Matrix Remodelling Associated Protein 8 (MXRA8)

Limitrin cDNA was obtained using a subtractive hybridization procedure designed to identify molecules responsible for blood-brain barrier function. The gene product is expressed significantly in mouse brain and primary murine astrocytes and is distributed in the plasma membrane. Immunohistochemical studies using confocal and electron microscopy clearly demonstrated highly polarized localization in astroglial endfeet in the perivascular region and under the pia mater in vivo. Limitrin is expressed in the spinal cord and in many areas of the brain, but not in the median eminence or subfornical organ (the circumventricular organs), where the blood-brain barrier is lacking. Limitrin is physically and functionally associated with the blood-brain barrier, implying that this protein may be useful as a diagnostic tool of barrier integrity.