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発表内容

Title:
Random walk-like migratory behaviors of GABAergic interneurons in the developing mouse cortex

Fujio Murakami
Professor, Graduate School of Frontier Biosciences, Osaka University

Abstract:
It is well documented that cortical interneurons originate from the basal forebrain and tangentially migrate to the cortex. However, relatively little is known about their migration after their arrival at the cortex. To elucidate the route and mode of intracortical interneuron migration, we performed real-time analysis by utilizing glutamate decarboxylase 67-green fluorescence protein knock-in mice and an electroporation-based gene transfer of dsRed into the ganglionic eminence (GE) of mouse embryos. In coronal slices, ventrolateral-to-dorsomedial migration predominantly occurs in the lower-intermediate zone. Observations of the marginal zone (MZ) or the ventricular zone in flat-mounted cortex from the pial or the ventricular surface, respectively, reveal that that the interneurons tangentially migrate in all directions. Medial GE-derived interneurons visualized bydsRed electroporation exhibit a diverse range of behaviors in terms of the rate and direction of migration. Curiously, a predominant population of these neurons repeatedly change their direction of migration in an unpredictable manner. Trajectories of migration vary from one neuron to another. The migration of individual cells lasts for long periods, sometimes up to two days. Theoretical analyses reveal that these behaviors can be modeled by a random walk. Furthermore, MZ cells migrate from the cortical subventricular zone to the cortical plate, transiently accumulating in the MZ . These results suggest that MGE-derived cortical interneurons, once arriving at the MZ, are released from regulation by guidance cues and initiate random walk movement, which potentially contributes to their dispersion throughout the cortex.

References:
Daisuke H Tanaka, Sakae Mikami, Takashi Nagasawa, Jun-Ichi Miyazaki, Kazunori Nakajima, Fujio Murakami (2010)  CXCR4 Is Required for Proper Regional and Laminar Distribution of Cortical Somatostatin-, Calretinin-, and Neuropeptide Y-Expressing GABAergic Interneurons.   Cereb Cortex [Epub ahead of print] PMID: 20200107