Selective expression of the small GTPase RhoB in the early developing mouse lens

This report describes the expression and distribution pattern of RhoB GTPas e in the developing mouse lens. RhoB expression was confirmed by sequencing an reverse transcriptase-polymerase chain reaction-generated DNA fragment of RhoB. Immunohistochemical analysis of RhoB revealed expression in the le ns vesicle (both anterior and posterior vesicle) at embryonic day (E) 11.5, and in the epithelium and primary fibers of the E14.5 lens. Compared with the neonatal stage (day 1), where RhoB is detected in the entire lens (epit helium, primary, and secondary fibers), expression of this protein is restr icted to the epithelial and outer cortical secondary fibers in postnatal le nses (from day 7 to day18). Interestingly, in E11.5 and E14.5 lenses, RhoB is localized predominantly in the lens, but not detectable in the retina, c ornea, or other ocular tissues. RhoB expression appears to be down-regulate d in the postnatal lens with concomitant up-regulation in the retina and co rnea, compared with earlier stages of development (eyes of E 11.5, E14.5, a nd neonatal mice). This study reveals the selective expression of RhoB in t he lens during early eye development and suggests a potential role for this small GTPase in cytoskeletal reorganization associated with lens epithelia l cell elongation and differentiation. (C) 2001 Wiley-Liss, Inc.