Patterning of the neural ectoderm of Xenopus laevis by the amino-terminal product of hedgehog autoproteolytic cleavage.
The patterns of embryonic expression and the activities of Xenopus members of the hedgehog gene family are suggestive of role in neural induction and patterning. We report that these hedgehog polypeptides undergo autoproteolytic cleavage. Injection into embryos of mRNAs encoding Xenopus banded-hedgehog (X-bhh) or the amino-terminal domain (N) demonstrates that the direct inductive activities of X-bhh are encoded by N. In addition, both N and X-bhh pattern neural tissue by elevating expression of anterior neural genes. Unexpectedly, an internal deletion of X-bhh (delta N-C) was found to block the activity of X-bhh and N in explants and to reduce dorsoanterior structures in embryos. As elevated hedgehog activity increases the expression of anterior neural genes, and as delta N-C reduces dorsoanterior structures, these complementary data support a role for hedgehog in neural induction and anteroposterior patterning.
Lai
C J
CJ
Department of Pharmacology, University of Washington School of Medicine, Seattle 98195, USA.
Ekker
S C
SC
Beachy
P A
PA
Moon
R T
RT
D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D004475:Ectoderm / Q000502:physiology; D004627:Embryonic Induction / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D053823:Hedgehog Proteins; D008969:Molecular Sequence Data; D009420:Nervous System / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology; D010447:Peptide Hydrolases / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011506:Proteins / Q000378:metabolism / Q000502:physiology*; D015534:Trans-Activators; D029867:Xenopus Proteins; D014982:Xenopus laevis
D017931:DNA Primers; D053823:Hedgehog Proteins; C509232:IHH protein, Xenopus; D010446:Peptide Fragments; D011506:Proteins; D015534:Trans-Activators; D029867:Xenopus Proteins; D010447:Peptide Hydrolases