SeamFIG 4A-F: Development of the seam through embryonic and post-embryonic stages.
A, B, E are epifluorescent images of transgenic animals expressing the ajm-1::GFP reporter in epithelial cells. (Strain source: H. Yu and P. W. Sternberg.) C, D, F are epifluorescence images of transgenic animals expressing the F09D12.15::GFP reporter in the seam. A-F Original magnification, 600x (Strain source: The Genome BC C. elegans gene expression consortium; McKay et al., 2004.)
A. Lima-bean-stage embryo, left lateral view. Ten embryonic seam cells (labeled H0-T) are bounded by hypodermis on the dorsal side and hypodermis and P cells on the ventral side.
Cell labeled V5 is the mother of the V5 blast cell at this stage.
B. Three-fold-stage embryo, right lateral view. Lateral hypodermal cells change their shape during to elongation, becoming narrower and longer due to contraction of circumferential actin bundles.
C. Early-L1-stage animal, left oblique view. Ten seam cells make a string of cells on each side (right-side seam cells are seen as faint). The anteriormost seam cell, H0, ends at the border of hyp 5-hyp 6 (left inset, arrow), whereas the posteriormost seam cell, T, ends at the border of hyp 7-hyp 8 (right inset, arrow)
D. Later-stage-L1 animal, left lateral view. All seam cells except for H1, H2, T and H0, have duplicated. The identity of the mother cell is marked underneath its descendants. Their anterior daughters will fuse with the major hypodermis hyp 7.
E. Early-L2-stage animal when all seam cells, except for H0 and T, have duplicated, left lateral view. The identity of the original stem cell is given underneath its descendants. H0 does not divide. Anterior daughter of V5p is in the process of generating the posterior deirid (arrow).
F. Late-L2-stage animal, left lateral view. After the fusion of their sisters with hyp 7, 15 newly born seam cells elongate over their sisters to make contact with one another (arrow shows V3ppp extending towards V4pap).
See also SeamFIG 4G-I.
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