Meis1 contributes to dorsal-ventral patterning in the developing retina. (A, B, I, J) mRNA in situ hybridization (ISH) for the dorsal marker tbx5 (A, B) and the ventral marker vax2 (I, J) in 15-hpf wild-type and meis1 morphant (meis1MO) embryos. Black dotted lines outline the optic vesicle. Arrows indicate tbx5 expression in the presumptive dorsal retina. Purple dotted lines indicate the domain of vax2 expression. All views are dorsal with anterior left. (C, D, F, G, K, L, N, O) mRNA ISH for dorsal genes tbx5 (C, D) and efnb2a (F, G), and ventral genes vax2 (K, L) and ephb2 (N, O) in dissected, flat-mounted eyes from 28-hpf wild-type and meis1 morphant embryos. Arrows indicate the approximate limit of the gene expression domain. (E, H, M, P) The domains of gene expression were quantified by determining a 360° profile of in situ staining intensity and graphing the radial position at which gene expression intensity falls to the halfway point between its minimum and maximum values. The nmax/2 and tmax/2 values are given as the mean radial position in degrees ± one standard deviation. Asterisks indicate regions in which there are statistically significant differences in axial identity between wild type (WT) and meis1 morphants as determined by an unpaired, two-tailed t-test using a P-value of 0.01 as a cutoff for significance. Representative dissected eyes are shown. Scale bars = 50 μm.
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