Histone chaperone; regulates chromatin structure, transcription, mRNA 3'-end formation and genome stability; role in chromatin remodeling and nucleosome assembly; acidic intrinsically disordered NTD binds histones and controls chromatin structure; role in replication initiation, promoting origin licensing through MCM helicase loading; required for fidelity of transcriptional promoter selection through maintenance of chromatin structure; required for H3K36 trimethylation by Set2p