| |
Fig. 3 The effects on primordial germ cell (PGC) development of
expression of mutant Germes lacking leucine zippers. Germ plasm
and PGCs (arrows) in intact (A) and GermesDLZs-expressing embryos
(B) have been visualized by whole-mount in situ hybridization
with an Xpat probe. Cross-sections through control (C) and mutant
(D) embryos demonstrate a PGC on the mesoderm–endoderm border
of the control embryo and a PGC residing deep in the endoderm
of the mutant embryo. In the PGCs of GermesDLZs-injected
embryos, the germ plasm appeared in a pool of yolk-free cytoplasm
juxtaposed to the nucleus (F), which is more characteristic for earlier
stages, while in PGCs of intact embryos, germ plasm is dispersed
between yolk platelets around the nucleus (E). We also
always noted the difference in germ plasm color in control and
mutant embryos. This may arise from the different amount of Xpat
mRNA in the PGCs, which is shown by quantitative Northern blot
analysis (Fig. 2). am, axial mesoderm; end, endoderm; lm, lateral
mesoderm; n, nucleus; not, notochord; nt, neural tube; pgc, primordial
germ cell. |
