Segment-specific expression of tight junction proteins, claudin-2 and-10, in the rat epididymal epithelium
Segment-specific expression of tight junction proteins, claudin-2 and-10, in the rat epididymal epithelium
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DOI：
10.1679/aohc.68.213
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发表时间：
2005-09-01
影响因子：
--
通讯作者：
Shibata, Y
中科院分区：
文献类型：
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作者：
Guan, X;Inai, T;Shibata, Y
已知紧密连接与附睾腔液微环境的不同片段有关。我们检测了调节离子、溶质和水通过大鼠附睾紧密连接的细胞旁通透性的claudin的表达。RTPCR分析显示，在15个检测的claudin中，claudin-2和-10以片段特异性的方式表达。免疫荧光显微镜显示，这两种跛行动物在附睾上皮中都表现出发育阶段和节段特异性的亚细胞定位。在出生后第7天和第10周，Claudin-2主要在初始节段的顶端连接区检测到，而在包括头节、体节和尾节在内的所有远端节段均未表达。出生后第7天，Claudin-10主要在所有节段的顶端交界处检测到，但在第10周时，仅在起始节（特别是沿整个外侧膜）检测到。在冷冻断裂电镜下，在10周时，在P面上观察到发育良好的膜内颗粒链，在E面上观察到少量颗粒的互补凹槽。在初始段和远端头E面凹槽处偶见许多颗粒。在出生后第7天，紧密连接链连续且不被硝酸镧渗透，表明功能性紧密连接的建立。这些片段特异性的claudin-2和-10的表达可能有助于创造精子运输、成熟和储存所必需的特异性腔液微环境。
Tight junctions are known to be related to the variance by segment of the luminal fluid microenvironment of the epididymis. We examined the expression of claudins that regulate the paracellular permeability of ions, solutes, and water through tight junctions in the rat epididymis. RTPCR analysis showed that claudin-2 and -10 were expressed in a segment-specific manner among fifteen claudins examined. Immunofluorescence microscopy demonstrated that both claudins showed developmental stage- and segment-specific subcellular localizations in the epididymal epithelium. Claudin-2 was detected principally in the apical junctional region in the initial segment at postnatal day 7 and week 10 but lost its expression in all the distal segments including the caput, corpus, and cauda. Claudin-10 was detected principally in the apical junctional region in all segments on postnatal day 7 but only in the initial segment - especially along the entire lateral membrane - at 10 weeks. In freeze fracture electron microscopy, well-developed intramembranous particle strands were observed on the P face and complementary grooves with a few particles on the E face at 10 weeks. Many particles were occasionally observed on the grooves in the E face in the initial segment and distal caput. Tight junction strands were continuous and impermeable to lanthanum nitrate on postnatal day 7, suggesting the establishment of functional tight junctions. These segment-specific expressions of claudin-2 and -10 may contribute to creating the specific luminal fluid microenvironment which is necessary for the transport, maturation, and storage of spermatozoa.