HDAC 1 , a histone deacetylase , forms a complex with Hus 1 and Rad 9 , two G2 / M checkpoint Rad proteins . ^^^ Furthermore , HDAC 1 and Hus 1 were found to exist in a complex with Rad 9 , a known Hus 1 interacting factor . ^^^
Deletion of either SIN 3 or RPD 3 in rad 9 or mec 1 checkpoint mutant strains suppresses sensitivity to replication blocks and DNA damage resulting from Cdc 9 ligase deficiency and UV irradiation . ^^^