Probable acetyltransferase required for the establishment of sister chromatid cohesion and couple the processes of cohesion and DNA replication to ensure that only sister chromatids become paired together. In contrast to the structural cohesins, the deposition and establishment factors are required only during S phase. Acts by acetylating the cohesin complex component SMC3 (By similarity). Belongs to the acetyltransferase family. ECO subfamily.