The miRNA-processing enzyme dicer is essential for the morphogenesis and maintenance of hair follicles

Curr Biol. 2006 May 23;16(10):1041-9. doi: 10.1016/j.cub.2006.04.005. Epub 2006 May 11.


The discovery that microRNAs (miRNAs) play important roles in regulating gene expression via posttranscriptional repression has revealed a previously unsuspected mechanism controlling development and progenitor-cell function (reviewed in ); however, little is known of miRNA functions in mammalian organogenesis. Processing of miRNAs and their assembly into the RNA-induced silencing (RISC) complex requires the essential multifunctional enzyme Dicer . We found that Dicer mRNA and multiple miRNAs are expressed in mouse skin, suggesting roles in skin- and hair-follicle biology. In newborn mice carrying an epidermal-specific Dicer deletion, hair follicles were stunted and hypoproliferative. Hair-shaft and inner-root-sheath differentiation was initiated, but the mutant hair follicles were misoriented and expression of the key signaling molecules Shh and Notch1 was lost by postnatal day 7. At this stage, hair-follicle dermal papillae were observed to evaginate, forming highly unusual structures within the basal epidermis. Normal hair shafts were not produced in the Dicer mutant, and the follicles lacked stem cell markers and degenerated. In contrast to decreased follicular proliferation, the epidermis became hyperproliferative. These results reveal critical roles for Dicer in the skin and implicate miRNAs in key aspects of epidermal and hair-follicle development and function.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Hair / growth & development
  • Hair Follicle / cytology
  • Hair Follicle / growth & development*
  • Hair Follicle / physiology
  • Hedgehog Proteins
  • Keratin-15
  • Keratins / metabolism
  • Mice
  • MicroRNAs / metabolism
  • Morphogenesis
  • Oncogene Proteins / metabolism
  • Receptor, Notch1 / metabolism
  • Ribonuclease III / genetics
  • Ribonuclease III / physiology*
  • Sequence Deletion
  • Skin / growth & development
  • Skin / metabolism
  • Skin Abnormalities / genetics
  • Stem Cells / metabolism
  • Trans-Activators / metabolism
  • Zinc Finger Protein GLI1


  • Hedgehog Proteins
  • Keratin-15
  • Krt15 protein, mouse
  • MicroRNAs
  • Notch1 protein, mouse
  • Oncogene Proteins
  • Receptor, Notch1
  • Shh protein, mouse
  • Trans-Activators
  • Zinc Finger Protein GLI1
  • Keratins
  • Ribonuclease III

Associated data

  • GEO/GSE4723