Transitin, a nestin-like intermediate filament protein, mediates cortical localization and the lateral transport of Numb in mitotic avian neuroepithelial cells.
Neuroepithelium is an apicobasally polarized tissue that contains neural stem cells and gives rise to neurons and glial cells of the central nervous system. The cleavage orientation of neural stem cells is thought to be important for asymmetric segregation of fate-determinants, such as Numb. Here, we show that an intermediate filament protein, transitin, colocalizes with Numb in the cell cortex of mitotic neuroepithelial cells, and that transitin anchors Numb via a physical interaction. Detailed immunohistological and time-lapse analyses reveal that basal Numb-transitin complexes shift laterally during mitosis, allowing asymmetric segregation of Numb-transitin to one of the daughter cells, even when the cell cleavage plane is perpendicular to the ventricular surface. In addition, RNA interference (RNAi) knockdown of the transitin gene reveals its involvement in neurogenesis. These results indicate that transitin has important roles in determining the intracellular localization of Numb, which regulates neurogenesis in the developing nervous system of avian embryos.
Wakamatsu
Yoshio
Y
Department of Developmental Neurobiology, Tohoku University, Graduate School of Medicine, Seiryo-machi 2-1, Aoba-ku, Sendai, Miyagi 980-8575, Japan.
Nakamura
Noriko
N
Lee
Ju-Ahng
JA
Cole
Gregory J
GJ
Osumi
Noriko
N
D000818:Animals; D002454:Cell Differentiation; D002462:Cell Membrane / Q000378:metabolism; D002642:Chick Embryo; D018507:Gene Expression Regulation, Developmental; D007381:Intermediate Filament Proteins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008938:Mitosis; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D064231:Nestin; D046569:Neuroepithelial Cells / Q000166:cytology* / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D034622:RNA Interference
D007381:Intermediate Filament Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D064231:Nestin