title: Activity of a 40 kDa RNA-binding protein correlates with MYCN and c-fos mRNA stability in human neuroblastoma.
abstract: Subclones of neuroblastic (N) and substrate adherent (S) cells have been established from neuroblastoma tumours cultured in vitro which differ in growth characteristics and MYCN expression. N cells derived from the NBL-W cell line (W-N) express 5-fold higher levels of MYCN mRNA and 10-fold higher levels of MYCN protein than S cells (W-S), despite having the same MYCN copy number. In an effort to identify the molecular mechanisms responsible for the disparity in steady-state MYCN levels, the rate of MYCN mRNA degradation was measured in the two subclones. The half-life of MYCN mRNA in the W-N cells was approximately 45 min compared to approximately 6 min in the W-S cells. Similarly, the half-life of another labile mRNA, c-fos, differed in W-N and W-S cells (30 min versus 15 min, respectively). The turnover of labile mRNAs is thought to be mediated by the interactions of trans-acting factors with AU-rich elements within the 3' untranslated region. RNA UV cross-linking assays using W-N cell lysate demonstrated abundant quantities of a protein, 40 kDa in size (p40), that bound specifically to AU-rich elements within the MYCN and c-fos 3' untranslated region. However, p40 was barely detectable in W-S cells. Our studies suggest that p40 may play a role in determining neuroblastoma phenotype by regulating MYCN and c-fos mRNA turnover.
authors.affiliation: Program in Tumor Cell Biology, Robert H. Lurie Cancer Center, Northwestern University Medical School, Chicago, Illinois 60611, USA.
authors.forename: D
authors.initials: D
authors.lastname: Chagnovich
authors.forename: S L
authors.initials: SL
authors.lastname: Cohn
mesh_terms: D001665:Binding Sites; D006801:Humans; D009363:Neoplasm Proteins / Q000378:metabolism*; D009447:Neuroblastoma / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D017423:Sequence Analysis, RNA; D014407:Tumor Cells, Cultured
chemical_list: D009363:Neoplasm Proteins; D016760:Proto-Oncogene Proteins c-fos; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D016601:RNA-Binding Proteins