Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
Anat Rec (Hoboken). 2013 Sep;296(9):1364-82. doi: 10.1002/ar.22733. Epub 2013 Jul 31.
The neurons in the olfactory bulb originate from molecularly defined and spatially distinct proliferative regions. Glutamatergic projection neurons are generated during the embryonic period in the local ventricular zone of the olfactory bulb, a territory in the dorsal telencephalon in which the transcription factor Pax6 is expressed. Some cells in this zone also express Tbr1, a marker of glutamatergic neurons. By contrast, embryonic olfactory bulb interneurons are derived from Gsx2 expressing cells in the dorsal lateral ganglionic eminence of the ventral telencephalon, and from progenitors outside the dorsal lateral ganglionic eminence, including the olfactory bulb neuroepithelium. Postnatally, interneurons arise from the subventricular zone of the lateral ventricle, although the rostral migratory stream and the olfactory bulb also appear to serve as a source of neurons. Transcription factors are crucial to generate all classes of neurons and glia in the olfactory bulb, both during development and adulthood. In this article, we discuss and propose models on how the spatial and temporal regulation of transcription factor expression controls the self-renewal, proliferation and cell fate of neural stem cells and progenitors, which finally leads to the generation of distinct functional subtypes of neurons in the developing and adult olfactory bulb.
嗅球中的神经元来源于分子定义和空间上不同的增殖区域。谷氨酸能投射神经元在胚胎期于嗅球局部脑室区产生，该区域是背侧端脑的一个区域，其中转录因子 Pax6 表达。该区域中的一些细胞也表达 Tbr1，这是谷氨酸能神经元的标志物。相比之下，胚胎嗅球中间神经元来源于腹侧端脑背外侧神经节隆起中的 Gsx2 表达细胞，以及背外侧神经节隆起以外的祖细胞，包括嗅球神经上皮。出生后，中间神经元起源于侧脑室的室下区，尽管前脑导水管周围灰质和嗅球似乎也可以作为神经元的来源。转录因子对于在嗅球中产生所有神经元和神经胶质类型至关重要，无论是在发育过程中还是成年期。在本文中，我们讨论并提出了模型，说明转录因子表达的时空调节如何控制神经干细胞和祖细胞的自我更新、增殖和细胞命运，最终导致发育中和成年嗅球中不同功能亚型神经元的产生。
