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Wnt Signal Transduction in the Early Embryo by MikeJenny

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									Wnt Signal Transduction in the Early
              Embryo
                                                                         Figure 1: Wnt expression in whole
                                       HB
            a                                                            mounts and cryosections of head
E 8.5


           b
           ba1                                                           from E8.5 to E11.5
                                                            ba1
                                                                     ba1: first branchial arch, ot:
                                  CNC a                           b
                                     LT
                                       a FB                        b otocyst, FB: Forebrain, LT: Lamina
                 a                                                   Terminalis, HB: Hindbrain, MB/HB:
                 a
E9.5




                                                      ba1            Midbrain-Hindbrain Junction, OE:
           b                 ot
          ba1
            b                                                        Oral Epithelium, CNC: Cranial
                           HB                                        Neural Crest, TG: Trigeminal
                                        a        HB               b
                                            a                     b Ganglion
                                       FB
                 a
E 10.5




                 ab               LT
                  b                                     LT               ba1
                                                eye
         ba1 c
             c              MB/HB
                                                            TG
                                        a                        b                  c
                                            a                        b              c
                                        FB
                                                            LT
E 11.5




                      aa          LT                                           OE
               eye   bb
                           MB/HB                ot
                                                        eye
                      c
                      c
                                        a                        b                  c
                                            a                    b                  c
 Wnt Signal Transduction in Later Stages of the Embryo
                  a            CC
                                                                                    OE                 OE
                  ba
  E 12.5
                   cb                             CF             CF
                   dc          LT
                    d                                            HT
                  ee

                          MB                 MO                       MO ot          OP                OP
                                     a
                                     a                  b
                                                        b              cc             d
                                                                                      d                 e
                                                                                                        e
                                    CC                                               OL
                     a
                     a                                                        eye              ns
  E 13.5




                     b
                     b                                      CE
                     c
                     c                                                CC                      T
                     d
                      d        MB                 MB                            T
                     e
                     e
                           MB/HB             MB/HB
                                 a                      b             cc              d                 ee
                            CC a                        b                              d
                  a
                                                  CC                                OL            ns
                    a                                       eye
  E 14.5




                  bb                                                                                   R
                  cc                              MB                                  CE
                  dd
                    e      MB
                  b                           P/MB
                                    SE                 SE                             d      nt
                                     a
                                     a                  b
                                                        b              c
                                                                       c                 d              e
                                                                                                        e
               a a
                 b
                 b                                     HF
  E 16.5




                                    TS
                                              a                       MO       R      b
                          PC                                                                  HF
                                                                                b
                                         a
Figure 4: TCF-LEF/LacZ expression in the Wnt signaling reporter in whole mounts and
cryosections of head from E12.5 to E16.5; ba1: first branchial arch, ot: otocyst, ns: nasal septum,
nt: neural tube, hf: hair follicle; see Table 1 for expanded key
Key Structures that Process Wnt Signaling in Later Stages
 E12.5   Future Cerebral Cortex (CC), Lamina Terminalis (LT), Midbrain (MB), Medulla Oblongata
         (MO), Choroidal Fissure (CF), Hypothalamus (HT), Olfactory Epithelium (OE), Otic Placode
         (OP)

 E13.5   Lamina Terminalis (LT), Midbrain-Hindbrain Junction (MB/HB), Midbrain (MB), Future
         Cerebral Cortex (CC), Corneal Epithelium (CE), Future Olfactory Lobe (OL), Tongue (T)


 E14.5   Future Cerebral Cortex (CC), Midbrain (MB), Surface Ectoderm (SE), Pons-Midbrain
         Junction (P/MB), Future Olfactory Lobe (OL), Corneal Epithelium (CE), Retina (R)


 E16.5   Hair Follicle (HF), Medulla Oblongata (MO), Primitive Cerebellum (PC), Thalamus (TS),
         Retina (R)

 Table 1: Key structures in later stages of development that process Wnt
 signal reporter.
Figure 3: Wnt signal reporter expression in the dermis at E13.5, E14.5 and in
the hair follicles at E16.5.
Cranial Neural Crest Cells Process Wnt Signal
                                     d


                   ba1
                              Beta-gal                       Beta-gal
           brain              AP2α                           AP2α
                    ba1
 E 8.5

                          c              ba1                   ba1

                                                                    c              d




Figure 4: Double immunostaining in the head for AP-2 alpha (red), a neural crest
       3:
marker, and beta-gal (green).
Dermal Progenitors Process Wnt Signal
         Dermo1          Dermo1         Dermo1 TCF-Lef-LacZ
E 9.5

             ba1
                          ba1                                   ba1
                                                                      A

                          ba1                             ba1
E 10.5




                   ba1

                                                                      B
E 11.5




                                                                      C
         Figure 5:
         Figure 4: Whole mounts and cryosections of head
         probed with Dermo1, a dermal progenitor marker.
         Dermal progenitors prior to E11.5 process Wnt
         signaling in the branchial arches (ba). Sections A-C
         show Wnt signal in TCF-LEF cryosections of the
         head.
Figure 6: In the conditional absence of beta-catenin in the En1 lineage, loss of
TCF/LEF-LacZ signal is seen in the mid-hindbrain region, branchial arches (ba1), and
frontonasal mass (fnm). TCF/LEF-LacZ signal is preserved in non-En1 lineages.

								
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