Mosaic development of the olfactory cortex with Pax6-dependent and -independent components.
The olfactory cortex is the target area of olfactory bulb axons and is suggested to be derived from neuroepithelial progenitors of various ventricular domains during development. In the present study, we examined the development of the olfactory cortex, using the newly developed monoclonal antibody (mAb) 9-4c, which recognizes reticulon 1-A and -B. The mAb labeled neuroepithelial progenitors at the pallio-subpallial boundary (PSB) and their putative descendants in the deep layers of the olfactory cortex. In the Pax6 mutant embryo, labeling at the PSB was specifically lacking, and the number of immunopositive cells in the olfactory cortex was markedly reduced. In contrast, the guidepost neurons of olfactory bulb axons, lot cells, developed relatively normally in the superficial layer of the olfactory cortex in the mutant embryo. These guidepost neurons have been recently shown to originate in the pallium and eventually guide the initial projection of olfactory bulb axons. The olfactory bulb projection in the Pax6 mutant embryo also suggested the dualistic nature of the olfactory cortex development; the initial projection of olfactory bulb axons developed relatively normally, whereas the final projection of their collateral branches was severely defective.
Hirata
Tatsumi
T
Division of Brain Function, National Institute of Genetics, Graduate University for Advanced Studies, Yata 1111, Mishima 411-8540, Japan.
Nomura
Tadashi
T
Takagi
Yoshiko
Y
Sato
Yasufumi
Y
Tomioka
Naomi
N
Fujisawa
Hajime
H
Osumi
Noriko
N
D000818:Animals; D000911:Antibodies, Monoclonal; D001369:Axons / Q000737:chemistry; D005136:Eye Proteins; D005260:Female; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics*; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D008817:Mice, Mutant Strains; D009030:Mosaicism; D009419:Nerve Tissue Proteins / Q000032:analysis / Q000235:genetics / Q000276:immunology; D009434:Neural Pathways / Q000196:embryology; D009457:Neuroglia / Q000737:chemistry; D009833:Olfactory Pathways / Q000166:cytology / Q000196:embryology*; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D011247:Pregnancy; D012333:RNA, Messenger / Q000032:analysis; D012097:Repressor Proteins
D000911:Antibodies, Monoclonal; D005136:Eye Proteins; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; C000605732:Pax6 protein, mouse; D012333:RNA, Messenger; D012097:Repressor Proteins; C489914:Rtn1 protein, mouse