Distribution of OL-protocadherin in axon fibers in the developing chick nervous system.
OL-protocadherin (OL-pc) is a homophilic cell adhesion molecule that belongs to the cadherin gene superfamily. We cloned and characterized the chicken homologue of OL-pc and examined its expression pattern in chick embryos mainly from embryonic day (E) 3.5 to E6.5. The structure of chick OL-pc was found to be essentially the same as that of mammalian OL-pc's except for some small deletions and insertions in the amino acid sequence. OL-pc protein was detected prominently along developing axonal fibers in the brain and also in the peripheral nervous system. In addition, it was detected in some mesenchymal cells and in the embryonic ectoderm of the mandible and limb bud. In the spinal cord, OL-pc was specifically expressed in motor neurons, and the protein was distributed along motor nerves. Motor nerves merged gradually with sensory nerves showing negative/faint OL-pc expression, but their fibers remained separated as small bundles in the nerves. Interestingly, OL-pc-positive motor nerves such as those to the sternocoracoideus became segregated from OL-pc-faint/weak motor nerves at the plexus region. Moreover, OL-pc was distributed along the path of the branchial nerves. These results suggest that OL-pc might play some roles in axon navigation such as in axon elongation, selective fasciculation, and pathfinding in the early stage of neural development.
Nakao
Shinsuke
S
RIKEN Center for Developmental Biology, 2-2-3 Minatojima-Minamimachi, Chuou-ku Kobe 650-0047, Japan.
Uemura
Masato
M
Aoki
Eiko
E
Suzuki
Shintaro T
ST
Takeichi
Masatoshi
M
Hirano
Shinji
S
D000595:Amino Acid Sequence; D000818:Animals; D001369:Axons / Q000378:metabolism*; D015153:Blotting, Western / Q000379:methods; D002038:Bungarotoxins / Q000378:metabolism; D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D015816:Cell Adhesion Molecules, Neuronal / Q000378:metabolism; D002642:Chick Embryo; D002645:Chickens; D058969:Contactin 2; D005455:Fluorescent Antibody Technique / Q000379:methods; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D017403:In Situ Hybridization / Q000379:methods; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D008967:Molecular Biology / Q000379:methods; D009218:Myosins / Q000378:metabolism; D009420:Nervous System / Q000033:anatomy & histology / Q000254:growth & development / Q000378:metabolism*; D016900:Neurofilament Proteins / Q000378:metabolism; D000091363:Protocadherins; D015053:Zygote
D002038:Bungarotoxins; D015820:Cadherins; D015816:Cell Adhesion Molecules, Neuronal; C548675:Cntn2 protein, mouse; D058969:Contactin 2; D016900:Neurofilament Proteins; C117277:Pcdh10 protein, mouse; D000091363:Protocadherins; D019950:Mitogen-Activated Protein Kinase 1; D009218:Myosins