Expression data of pmr1∆ mutants

The yeast PMR1 (ATP2C1) gene codes for the eukaryotic prototype of a high affinity P-type ATPase required for Ca2+/Mn2+ transport into the Golgi. Cells lacking PMR1 exhibit multiple genetic interactions with genes involved in DNA recombination and replication, a fact that is not yet understood. We find that deletion of PMR1 causes a delay in DNA replication initiation, progression and G2/M transition and induces the transcriptional up-regulation of genes involved in cell cycle regulation, including CLB5 and SWE1. Interestingly, pmr1∆ clb5∆ double mutants exhibit a dramatic delay in DNA replication and increased DNA breakage, while endoreplication and the formation of multi-nucleated, giant yeast is observed in pmr1∆ swe1∆ cells. Because these phenotypes can be attributed to impeded Mn2+-pump function, we provide a model in which Mn2+ interferes with Mg2+ in the nucleus, and vice versa, Mg2+ interferes with Mn2+ in the Golgi. Consequently, cell cycle progression is challenged by aberrant catalytic activities of enzymes involved in replication and protein glycosylation. Three repeats of pmr1∆ mutant. Total RNA levels in pmr1∆ mutants were analyzed and compared to the wild type submitted to the GEO database under the accession number GSE29334 (C. Gonzalez-Aguilera and A. Aguilera), which has been superseded by GSE56702.