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Fig. 5. Spatial expression of E59 (FGFR-Al), G62, and E30 transcripts
in tailbud Xenopus embryos. Whole-mount in situ hybridizations
were performed on albino Xenopus embryos using digoxigenin-labeled
antisense RNA probes. Hybridization signals were visualized as alkaline
phosphatase chromogenic reaction products. A: Lateral view of a stage
29/30 embryo stained for E59 mRNA expression. E59 transcripts are
detected mainly in the brain, pronephros, and somites. Note also the high
levels of expression in unsegmented somitogenic mesoderm (sm). 9:
Close-up view of A at higher magnification showing details of E59 mRNA
expression in the anterior half of the embryo. Extensive expression is
seen in the fore-, mid-, and hindbrain (fb, mb, and hb). The otic vesicle
(ov) is indicated as a reference point for the posterior limit of the E59
expression in the hindbrain. Staining is also associated with visceral
arches (arrows), the pronephros (pn), and the pronephric duct (pd). C:
Lateral view of a stage 29/30 embryo stained for G62 mRNA. Similar to
E59, G62 transcripts are mainly detected in the brain, pronephroi, and
somites. No expression was detected in unsegmented somitogenic mesoderm
as with E59. D: Close-up view of C at higher magnification. In the
brain, expression of G62 transcripts is seen predominantly in the eye
vesicle (ev), midbrain (mb), and hindbrain (hb). The midbrain/hindbrain
junction (j) is devoid of G62 transcripts. Other areas of expression include
the pronephros (pn), the pronephric duct (pd), and the tissues in the
region of the liver rudiment (Ir). Faint expression is also seen in the
visceral arches (arrows). E: Lateral view of a stage 28 embryo stained for
E30 mRNA expression. Extensive expression of E30 transcripts is seen
in the brain, visceral arches, and at lower levels in somites. F: Close-up
view of E at higher magnification to illustrate staining of the olfactory
placode (op), the wall of the otic vesicle (ov), the forebrain (fb), and
visceral arches (arrows). All embryos were rendered transparent with
Murray's clear prior to hybridization. Anterior ends of embryos are oriented
to the left. Scale bars: A = 288 pm; B = 144 pm; C, E = 225 km;
D, F = 112.5 pm. |
