The Drosha-DGCR8 microprocessor complex is required for microRNA (miRNA) biogenesis. DGCR8 (DiGeorge Syndrome Critical Region 8) recognizes the RNA substrate, whereas Drosha functions as the endonuclease. DGCR8, which contains two double-stranded RNA (dsRNA)-binding domains, interacts with the pri-miRNA and functions as the molecular anchor that measures the distance from the ds-RNA-ssRNA junction and directs Drosha cleavage 11bp away (Han J et al, 2006). The efficiency of Drosha cleavage increases in the presence of heme and promotes the formation of highly ordered DGCR8 structures upon binding to RNA (Faller et al, 2010).
