Imaging X-gal Labeled Stem Cells in Skin Tissue

Office Of The Director, Nih

Investigators

Abstract

Correlative transmission electron microscopy (TEM) has been performed to complement optical imaging of mouse skin tissue containing a low density of stem cells labeled with the reporter gene beta-gal. These cells produce a clearly visible indigo staining in thick paraffin sections after treatment with the reagent X-gal. After optical microscopy, the paraffin was removed from regions of skin containing one or more labeled cells and the pieces of tissue were re-embedded in plastic. The blocks were then ultramicrotomed to yield serial thin sections that were stained with uranyl acetate and lead citrate, and subsequently imaged at a beam voltage of 120 kV in an energy-filtering transmission electron microscope. By carefully correlating the light and electron micrographs and by examination of the ultrastructure, it was possible to identify the labeled stem cells as keratinocytes.