Figure 5.

Dynamics of association of the β-globin origin of replication with the nuclear matrix during the cell cycle of HeLa cells. (A) Schematic representation of the positions of the probes from the human β-globin locus (filled boxes). (B) Aliquots of matrix-attached DNA isolated from HeLa cells synchronized at the indicated stages of the cell cycle were dot-blotted and hybridized with DNA probes in vitro labeled with [³²P]dCTP. For determination of relative abundance the blots were rehybridized with genomic DNA. The autoradiographs were scanned and quantified and the ratios of probes to genomic DNA were calculated and presented in arbitrary units, assuming the early G₁ ratio as 1.0. Shaded columns, relative abundance of the control probe C1; filled columns, relative abundance of the β-globin replicator probe; white columns, relative abundance of the control probe C2. The results are means of five independent experiments and the standard deviations are shown with error bars.