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. Author manuscript; available in PMC: 2012 Aug 1.
Published in final edited form as: Curr Opin Genet Dev. 2011 May 16;21(4):504–510. doi: 10.1016/j.gde.2011.04.010

Figure 1.

Figure 1

Control of transcription and miRNA biogenesis by TGF-β/BMP signaling. At the core of this pathway, ligand binding to Type I/II heterodimeric receptors induces phosphorylation and nuclear translocation of SMAD transcription factors, which directly regulate the expression of protein-coding and miRNA genes. Mammalian SMAD proteins can also bind to the double-stranded stems of certain pri-miRNAs that bear CAGAC motifs, and promote their cleavage by the RNase III enzyme Drosha and its dsRBD partner DGCR8. This enhances the production of CAGAC-bearing pre-miRNAs, which are exported to the cytoplasm, cleaved by Dicer, and loaded into Argonaute (Ago) complexes to repress target genes.