has subject area Animals Biochemical Phenomena - Signal Transduction Cell Physiological Phenomena - Cell Proliferation Cell Physiological Phenomena - Signal Transduction Growth - Cell Proliferation Mice Mutagenesis - Gene Deletion Mutation - Gene Deletion Nucleic Acids, Nucleotides, and Nucleosides - MicroRNAs Phosphatidylinositol 3-Kinases RNA - MicroRNAs RNA, Small Untranslated - MicroRNAs Skin Stem Cells