XB-IMG-132231
Xenbase Image ID: 132231
|
FIG. 3. Fate map of the XNkx2.5 expression domain. (A and B) Three small multicellular patches within the XNkx2.5 domain of early tail-bud
stage (stage 22) embryos were microinjected with the lipophilic dye, CM-DiI. Injections were positioned in a line extending dorsally from the
posterior margin of the cement gland with site A aligned with the bottom of the eye vesicle as visible externally, site B aligned with the dorsal
border of the cement gland, and site C just off the ventral midline. (C) XNkx2.5 mRNA in a stage 22 embryos. Site A corresponded to the dorsal
border of the stage 22 Nkx2.5 domain, site B corresponded to the lateral region, and site C was near the ventral midline. (D, E, and F) The positions
of cells labeled at the three sites were examined at stage 28 in transverse Vibratome sections. (G) The data set (n 5 7 for site A, n 5 15 for site
B, and n 5 12 for site C) is summarized in the schematic (also in Table 1). Purple, yellow, and blue hatchlines represent locations of cells injected
at sites A, B, and C, respectively. Labeling of overlying ectoderm and underlying endoderm occasionally occurs and can serve as a reference point
for the injection site (white arrowheads in D and E). Note that mesodermal cells labeled by A- and B-site injections (black arrowheads in D and
E) shift ventrally between stages 22 and 28 such that cells from site A contribute to the dorsolateral edge of pericardial roof while cells from site
B contribute to dorsal mesocardium and the adjoining portion of the pericardial roof (and, infrequently, the adjoining myocardium). Site C cells,
in contrast, form myocardium and endocardium. Thus, cells within the lateral portion of the XNkx2.5 domain at stage 22 (sites A and B) shift
ventrally but do not lose XNkx2.5 expression as the sheet of cardiac cells folds to form the heart tube. Dorsal is up in all images. Abbreviations:
en, endoderm; me, mesocardium; my, myocardium; se, surface ectoderm; pc, pericardium. Image published in: Raffin M et al. (2000) Copyright © 2000. Image reproduced with permission of the Publisher, Elsevier B. V. Larger Image Printer Friendly View |