Lack of correlation between N-myc and MAX expression in neuroblastoma tumors and in cell lines: implication for N-myc-MAX complex formation.
Detectable levels of MAX messenger RNA were found in a set of human neuroblastoma tumors and established cell lines. MAX mRNA levels were independent of tumor stage and N-myc genomic amplification. By contrast, N-myc mRNA transcripts were detectable only in tumors with amplification of N-myc gene and in cell lines. Analysis by reverse transcriptase polymerase chain reaction and hybridization to specific oligodeoxynucleotide probes revealed approximately equal amounts of two MAX transcripts in all cases analyzed. Immunoprecipitations with a specific antibody to MAX detected two proteins of M(r) 21,000 and 22,000 in approximately equal amounts in all neuroblastoma lines regardless of N-myc amplification and/or expression. On the other hand, protein binding to the myc DNA consensus sequence correlated with N-myc expression in neuroblastoma cells. Thus, N-myc expression might be a limiting factor in the formation of the N-myc-MAX heterodimer in neuroblastomas.
Raschella
G
G
ENEA (Ente Nuove Tecnologie Energia e Ambiente) CRE Casaccia, Division of Molecular Biology, Rome, Italy.
Romeo
A
A
Negroni
A
A
Pucci
S
S
Dominici
C
C
Castello
M A
MA
Bevilacqua
P
P
Felsani
A
A
Calabretta
B
B
D000595:Amino Acid Sequence; D001483:Base Sequence; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D050976:Basic-Leucine Zipper Transcription Factors; D015139:Blotting, Southern; D002460:Cell Line; D016384:Consensus Sequence; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004273:DNA, Neoplasm / Q000032:analysis / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000378:metabolism*; D015870:Gene Expression; D016259:Genes, myc; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009447:Neuroblastoma / Q000235:genetics* / Q000378:metabolism*; D009838:Oligodeoxyribonucleotides / Q000378:metabolism*; D016133:Polymerase Chain Reaction / Q000379:methods; D016271:Proto-Oncogene Proteins c-myc / Q000096:biosynthesis / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D050976:Basic-Leucine Zipper Transcription Factors; D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; C499330:MAX protein, human; C067850:Myc associated factor X; D009838:Oligodeoxyribonucleotides; D016271:Proto-Oncogene Proteins c-myc; D014157:Transcription Factors; D004247:DNA