOUS HUMAN AND ANIMAL TISSUES
Argirophilic proteins of nucleolar organizer regions (Ag-NOR) pose a wide group of nucleolar proteins specifically stained by AgNO3. Expression level of Ag-NOR proteins in proliferating cells, including tumor ones, is commonly high. Nucleophosmin/B23 and nucleolin/C23 account for 70% of Ag-NOR proteins; B23 and C23 are involved into regulation of RNA polymerase function, DNA transcription, replication and recombination, RNA processing, mRNA and chromatin stabilization, mitosis and apoptosis regulation. Overexpression of B23/C23 was revealed in various proliferative diseases including malignant neoplasmas and in human tumor xenographts implanted into animals with immunodeficiency. Cell proliferation rate and malignancy progression in vitro or in vivo mainly depends on B23/C23 expression. The values of Ag-NOR count and subjective Ag-NOR pattern assessment score as well as structure and expression of B23/C23 encoding genes in various tumors are important issues related to the field of experimental oncology. In the review the results of the most important studies analyzing the expression of nucleophosmin and nucleolin in human and animal tumors are considered.