Cohesion establishment and maintenance are carried out by proteins that modify 
the activity of Cohesin, an essential complex that holds sister chromatids 
together. Constituents of the replication fork, such as the DNA polymerase 
alpha-binding protein Ctf4, contribute to cohesion in ways that are poorly 
understood. To identify additional cohesion components, we analyzed a ctf4Delta 
synthetic lethal screen performed on microarrays. We focused on a subset of 
ctf4Delta-interacting genes with genetic instability of their own. Our analyses 
revealed that 17 previously studied genes are also necessary for the maintenance 
of robust association of sisters in metaphase. Among these were subunits of the 
MRX complex, which forms a molecular structure similar to Cohesin. Further 
investigation indicated that the MRX complex did not contribute to metaphase 
cohesion independent of Cohesin, although an additional role may be contributed 
by XRS2. In general, results from the screen indicated a sister chromatid 
cohesion role for a specific subset of genes that function in DNA replication 
and repair. This subset is particularly enriched for genes that support the 
S-phase checkpoint. We suggest that these genes promote and protect a chromatin 
environment conducive to robust cohesion.