Immunolocalization of a mammalian aquaporin 3 homolog in water-transporting epithelial cells in several organs of the clawed toad Xenopus laevis
Immunolocalization of a mammalian aquaporin 3 homolog in water-transporting epithelial cells in several organs of the clawed toad Xenopus laevis
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DOI：
10.1007/s00441-008-0628-2
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发表时间：
2008-08-01
影响因子：
3.6
通讯作者：
Tanaka, Shigeyasu
中科院分区：
文献类型：
--
作者：
Mochida, Hiroshi;Nakakura, Takashi;Tanaka, Shigeyasu
cDNA的核苷酸序列用于构建针对爪蟾，非洲爪蟾，即，非洲爪蟾AQP 3，哺乳动物AQP 3的同源物。非洲爪蟾水通道蛋白3的免疫定位在基底膜的腹侧皮肤，膀胱，集合管和晚期远端小管的肾脏，大肠的吸收上皮细胞的主细胞，和输卵管的纤毛上皮细胞。因此，我们将该AQP命名为基底外侧非洲爪蟾AQP 3（AQP-x3 BL）。AQP-x3 BL的标记强度在腹侧和背侧皮肤之间不同，腹侧皮肤中的主细胞的基底外侧膜显示强烈的标记，而背侧皮肤中的主细胞的基底外侧膜显示轻微的标记。AQP-x3 BL也免疫定位于小颗粒和粘液腺的皮肤分泌细胞的基底膜。由于AQP-x5是哺乳动物AQP 5的同源物，位于这些相同细胞的顶膜中，这为腺体分泌液体提供了途径。虽然Hyla AQP-h2从细胞质易位到顶端膜的Hyla膀胱精氨酸催产素（AVT），AQP-h2免疫反应在爪蟾膀胱仍然在细胞质中，几乎没有移动到顶端膜，无论AVT刺激。AQP-x3定位于基底外侧膜，即使AVT刺激的AQP-h2不易位到顶膜。这些发现为水通道蛋白在水生无尾类动物中的功能提供了新的见解。
Nucleotide sequences of cDNA were used to construct antibodies against an aquaporin (AQP) expressed in the clawed toad, Xenopus laevis, viz., Xenopus AQP3, a homolog of mammalian AQP3. Xenopus AQP3 was immunolocalized in the basolateral membrane of the principal cells of the ventral skin, the urinary bladder, the collecting duct and late distal tubule of the kidney, the absorptive epithelial cells of the large intestine, and the ciliated epithelial cells of the oviducts. Therefore, we designated this AQP as basolateral Xenopus AQP3 (AQP-x3BL). The intensity of labeling for AQP-x3BL differed between the ventral and dorsal skin, with the basolateral membrane of the principal cells in the ventral skin showing intense labeling, whereas that in the dorsal skin was lightly labeled. AQP-x3BL was also immunolocalized in the basolateral membrane of secretory cells in the small granular and mucous glands of the skin. As AQP-x5, a homolog of mammalian AQP5, is localized in the apical membrane of these same cells, this provides a pathway for fluid secretion by the glands. Although Hyla AQP-h2 is translocated from the cytoplasm to the apical membrane of the Hyla urinary bladder in response to arginine vasotocin (AVT), AQP-h2 immunoreactivity in Xenopus bladder remains in the cytoplasm and barely moves to the apical membrane, regardless of AVT stimulation. AQP-x3 is localized in the basolateral membrane, even though the AVT-stimulated AQP-h2 does not translocate to the apical membrane. These findings provide new insights into AQP function in aquatic anurans.