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. Author manuscript; available in PMC: 2009 Nov 4.
Published in final edited form as: Fertil Steril. 2007 Sep 4;89(6):1771–1776. doi: 10.1016/j.fertnstert.2007.05.074

Figure 1.

Figure 1

MicroRNA Cellular Pathway. The gene for the miRNA is transcribed by RNA polymerase II into a single strand of RNA. This single strand folds into a hair-pin like structure and becomes the double stranded primary miRNA or “Pri-miRNA”. The hairpin like structure is subsequently cleaved in the nucleus by Drosha forming the pre-miRNA The pre-miRNA then enters the cytoplasm via the protein channel Exportin, where it is cleaved into a small piece of double stranded RNA by the enzyme Dicer. The double stranded small RNA then separates into single strands with one strand being degraded and the other strand forming a complex with Argonaute proteins. This newly formed protein/nucleic acid complex is called a RNA induced silencing complex or RISC. These complexes then either bind mRNA with exact complementarity leading to cleavage of the mRNA by the RISC or they bind with partial complementarity leading to repression of translation.