Opposite replication polarity of the germ line c-myc gene in HeLa cells compared with that of two Burkitt lymphoma cell lines.

AUTOR(ES)

Leffak, M

RESUMO

To study the cell type specificity of the direction of replication of the human c-myc genes and the relationship of replication polarity to transcriptional activity, we analyzed the directions of replication of the c-myc genes in two Burkitt lymphoma cell lines, CA46 and ST486, and in HeLa cells. On the basis of in vitro runoff replication of forks initiated in intact cells, we found that transcribed c-myc genes in the germ line configuration in HeLa cells were replicated in the direction of transcription from origins in the 5'-flanking DNA, while the repressed, unrearranged c-myc genes of CA46 and ST486 cells were replicated in the antitranscriptional direction. In contrast, the transcribed c-myc genes of CA46 cells were replicated in the transcriptional direction, while the translocated, amplified c-myc genes of ST486 cells showed no preferred polarity of replication. The data also provided evidence for the existence of an endogenous barrier to DNA polymerases in the flanking DNA immediately 5' to the HeLa c-myc genes.

Documentos Relacionados

• DNA replication initiates non-randomly at multiple sites near the c-myc gene in HeLa cells.
• Evidence that a triplex-forming oligodeoxyribonucleotide binds to the c-myc promoter in HeLa cells, thereby reducing c-myc mRNA levels.
• An initiation zone of chromosomal DNA replication located upstream of the c-myc gene in proliferating HeLa cells.
• c-Myc Proteolysis by the Ubiquitin-Proteasome Pathway: Stabilization of c-Myc in Burkitt's Lymphoma Cells
• Cloning and sequencing of a c-myc oncogene in a Burkitt's lymphoma cell line that is translocated to a germ line alpha switch region.