Interference with function of a homeobox gene in Xenopus embryos produces malformations of the anterior spinal cord.
XIHbox 1 is expressed in a narrow band across the cervical region of Xenopus embryos. The gene produces two related proteins: "long" and "short" XIHbox 1 homeodomain proteins. Injection of antibodies to the long XIHbox 1 protein into 1-cell embryos caused a phenotype in which the anterior spinal cord was morphologically transformed into a hindbrain-like structure. This alteration was restricted to the region normally expressing long XIHbox 1 protein. Injection of long protein mRNA disrupted segmentation and tissue organization without inhibiting cell proliferation. Injection of short protein mRNA into 1-cell embryos produced spinal cord malformations similar, but not identical, to those caused by the antibodies, suggesting antagonistic roles for long and short XIHbox 1 proteins. We immunostained tadpoles carrying extended hindbrains for N-CAM and consistently found defective organization of spinal nerves over the affected region.
Wright
C V
CV
Department of Biological Chemistry, University of California School of Medicine, Los Angeles 90024-1737.
Cho
K W
KW
Hardwicke
J
J
Collins
R H
RH
De Robertis
E M
EM
D000818:Animals; D000906:Antibodies / Q000008:administration & dosage; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D004625:Embryo, Nonmammalian / Q000002:abnormalities* / Q000032:analysis; D005801:Genes, Homeobox; D018398:Homeodomain Proteins; D008845:Microinjections; D009024:Morphogenesis; D009154:Mutation; D009363:Neoplasm Proteins; D010641:Phenotype; D012249:Rhombencephalon / Q000002:abnormalities / Q000196:embryology; D013116:Spinal Cord / Q000002:abnormalities* / Q000032:analysis / Q000196:embryology; D013126:Spinal Nerve Roots / Q000002:abnormalities; D013194:Staining and Labeling; D029867:Xenopus Proteins; D014982:Xenopus laevis / Q000196:embryology / Q000235:genetics*
D000906:Antibodies; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; C492048:Hoxa7 protein, Xenopus; D009363:Neoplasm Proteins; D029867:Xenopus Proteins