Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA.
Cereb Cortex. 2012 Oct;22(10):2313-21. doi: 10.1093/cercor/bhr308. Epub 2011 Nov 7.
A group of 5 genes, OCC1, testican-1, testican-2, 5-HT1B, and 5-HT2A, are selectively expressed in layer 4 (4C of Brodmann) of striate cortex (visual area V1) of both Old World macaques and New World marmoset monkeys. The expression of these genes is activity dependent, as expression is reduced after blocking retinal activity. Surprisingly, the pronounced expression pattern has not been found in rodents or carnivores. Thus, these genes may be highly expressed in V1 of some but perhaps not all primates. Here, we compared the gene expression in members of 3 major branches of primate evolution: prosimians, New World monkeys, and Old World monkeys. Although the expression pattern of 5-HT1B was well conserved, those of the other genes varied from the least distinct in prosimian galagos to successively more in New World owl monkeys, marmosets, squirrel monkeys, and Old World macaque monkeys. In owl monkeys, the expression of 5-HT2A was significantly reduced by monocular tetrodotoxin injection, while those of OCC1 and 5-HT1B were not. Thus, we propose that early primates had low levels of expression and higher levels emerged with anthropoid primates and became further enhanced in the Old World catarrhine monkeys that are more closely related to humans.
一组 5 个基因，即 OCC1、testican-1、testican-2、5-HT1B 和 5-HT2A，选择性地在旧大陆猴和新世界狨猴的纹状皮层（视觉区域 V1）的第 4 层（Brodmann 的 4C）表达。这些基因的表达是活性依赖性的，因为在阻断视网膜活性后表达会降低。令人惊讶的是，这种明显的表达模式在啮齿动物或食肉动物中并未发现。因此，这些基因可能在某些但不是所有灵长类动物的 V1 中高度表达。在这里，我们比较了灵长类动物进化的 3 个主要分支（原猴类、新世界猴和旧世界猴）中的成员的基因表达。尽管 5-HT1B 的表达模式得到了很好的保守，但其他基因的表达模式从原猴类的夜猴中差异最小，到新世界的吼猴、狨猴、松鼠猴和旧世界的猕猴中依次增加。在吼猴中，单眼肉毒杆菌毒素注射显著降低了 5-HT2A 的表达，而 OCC1 和 5-HT1B 的表达则没有。因此，我们提出，早期的灵长类动物的表达水平较低，随着类人猿灵长类动物的出现，表达水平提高，并在与人类关系更密切的旧大陆食肉类猴中进一步增强。
