Okamoto Mayumi, Shinoda Tomoyasu, Kawaue Takumi, Nagasaka Arata, Miyata Takaki
Neurosci Res. 2014 Sep;86:88-95. doi: 10.1016/j.neures.2014.10.006.
The thick outer subventricular zone (OSVZ) is characteristic of the development of human neocortex. How this region originates from the ventricular zone (VZ) is largely unknown. Recently, we showed that over-proliferation-induced acute nuclear densification and thickening of the VZ in neocortical walls of mice, which lack an OSVZ, causes reactive delamination of undifferentiated progenitors and invasion by these cells of basal areas outside the VZ. In this study, we sought to determine how VZ cells behave in non-rodent animals that have an OSVZ. A comparison of mid-embryonic mice and ferrets revealed: (1) the VZ is thicker and more pseudostratified in ferrets. (2) The soma and nuclei of VZ cells were horizontally and apicobasally denser in ferrets. (3) Individual endfeet were also denser on the apical (ventricular) surface in ferrets. (4) In ferrets, apicalward nucleokinesis was less directional, whereas basalward nucleokinesis was more directional; consequently, the nuclear density in the periventricular space (within 16 μm of the apical surface) was smaller in ferrets than in mice, despite the nuclear densification seen basally in ferrets. These results suggest that species-specific differences in nucleokinesis strategies may have evolved in close association with the magnitudes and patterns of nuclear stratification in the VZ.
厚的外侧脑室下区（OSVZ）是人类新皮质发育的特征。该区域如何从脑室区（VZ）起源在很大程度上尚不清楚。最近，我们发现，在缺乏OSVZ的小鼠新皮质壁中，过度增殖诱导VZ急性核致密化和增厚，导致未分化祖细胞发生反应性分层，并使这些细胞侵入VZ外的基底区域。在本研究中，我们试图确定VZ细胞在具有OSVZ的非啮齿动物中的行为方式。对胚胎中期小鼠和雪貂的比较显示：（1）雪貂的VZ更厚且假复层化程度更高。（2）雪貂VZ细胞的胞体和细胞核在水平方向和顶-基方向上更致密。（3）雪貂单个终足在顶端（脑室）表面也更致密。（4）在雪貂中，向顶核运动的方向性较小，而向基核运动的方向性较大；因此，尽管雪貂在基底处可见核致密化，但雪貂脑室周围空间（顶端表面16μm范围内）的核密度小于小鼠。这些结果表明，核运动策略的物种特异性差异可能与VZ中核分层的程度和模式密切相关而进化形成。
