Division of Histology, Department of Oral Growth and Development, School of Dentistry, Health Sciences University of Hokkaido, Ishikari-Tobetsu 061-0293, Japan.
J Mol Histol. 2010 Oct;41(4-5):205-14. doi: 10.1007/s10735-010-9280-8. Epub 2010 Jul 29.
Members of the Six gene family are expressed in various tissues including sensory organs, such as the inner ear and olfactory epithelium. We examined the expression of Six1 and Six4 mRNAs in mouse taste buds by using in situ hybridization. Six1 was detected immunohistochemically in the nuclei of taste bud cells, in a subset of type-II cells, as shown by double-immunolabeling with anti-Six1 together with anti-PLCβ2 or anti-IP(3)R3 antibodies. Six1-immunoreactive (IR) nuclei appeared at embryonic day 17.5 in the dorsal epithelium, and in the trench wall epithelium of circumvallate papillae at postnatal day 5. At this stage, Six1-IR nuclei were observed in all newly-formed type-II cells. During postnatal development, type-II cells increased in number, but those with Six1-IR nuclei showed no apparent increase. After transection of the bilateral glossopharyngeal nerve, type-II cells gradually disappeared; but some of them remained in the epithelium even at 11-17 days post-transection. The remaining type-II cells showed Six1-immunoreactivity. At 24 days after nerve transection, regenerating type-II cells appeared; and strong Six1-immunoreactivity was observed in them. Also, enhanced green fluorescent protein-immunoreactivity and β-galactosidase-immunoreactivity, which were indicators for Six1 transcripts and Six4 transcripts, respectively, overlapped. These results suggest that Six1 and Six4 genes are expressed in the taste bud cells, in newly formed or surviving type-II cells.
Six 基因家族的成员在包括感觉器官在内的各种组织中表达，例如内耳和嗅上皮。我们通过原位杂交检查了 Six1 和 Six4 mRNA 在小鼠味蕾中的表达。通过与抗 PLCβ2 或抗 IP(3)R3 抗体一起进行双重免疫标记，在味觉细胞的细胞核中检测到 Six1 的免疫组织化学，在一部分 II 型细胞中检测到。Six1-免疫反应性（IR）核在胚胎第 17.5 天出现在背侧上皮中，并且在出生后第 5 天的环咽乳头的沟上皮中出现。在这个阶段，所有新形成的 II 型细胞中都观察到 Six1-IR 核。在出生后发育过程中，II 型细胞数量增加，但具有 Six1-IR 核的细胞没有明显增加。在切断双侧舌咽神经后，II 型细胞逐渐消失；但其中一些在神经切断后 11-17 天仍存在于上皮中。剩余的 II 型细胞表现出 Six1-免疫反应性。在神经切断后 24 天，再生的 II 型细胞出现；并且在它们中观察到强烈的 Six1-免疫反应性。此外，增强型绿色荧光蛋白免疫反应性和β-半乳糖苷酶免疫反应性，分别是 Six1 转录物和 Six4 转录物的指标，重叠。这些结果表明 Six1 和 Six4 基因在味觉细胞中表达，在新形成或存活的 II 型细胞中表达。
