text: The molecular mechanism of RNAa is not fully understood.  Similar to RNAi, it has been shown that mammalian RNAa requires members of the Ago clade of Argonaute proteins, particularly Ago2, but possesses kinetics distinct from RNAi. In contrast to RNAi, promoter-targeted saRNAs induce prolonged activation of gene expression associated with epigenetic changes. It is currently suggested that saRNAs are first loaded and processed by an Ago protein to form an Ago-RNA complex which is then guided by the RNA to its promoter target. The target can be a non-coding transcript overlapping the promoter or the chromosomal DNA. The RNA-loaded Ago then recruits other proteins such as RHA, also known as nuclear DNA helicase II, and CTR9 to form an RNA-induced transcriptional activation (RITA) complex. RITA can directly interacts with RNAP II to stimulate transcription initiation and productive transcription elongation which is related to increased ubiquitination of H2B.