1. Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
2. Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
* Present address: 3-12-69-2-233, Yada, Higashi-ku, Nagoya 461-0040, Japan
In vertebrates, the proximal and distal sensory ganglia of the branchial nerves are derived from neural crest cells (NCCs) and placodes, respectively. We previously reported that in Hoxa3 knockout mouse embryos, NCCs and placode-derived cells of the glossopharyngeal nerve were defective in their migration. In this report, to determine the cell-type origin for this Hoxa3 knockout phenotype, we blocked the expression of the gene with antisense morpholino oligonucleotides (MO) specifically in either NCCs/neural tube or placodal cells of chicken embryos. Our results showed that HOXA3 function was required for the migration of the epibranchial placode-derived cells and that HOXA3 regulated this cell migration in both NCCs/neural tube and placodal cells. We also report that the expression pattern of chicken HOXA3 was slightly different from that of mouse Hoxa3.
Keywords: Hoxa3, branchial nerve, neural crest, placode, axon guidance, hindbrain, cell migration