Expression of β-galactosidase driven from Prnp gene control elements in the nervous system, limbs, and skin of the developing embryo. Expression from Tg(Prnp-LacZ)E3755/Prnp^+/+ is shown between stages E11.5 to E13.5 p.c. by whole-mount staining followed by dissection or sectioning to reveal expression. At E11.5 p.c., expression is evident in the ventral region of the (A) hindbrain and (B) neural tube at the trunk level that corresponds to motor neuron (mn) columns. Expression in the ectoderm (ec) and in surrounding mesenchyme (ms) is also evident. (C) At E12.5 p.c., expression extends to the dorsal neural tube. Expression includes dorsal root ganglia (dg), dorsal and ventral roots (dr, vr) as well as ectoderm and notochord (nt). At E13.5 p.c., LacZ activity is evident in the (D) developing limbs and (E) skin. (F) At E13.5 p.c., expression is detected in the CNS, PNS and in various developing peripheral organs. (G) Externally, expression is observed in various areas of the skin. Abbreviations: ad, adrenal; al, allantois; am, amniotic membrane; ar, apical ectodermal ridges; ce, cerebellar anlage; cp, cortical plate; dg, dorsal root ganglia; dt, dorsal thalamus; ee, external ear; Fl, forelimb; gp, genital protuberance; hb, hindbrain; he, heart; hl, hindlimb; hy, hypothalamus; lu, lung; ma, mamillary area; md, medulla; me, mesencephalon; mg, mammillary gland elevation; mn, motor neuron column; nf, neural folds; nt, notochord; oc, optic cup; oe, olfactory epithelium; ov, otic vesicle; po, pons; pn, peripheral nerves; ps, primitive streak; sc, spinal cord; se, septum; sg, sympathetic ganglia; so, somites; st, sympathetic trunk; te, telencephalon; to, tongue; vi, vibrissae.; vr, ventral root; vz, ventricular zone

Expression of PrP^C in FVB mice and Syrian hamsters. Western blot analysis detects (A, C) mouse PrP^C using the RO73 polyclonal antiserum and (B) hamster PrP^C with the 3F4 monoclonal antibody. (A) Expression in entire embryos or in isolated heads and bodies (as indicated) from E8.5 p.c. to adulthood. (B) PrP^C expression in developing embryonic or neonatal Syrian hamster brains and skin. (C) PrP^C in adult mouse organs. Antisera against actin (bottom of panel A) and synaptophysin (bottom of panel B) were used as controls. Forty μg of homogenate were used per lane except for the brain homogenate from wt mouse ((A) and (C)), for which 5 μg were used. Abbreviations: E, embryonic day; Ep, epididymis; SHa, Syrian hamster; P, postnatal day.

Developmental expression of ®-galactosidase driven by Prnp gene control elements in the post-implantation embryo. LacZ expression is shown between E7.5 to E13.5 p.c. by whole-mount staining. (A, B) At E7.5 p.c., expression is observed in the deciduum (de), allantois (al) and faintly in the amniotic membrane (am). (C) At E8.0 p.c., invaginating cephalic neural folds (nf) display LacZ expression. (D, E) At E8.5 p.c., expression is upregulated in the mesencephalic (me) and hindbrain (hb) levels. Ventrally, the heart (he) and caudally, the primitive streak region (ps), also show expression. (F) At E9.5 p.c., expression shifts rostrally toward the telencephalic (te) area, and decreases in the mesencephalic (me) area. (G) Transient LacZ expression in neuroectoderm prior to neural tube closure in the posterior neural tube at E8.5 p.c. Sections 1, 2, and 3 correspond to levels 1–3 shown in panel D. (H) Rostral telencephalon (corresponding to level 1 in panel F) and (I) mesencephalon (corresponding to level 2 in panel F) at E9.5 p.c. The open anterior neuropore is visible. LacZ staining is confined to the cephalic mesenchyme (outside of the dotted lines). Abbreviations: am, amniotic membrane; de, deciduum; hb, hindbrain; he, heart; me, mesencephalon; nf, neural folds; nt, notochord; oc, optic cup; ov, otic vesicle; ps, primitive streak; sc, spinal cord; se, septum; sg, sympathetic ganglia; so, somites; te, telencephalon.

Expression of the Prnp-LacZ transgene in the adult brain coincides with endogenous PrP^C expression. Expression of the LacZ marker is shown in higher-magnification images of the neocortex (A–B), hippocampal dentate gyrus (C), cerebellar cortex and deep cerebellar nuclei (H). Expression of the LacZ marker is presented in coronal sections of the brain at the levels of the hippocampus (E) and cerebellum (F). Immunohistochemistry using RO73 polyclonal antiserum is shown for comparison in the neocortex (B) and hippocampus (D). Arrows in both (C) and (H) indicate scattered glial cells expressing LacZ. Abbreviations: bs, brainstem; cc, corpus callosum; cx, neocortex; dc, deep cerebellar nuclei; dg, dentate gyrus; ec, entorhinal cortex; gl, granule cell layer; hl, hilus of dentate gyrus; hp, hippocampus; ml, molecular layer; pl, Purkinje cell layer; th, thalamus; wm, white matter tracts; Roman numerals I–VI in (A) refer to the layers of the neocortex.