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Fig. 3. Spatial expression of XCL-2. (A) A posterior view of stage
12.5 embryos. Dorsal is up. Signal appears at a restricted area
ventral to blastopore. (B,C) Anterior and posterior views, respectively,
of the same stage 15 embryo. Dorsal is up. In (B), expression
is detected at the most anterior of neural plate; in (C) it shows
the same expression zone as in (A). (D) Ventral view of a late
neurula. Anterior is left. It shows the localized expression
in cement gland and proctodeum. (E) Ventral view of an early
tail-bud. Anterior is left. The expression in cement gland and
proctodeum becomes even stronger. (F) In late tail-bud stages,
expression is only detected in the cement gland. (G) A sagittal
section through a stage 15 embryo, confirming that the expression
in (B) and (C) is only localized to the mesoderm-free zone
and the ventral circumblastoporal collar. The expression zone is
highlighted with boxes. (H,I) Sagittal sections through the head
and tail of a stage 23 embryo, respectively, confirming that
the expression in (E) is only localized to cement gland and
proctodeum. a, anterior view; bl, blastopore; cg, cement gland;
mfz, mesoderm-free zone; nf, neural fold; nt, neural tube;
p, posterior view; pc, prosencephalon; pr, proctoduem; pv,
procencephalic ventricle; vbc, ventral circumblastoporal collar. |