Abstract
The mechanisms through which the oncoprotein c-Myc initiates locus-specific gene amplification are not understood. When analysing the initiation mechanism of c-Myc-dependent amplification of the mouse ribonucleotide reductase R2 (R2) gene, we observe c-Myc-dependent initiation of illegitimate DNA replication of the R2 gene. We demonstrate multiple simultaneous c-Myc-induced R2 replication forks, whereas R2 normally replicates with a single fork. In contrast, cyclin C replicates with only a single replication fork irrespective of c-Myc deregulation. In addition to de novo replication forks, c-Myc also initiates bi-allelic replication of R2, abrogating its normal mono-allelic replication pattern. Moreover, several chromosomal regions also display c-Myc-induced illegitimate replication profiles. Thus, c-Myc can act as an illegitimate replication-licensing factor that promotes de novo replication initiation and illegitimate replication timing that adversely impacts upon genomic stability.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Alleles
-
Animals
-
Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
-
Basic-Leucine Zipper Transcription Factors
-
Bromodeoxyuridine / analysis
-
Cell Cycle / genetics
-
Cells, Cultured
-
Chromosome Banding
-
Chromosomes / genetics
-
Chromosomes / ultrastructure
-
Cyclin C
-
Cyclins / genetics
-
DNA Replication / physiology
-
DNA-Binding Proteins / chemistry
-
Dimerization
-
Electrophoresis, Gel, Two-Dimensional
-
Electrophoretic Mobility Shift Assay
-
Gene Amplification
-
Gene Expression Regulation
-
Genes, myc
-
Hematopoietic Stem Cells / drug effects
-
Hematopoietic Stem Cells / metabolism
-
Humans
-
Mice
-
Mitotic Index
-
Protein Binding
-
Proto-Oncogene Proteins c-myc / chemistry
-
Proto-Oncogene Proteins c-myc / physiology*
-
Recombinant Fusion Proteins / chemistry
-
Recombinant Fusion Proteins / physiology
-
Recombination, Genetic / genetics
-
Recombination, Genetic / physiology*
-
Regulatory Sequences, Nucleic Acid
-
Ribonucleoside Diphosphate Reductase / genetics*
-
Transcription Factors*
-
Transfection
Substances
-
Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
-
Basic-Leucine Zipper Transcription Factors
-
CCNC protein, human
-
Ccnc protein, mouse
-
Cyclin C
-
Cyclins
-
DNA-Binding Proteins
-
MAX protein, human
-
Myc associated factor X
-
Proto-Oncogene Proteins c-myc
-
Recombinant Fusion Proteins
-
Transcription Factors
-
Max protein, mouse
-
ribonucleotide reductase M2
-
Ribonucleoside Diphosphate Reductase
-
Bromodeoxyuridine