Representative images of MTAP immunolabelling in human (A–F) and rat (G–L) ocular tissues.

<p>In formalin-fixed, paraffin-embedded human eyes, positive labelling for MTAP is discernible in cells located in the corneal epithelium (A) and trabecular meshwork/Schlemm’s canal (B). In the retina, MTAP labelling is associated with astrocytes (arrow) and Müller cell somas (inset) and processes (C). Verification of MTAP expression by Müller cells was obtained by double-labelling immunofluorescence of MTAP (red) with the Müller cell marker glutamine synthetase (Glut Syn; green; D–F). In formalin-fixed, paraffin-embedded rat eyes positive labelling for MTAP is similarly detectable in corneal epithelial cells (G). Interestingly, in eyes fixed in Davidson’s solution, which affords superior morphological preservation, MTAP expression is strongly detected within the membranes of corneal epithelial cells (H). In the retina (I), ONH (J) and ON (K), MTAP labelling is principally localised to astrocytes. The pattern of immunoreactivity displays marked similarity to GFAP, as illustrated in (L). Scale bar: A, D–L = 15 µm; B, C = 30 µm. TM, trabecular meshwork; SC, Schlemm’s canal; GCL, ganglion cell layer; IPL, inner plexiform layer; INL, inner nuclear layer; ONH, optic nerve head.