microRNAs are short (~22 nucleotides) RNA molecules which have been shown to play a critical role in post-translational control of gene expression.  Primary microRNAs (pri-miRNA) is transcribed by RNA pol II.  These pri-miRNAs may contain up to six miRNA precursors.  This double stranded RNA contains hairpin structures which are recognized by DGCR8 which with Drosha forms the microprocessor complex. DGCR8 aligns the pri-miRNA with Drosha’s RNase III domain which cleaves the pri-miRNA into a pre-miRNA hairpin.  The pre-miRNA is then exported from the nucleus using Exportin-5.

Once in the cytoplasm Dicer cleaves the pre-miRNA into a duplex ~22 nucleotides in length.  One strand is preferential incorporated into the RNA-Induced Silencing Complex (RISC) to act as a guide strand allowing the RISC complex to act in a target specific manner.  The RISC ‘s RNA cleavage activity is provided by members of the Argonaut family of proteins.  Ago-2 can act specifically to cleave target RNA, while other family members appear to recruit additional proteins to the RISC complex.  Studies have shown that multiple proteins may be incorporated into the RISC including, TARDBP, PACT, FMRP and Tudor-SN.

All microRNA Antibodies, Lysates, Proteins and RNAi