NOP16 Nucleolar Protein Homolog (NOP16)

NOP16 was upregulated by estrogen treatment and c-Myc induction compared to untreated breast cancer cells. Electrophoretic mobility shift assay and chromatin immunoprecipitation showed that the NOP16 gene is a direct transcriptional target of c-Myc, which binds to the E-box consensus sequence in the NOP16 promoter. The deduced protein contains 178 amino acids. NOP16 was expressed in all 5 human hematopoietic cell lines examined. Immunofluorescence studies localized NOP16 to the nucleolus. Staining with fibrillarin (FBL) showed localization to distinct nucleolar compartments. NOP16 is not localized to the dense fibrillar compartment. Sucrose density gradient centrifugation of nuclear extracts localized NOP16 to a large ribonucleoprotein complex.