FIGURE 4.

High frequency of Ty1 his3AI retromobility was independent of DNA-binding protein-mediated replication fork arrest. Autoradiograms of two-dimensional agarose gels of replication intermediates from the rDNA Ter region of chromosome XII showing that in the wild-type strain (WT) DNA replication fork were arrested at the Ter sites (black arrow), the arrest was abolished in tof1Δ and csm3Δ strains (panels marked tof1Δ and csm3Δ, respectively); in contrast, in the rrm3Δ strain replication fork arrest occurs at Ter sites is enhanced over that of the WT strain (rrm3Δ) and fork arrest occurred at 3 other locations (open arrows); in both rrm3Δ tof1Δ and rrm3Δ csm3Δ strains the fork arrest was partially restored at Ter and elsewhere; in the dia2Δ strain the replication fork arrest at Ter sites was unaffected; the dia2Δtof1Δ and dia2Δcsm3Δ cells did not show any restoration of fork arrest at the Ter sites as contrasted with rrm3Δtof1Δ and rrm3Δcsm3Δ strains.