Abstract: Silence information regulator 2（Sir2）family is a group of conserved deacetylases，widely existed in organisms from archaea to mammals，and characterized by NAD+-dependent deacetylase and ADP-ribosyltransferase activities. Sir2 plays an important role in various life progresses，such as chromatin silence，gene regulation，metabolic regulation，life span of cells and so on. Through its deacetylase activity and/or interaction with other proteins，Sir2 can regulate chromatin structure or modify transcription related factors，thus regulating the transcriptional process. This article emphasizes on the progress of Sir2-dependent regulation of gene transcription.

Key words: Silence information regulator 2, Deacetylase, Chromatin, Transcriptional regulation, Parasite