Abellán Antonio, Legaz Isabel, Vernier Baptiste, Rétaux Sylvie, Medina Loreta
Laboratory of Brain Development and Evolution, Department of Experimental Medicine, Faculty of Medicine, University of Lleida, Institut of Biomedical Research of Lleida (IRBLLEIDA), 25008 Lleida, Spain.
J Comp Neurol. 2009 Sep 20;516(3):166-86. doi: 10.1002/cne.22102.
We compared the combinatorial expression patterns of several LIM domain-containing regulatory genes in the ventrolateral pallium of mouse and chicken, in order to identify the homologues of the ventral pallial amygdala and other olfactory structures in birds. Lmo3, Lmo4, Lhx2, and Lhx9 showed comparable expression patterns in the telencephalon of mouse and chicken, which allowed distinction of the ventrolateral pallium and, particularly, the ventral pallial amygdala and entorhinal cortex. Lmo3 was expressed in most of the ventrolateral pallium in both species, including, in chicken, the piriform cortex and dorsal ventricular ridge (mesopallium, nidopallium, and arcopallium) and, in mouse, the piriform cortex, most of the claustral complex, and the pallial amygdala. Lhx9 was differentially expressed in the ventral pallium, where it was restricted to its rostral (olfactory bulb) and caudal (amygdalar and entorhinal) poles. In the caudal pole, expression of Lhx9 overlapped that of its paralog Lhx2. According to these expression patterns, the chicken ventral pallial amygdala appears to include the caudal dorsolateral pallium, the caudal nidopallium, and the whole arcopallium, and each one relates to a distinct ventricular sector. Finally, the combinatorial expression patterns of Lmo3, Lhx9, and Lmo4 distinguished four distinct subdivisions in the superficial, olfactorecipient area of the chicken ventral pallium, which appear comparable to the piriform, entorhinal, amygdalopiriform, and amygdalar cortices of mammals. The results are discussed in the context of the two existing, opposite views on the homology of the dorsal ventricular ridge of sauropsids and in terms of the evolution of pallial derivatives.
我们比较了小鼠和鸡腹侧 pallium 中几种含 LIM 结构域的调控基因的组合表达模式，以确定鸟类腹侧 pallial 杏仁核和其他嗅觉结构的同源物。Lmo3、Lmo4、Lhx2 和 Lhx9 在小鼠和鸡的端脑中表现出可比的表达模式，这使得能够区分腹侧 pallium，特别是腹侧 pallial 杏仁核和内嗅皮层。Lmo3 在两个物种的大部分腹侧 pallium 中表达，在鸡中包括梨状皮层和背侧脑室嵴（中脑 pallium、巢 pallium 和弓状 pallium），在小鼠中包括梨状皮层、大部分屏状核复合体和 pallial 杏仁核。Lhx9 在腹侧 pallium 中差异表达，局限于其前端（嗅球）和后端（杏仁核和内嗅）极。在后端极，Lhx9 的表达与其旁系同源物 Lhx2 的表达重叠。根据这些表达模式，鸡腹侧 pallial 杏仁核似乎包括尾侧背外侧 pallium、尾侧巢 pallium 和整个弓状 pallium，并且每个都与一个不同的脑室区域相关。最后，Lmo3、Lhx9 和 Lmo4 的组合表达模式在鸡腹侧 pallium 的浅层嗅觉接受区域区分出四个不同的亚区，这些亚区似乎与哺乳动物的梨状、内嗅、杏仁梨状和杏仁核皮层相当。在关于蜥形纲动物背侧脑室嵴同源性的两种现有相反观点的背景下，以及根据 pallial 衍生物的进化，对结果进行了讨论。
