| |
Figure 5. Impairment of eye development upon Dhcr7 overexpression in Xenopus. a-j: Microinjection of mouse Dhcr7 (mDhcr7, 2 ng) into one blastomere of two-cell-stage embryos. In combination, 200 pg of beta -galactosidase mRNA was injected as linage tracer (blue staining). a, c, e: Anterior view (dorsal up). b, b rdquo , d, d rdquo , f, f rdquo : Lateral view (dorsal up). b', d', f': Frontal view (dorsal up). g, h, i, j: Dorsal view (anterior down). b rdquo ', d rdquo ': Horizontal sections. f rdquo ', g', h', i', i rdquo : Transversal sections. a-h': WMISH analysis of Xrx1/Xen2/Xkrox20 (a-b rdquo lsquo ), Xsix3 (c-d rdquo '), Xn-tubulin (e-f rdquo rsquo ), Xgsh1 (g, g'), and Xnkx2.2 (h, h') expression. i-j: Eye phenotype. a, c: Early expression of Xrx1 (e) and Xsix3 is mildly expanded (a and c, compare the injected and non-injected sides). The expression of Xkrox20 (r3 and r5) and Xen2 (mhb) show a slight reduction, especially in the 5th rhombomere (Xkrox20). b, b', b rdquo , d, d', d rdquo : Reduced expression of Xrx1 (b-b rdquo ; 43%, n = 30) and Xsix3 (d-d rdquo ; 60%, n = 30) at tailbud stage. e: Suppression of the early expression of Xn-tubulin in the trigeminal placode (36%, n = 25). f-f rdquo ': Reduction of Xn-tubulin staining in the cranial placodes at tailbud stage (48%, n = 40; red arrowheads in f rdquo ). f rdquo ': Expansion of the neural tube on the injected side (dashes). g, g': Expansion of Xgsh1 expression (47%, n = 32). h, h': Slight expansion of Xnkx2.2 expression (33%, n = 30). i, j: Small eyes (55%, n = 200) and/or pigmented optic stalks (30%, n = 200; red arrowhead in j) induced by mDhcr7 injection. The overall patterning of the injected side's retina is not affected (i' and i rdquo ). cp, cranial placode; cs, control side; is, injected side; le, lens; mhb, midbrain-hindbrain boundary; r3, rhombomere 3; r5, rhombomere 5; rpe, retinal pigmented epithelium; tp, trigeminal placode. |
