XB-IMG-136078
Xenbase Image ID: 136078
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Figure 4 Spatial distribution of Xnot transcripts during early development. Xnot expression was analyzed by the whole-mount in situ
procedure using albino embryos. (A) Vegetal view of stage 10.5 embryos. The dorsal lip is at the top. Note the intense staining just
above the dorsal lip and the equatorial staining well above the blastopore lip (arrow). (B) Close-up of stage 10.5 embryo. The sharply
delimited staining of Xnot is apparent above the blastopore lip in the prenotochordal territory. The staining does not extend all the way
to the lip (arrow) as with other organizer-specific genes (Cho et al. 1991; Dirksen and Jamrich 1992; Ruiz i Altaba and Jessell 1992;
Taira et al. 1992). (C) Dorsal view of stage 12 embryos. The equatorial expression is no longer present. Xnot is found only along the
dorsal midline in the region that will give rise to the notochord. Anterior is at the top. (D) Close-up of a stage 12 embryo demonstrating
the gradient of expression at the anterior end and the sharp termination of expression at the blastopore. Anterior is at the top. (E) Stage
16 embryo. Xnot expression extends from the anterior (top) to the posterior along the dorsal midline, with the strongest expression in
the posterior. Two new spots of Xnot expression appear on either side of the neural plate. (F) Stage 23 embryos. Xnot is expressed only
in the posterior part of the notochord and floor plate along the body axis. In the anterior region, the two spots of Xnot expression have
almost converged as the neural plate folds up. Anterior is at the top. (Left embryo) Dorsal is at left; (middle embryo) dorsal view; (right
embryo) dorsal is at right. (G) Stage 30 embryos. Only the most posterior tip of the body axis (the tailbud, t) contains Xnot transcripts.
In the anterior region, the two spots of Xnot expression have converged in the epiphysis (e), the precursor of the pineal body. Faint
expression in other regions of the brain is also apparent. Image published in: von Dassow G et al. (1993) Copyright © 1993. Image reproduced on with permission of the Publisher, Cold Spring Harbor Laboratory Press. This is an Open Access article.
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