The conserved histone chaperone Spt6 facilitates DNA replication and mediates genome instability [S1-DRIP-seq]

Histone chaperones are an important class of factors that regulate chromatin accessibility for DNA-templated processes. Spt6 is a conserved histone chaperone and key regulator of transcription and chromatin structure. However, its functions outside of these roles have been little explored. In this work, we demonstrate a role for Spt6 in DNA replication and more broadly as a regulator of genome stability. Spt6 binds the replication machinery and mutations or loss of Spt6 impair DNA replication in vivo. Additionally, spt6 mutants are sensitive to DNA replication stress inducing agents, with increased sensitivity when combined with loss of DNA replication associated factors. Furthermore, spt6 mutants have elevated levels of DNA double strand breaks and are hyper-recombinogenic. R-loops do not appear to be elevated in spt6 mutants. In total, we identify Spt6 as a regulator of genome stability, at least in part through a role for Spt6 in DNA replication. Overall design: S1-nuclease DNA-RNA hybrid IP (S1-DRIP-sq) in WT and spt6-YW samples. A RNaseH treated negative control is included for each sample. Samples were prepared in biological duplicate.