Sca-1 expression pattern in the mouse limbal epithelium and its association with cell cycle

Stem Cell Antigen-1 or Sca-1 is a cell surface receptor protein commonly used to detect adult murine haematopoietic stem cell population. Outside the haematopoietic system Sca-1 is similarly expressed in stem and progenitor cells in a wide variety of tissues and organs such as skeletal muscle, mammary gland, prostate, heart, liver and dermis. Thus Sca-1 has become a candidate marker in the search of tissue specific stem cells. The maintenance of a healthy corneal epithelium is achieved by a unique population of stem cell located in the limbal epithelial region. This limbal epithelium mainly contains limbal epithelial stem cells and its immediate progenitor early transient amplifying cells (e-TAC) which have self renewal capacity. As stem cells in other organs have been identified by their expression of Sca-1, in our study we wanted to determine whether this antigen could be present in the limbal epithelial region which contains stem cell population by using immunofluorescence through flow cytometric analysis of Sca-1 and its association with the cell cycle.