Sundberg Sofie C, Granseth Björn
Department of Clinical and Experimental Medicine, Linköping University, Sweden.
Department of Clinical and Experimental Medicine, Linköping University, Sweden.
Neurosci Lett. 2018 May 14;675:36-40. doi: 10.1016/j.neulet.2018.03.053. Epub 2018 Mar 23.
Genetically modified mouse strains that express Cre-recombinase in specific neuronal sub-populations have become widely used tools for investigating neuronal function. The Ntsr1-Cre GN220 mouse expresses this enzyme in corticothalamic neurons in layer 6 of cerebral cortex. We observed that about 7% of Cre-expressing cells in the primary visual cortex are found within the white matter bordering layer 6. By using the immunohistochemical marker for layer 6 neurons, Forkhead box protein 2 (FoxP2), and fluorescently conjugated latex beads injected into the dorsal lateral geniculate nucleus, we show that about half of these cells are similar to and could belong to the layer 6 corticothalamic neuron population. The other half seems to be a distinct white matter (WM) neuron sub-population that we estimate to constitute 2-4% of the total cortical Cre-expressing population. Staining for the neuronal marker Neuronal nuclei (NeuN) revealed that about 15-40% of WM neurons are Cre-expressing. Thus, the potential contribution from WM neurons needs to be considered when interpreting the results from experiments using the Ntsr1-Cre GN220 mouse for investigating corticothalamic neuronal function.
在特定神经元亚群中表达Cre重组酶的转基因小鼠品系已成为研究神经元功能的广泛使用的工具。Ntsr1-Cre GN220小鼠在大脑皮层第6层的皮质丘脑神经元中表达这种酶。我们观察到，在初级视觉皮层中，约7%表达Cre的细胞位于与第6层相邻的白质内。通过使用第6层神经元的免疫组织化学标记物叉头框蛋白2（FoxP2），以及注射到背外侧膝状核的荧光共轭乳胶珠，我们发现这些细胞中约一半与第6层皮质丘脑神经元群体相似且可能属于该群体。另一半似乎是一个独特的白质（WM）神经元亚群，我们估计其占皮质Cre表达群体总数的2-4%。对神经元标记物神经元细胞核（NeuN）的染色显示，约15-40%的WM神经元表达Cre。因此，在解释使用Ntsr1-Cre GN220小鼠研究皮质丘脑神经元功能的实验结果时，需要考虑WM神经元的潜在贡献。
