Tolerance of DNA Replication Stress Is Promoted by Fumarate Through Modulation of Histone Demethylation and Enhancement of Replicative Intermediate Processing in Saccharomyces cerevisiae

摘要

Fumarase is a well-characterized TCA cycle enzyme that catalyzes the reversible conversion of fumarate to malate. In mammals, fumarase acts as a tumor suppressor, and loss-of-function mutations in the FH gene in hereditary leiomyomatosis and renal cell cancer result in the accumulation of intracellular fumarate-an inhibitor of alpha-ketoglutarate-dependent dioxygenases. Fumarase promotes DNA repair by nonhomologous end joining in mammalian cells through interaction with the histone variant H2A.Z, and inhibition of KDM2B, a H3 K36-specific histone demethylase. Here, we report that Saccharomyces cerevisiae fumarase, , acts as a response factor during DNA replication stress, and fumarate enhances survival of yeast lacking (H2A.Z in mammals). We observed that exposure to DNA replication stress led to upregulation as well as nuclear enrichment of , and raising levels of fumarate in cells via deletion of or addition of exogenous fumarate suppressed the sensitivity to DNA replication stress of Delta mutants. This suppression was independent of modulating nucleotide pool levels. Rather, our results are consistent with fumarate conferring resistance to DNA replication stress in Delta mutants by inhibiting the H3 K4-specific histone demethylase , and increasing H3 K4 methylation. Although the timing of checkpoint activation and deactivation remained largely unaffected by fumarate, sensors and mediators of the DNA replication checkpoint were required for fumarate-dependent resistance to replication stress in the Delta mutants. Together, our findings imply metabolic enzymes and metabolites aid in processing replicative intermediates by affecting chromatin modification states, thereby promoting genome integrity.