FIG. 4.
Mutant MYOC is not secreted and accumulates in the iridorcorneal angle. (A and B) Immunohistochemical labeling of eyes from Myoc+/+ mice did not reveal a detectable signal in the iridocorneal angle. Presumably, MYOC is secreted into the aqueous humor and does not accumulate in quantities great enough to be detected by immunohistochemistry. (C to F) In contrast, labeling of eyes from mice that carry one or two copies of the MyocY423H mutation revealed accumulation of MYOC in the iridocorneal angle (see merged image of fluorescence and light microscopy in panels D and F). Each bracket indicates the approximate expanse of drainage structures in the iridocorneal angle. Scale bar = 50 μm. (G) Western analysis of aqueous humor from Myoc+/+ and Myoc−/− mice revealed the presence of a MYOC-specific band in the control (Myoc+/+) mice. Consistent with the hypothesis that MYOCY423H inhibits secretion of MYOC into the aqueous humor, less secreted MYOC was detected in aqueous humor from MyocY423H/+ mice and almost no MYOC was detected in the aqueous humor of MyocY423H/Y423H mice.