title: Spatiotemporal regulation of keratin 5 and 17 in the axolotl limb.
abstract: BACKGROUND
  Amphibians have greater regeneration capability than higher vertebrates. They can regenerate their limbs after an amputation. As a limb is regenerated, a regeneration-specific epithelium called the apical epithelial cap (AEC) is induced. The AEC is an essential structure for limb regeneration. Despite the importance of the AEC, molecular marker genes have not been well studied at the molecular level.
  
  
  RESULTS
  In the present study, keratin5 (KRT5) and KRT17 were investigated in an axolotl-regenerating limb. KRT5 and KRT17 were expressed in a regenerating limb but down-regulated in a differentiating limb. KRT5 showed characteristic regulation in a regenerating blastema. KRT5 was suppressed in the basal layer of the AEC. This KRT5 suppression was correlated to the blastema differentiation and nerve presence. Simple skin wounding could also upregulate both KRT5 and KRT17 gene expression. But these genes were suppressed within a shorter time than in limb regeneration.
  
  
  CONCLUSIONS
  The KRT5 and KRT17 gene profile can be a useful marker gene to investigate AEC in limb regeneration.
authors: Okayama University, Research Core for Interdisciplinary Sciences (RCIS), Okayama, Japan.
authors: Miyuki
authors: M
authors: Moriyasu
authors: Aki
authors: A
authors: Makanae
authors: Akira
authors: A
authors: Satoh
mesh_terms: D000558:Ambystoma mexicanum / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D004848:Epithelium / Q000378:metabolism; D005121:Extremities / Q000502:physiology*; D005786:Gene Expression Regulation / Q000235:genetics / Q000502:physiology*; D006652:Histological Techniques; D017403:In Situ Hybridization; D053537:Keratin-17 / Q000378:metabolism*; D053555:Keratin-5 / Q000378:metabolism*; D012038:Regeneration / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D053537:Keratin-17; D053555:Keratin-5