Figures & data
Figure 1 miRNA-33: A key regulator of metabolic pathways. Transcriptional activation of Srebp-2 or Srebp-1 by low sterol levels or LXR ligands/insulin, respectively, induces the co-transcription of miR-33a and miR-33b from their host genes. These miRNAs simultaneously inhibit the expression of several targets involved in cholesterol transport, fatty acid oxidation and glucose metabolism by binding to complementary regions in their 3′UTRs. Upper right part: General view of microRNA biogenesis. miRNAs are transcribed in the nucleus as long primary transcripts (pri-miRNAs) and processed by Drosha to produce stem-loop-structured precursors (pre-miRNA), which are then exported to the cytoplasm via Exportin 5. Once in the cytoplasm, they are further processed by Dicer to generate a 22-bp miRNA duplex. One strand of the duplex is incorporated in the RNA-induced silencing complex (RISC complex) containing Ago proteins. These mature miRNAs bind to partially complementary sites in the 3′UTR of target genes to promote translational repression or mRNA degradation.
