Differential expression of Hoxa-2 protein along the dorsal-ventral axis of the developing and adult mouse spinal cord.
We have used synthetic oligopeptides derived from the coding sequence of the murine Hoxa-2 protein to produce polyclonal antibodies that specifically recognize the Hoxa-2 recombinant protein. Immunohistochemical studies reveal a distinct pattern of spatial and temporal expression of Hoxa-2 protein within the mouse spinal cord which is concomitant with the cytoarchitectural changes occurring in the developing cord. Hoxa-2 protein is predominantly detected in the nuclei of cells in the ventral mantle region of 10-day-old mouse embryos. Islet-1, a marker for motor neurons was also shown to be co-localized with Hoxa-2 in nuclei of cells in this region. As development progresses from 10-days to 14-days of gestation, Hoxa-2 protein expression gradually extends to the dorsal regions of the mantle layer. The Hoxa-2 protein expression pattern changes at 16-days of embryonic development with strong expression visible throughout the dorsal mantle layer. In 18-day-old and adult mouse spinal cords, Hoxa-2 protein was expressed predominantly by cells of the dorsal horn and only by a few cells of the ventral horn. Double labeling studies with an antibody against glial fibrillary acidic protein (GFAP, an astrocyte-specific intermediate filament protein) showed that within the adult spinal cord, astrocytes rarely expressed the Hoxa-2 protein. However, Hoxa-2 and GFAP double-labeled astrocytes were found in the neopallial cultures, although not all astrocytes expressed Hoxa-2. Hoxa-2 expressing oligodendrocyte progenitor cells were also identified after double-labeling with O4 and Hoxa-2 antibodies; although cells in this lineage that have begun to develop a more extensive array of cytoplasmic processes were less likely to be Hoxa-2 positive. The early pattern of Hoxa-2 protein expression across transverse sections of the neural tube is temporally and spatially modified as each major class of neuron is generated. This congruence in the expression of the Hoxa-2 protein and the generation of neurons in the cord suggests that the Hoxa-2 protein may contribute to dorsal-ventral patterning and/or to the specification of neuronal phenotype. Dev Dyn 1999;216:201-217.
Hao
Z
Z
Laboratory of Molecular Biology, College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Canada.
Yeung
J
J
Wolf
L
L
Doucette
R
R
Nazarali
A
A
D000367:Age Factors; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D001253:Astrocytes / Q000378:metabolism*; D015153:Blotting, Western; D002467:Cell Nucleus / Q000737:chemistry; D002478:Cells, Cultured; D003593:Cytoplasm / Q000737:chemistry; D005801:Genes, Homeobox / Q000235:genetics; D018398:Homeodomain Proteins / Q000032:analysis* / Q000235:genetics; D007150:Immunohistochemistry; D051379:Mice; D009474:Neurons / Q000378:metabolism*; D009836:Oligodendroglia / Q000378:metabolism*; D013116:Spinal Cord / Q000196:embryology* / Q000378:metabolism*; D013904:Thoracic Vertebrae / Q000196:embryology*
D000911:Antibodies, Monoclonal; D018398:Homeodomain Proteins