Molecular mapping of the origin of postnatal spinal cord ependymal cells: evidence that adult ependymal cells are derived from Nkx6.1+ ventral neural progenitor cells.
Recent studies have suggested that the ependymal cells lining the central canal of postnatal spinal cord possess certain properties of neural stem cells. However, the embryonic origin and developmental potential of the postnatal spinal cord ependymal cells remain to be defined. In this report, we investigated the developmental origin of postnatal spinal ependymal cells by studying the dynamic expression of several neural progenitor genes that are initially expressed in distinct domains of neuroepithelium in young embryos. At later stages of development, as the ventricular zone of the embryonic spinal cord is reduced, expression of Nkx6.1 progenitor gene is constantly detected in ependymal cells throughout chick and mouse development. Expression of other neural progenitor genes that lie either dorsal or ventral to the Nkx6.1+ domain is gradually decreased and eventually disappeared. These results suggest that the remaining neuroepithelial cells at later stages of animal life are derived from the Nkx6.1+ ventral neuroepithelial cells. Expression of Nkx6.1 in the remaining neuroepithelium is closely associated with, and regulated by, Shh expression in the floor plate. In addition, we suggested that the Nkx6.1+ ependymal cells in adult mouse spinal cords may retain the proliferative property of neural stem cells.
Fu
Hui
H
Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Kentucky 40292, USA.
Qi
Yingchuan
Y
Tan
Min
M
Cai
Jun
J
Hu
Xuemei
X
Liu
Zijing
Z
Jensen
Jan
J
Qiu
Mengsheng
M
D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D002642:Chick Embryo; D004805:Ependyma / Q000166:cytology / Q000196:embryology* / Q000254:growth & development* / Q000378:metabolism; D005136:Eye Proteins; D005455:Fluorescent Antibody Technique; D018507:Gene Expression Regulation, Developmental; D053823:Hedgehog Proteins; D000090322:Homeobox Protein Nkx-2.2; D018398:Homeodomain Proteins / Q000378:metabolism*; D017403:In Situ Hybridization; D051379:Mice; D009419:Nerve Tissue Proteins / Q000378:metabolism; D000076104:Oligodendrocyte Transcription Factor 2; D000071841:PAX6 Transcription Factor; D051763:PAX7 Transcription Factor; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins; D013116:Spinal Cord; D013234:Stem Cells / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D029961:Zebrafish Proteins
D051792:Basic Helix-Loop-Helix Proteins; D005136:Eye Proteins; D053823:Hedgehog Proteins; D000090322:Homeobox Protein Nkx-2.2; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D000076104:Oligodendrocyte Transcription Factor 2; D000071841:PAX6 Transcription Factor; D051763:PAX7 Transcription Factor; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D029961:Zebrafish Proteins; C491328:Nkx6-1 protein, mouse; C512773:Olig2 protein, mouse; C000605730:PAX6 protein, human; C000605732:Pax6 protein, mouse; C497322:Pax7 protein, mouse; C509239:SHH protein, human