Figure 7 .

Mechanisms by which genome instability occurs in replication-deficient mutants. (A) tRNA genes and replication forks are clustered in proximity to Ty retrotransposons. The transcription machinery creates obstacles for replication fork progression and could lead to DSB formation and resection to the repeated elements. (B) Secondary structure formation involving repeated Ty retrotransposons (arrows) on the lagging strand causes replication fork stalling, subsequent replisome dissociation, and the formation of double stranded breaks (DSBs). (C) Failure to resolve termination structures at converging replication forks that flank Ty retrotransposons is a potential source of DSBs.