The stabilization and processing of stalled replication forks is required to 
maintain genome integrity in all organisms. In an effort to identify novel 
proteins that might be involved in stabilizing stalled replication forks, 
Saccharomyces cerevisiae mutant wss1Delta was isolated from a high-throughput 
screening of approximately 5000 deletion strains for genes involved in the 
response to continuous, low-intensity UV irradiation. Disruption of WSS1 
resulted in synergistic increases in UV sensitivity with null mutants of genes 
involved in recombination (RAD52) and cell cycle control (RAD9 and RAD24). WSS1 
was also found to interact genetically with SGS1, TOP3, SRS2 and CTF4, which are 
involved in recombination, repair of replication forks and the establishment of 
sister chromatid cohesion. A yeast two-hybrid screen identified a potential 
physical interaction between Wss1 and both Psy2 and Tof1. Genetic interactions 
were also detected between PSY2 and TOF1, as well as between each gene and RAD52 
and SRS2, and between WSS1 and TOF1. Tof1 is known to be involved in stabilizing 
stalled replication forks and our data suggest that Wss1 and Psy2 similarly 
function to stabilize or process stalled or collapsed replication forks.