A FINE STRUCTURAL ANALYSIS OF INTERCELLULAR JUNCTIONS IN MOUSE LIVER
A FINE STRUCTURAL ANALYSIS OF INTERCELLULAR JUNCTIONS IN MOUSE LIVER
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DOI：
10.1083/jcb.45.2.272
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发表时间：
1970-01-01
影响因子：
7.8
通讯作者：
REVEL, JP
中科院分区：
文献类型：
--
作者：
GOODENOUGH, DA;REVEL, JP
在完整的小鼠肝脏和来自匀浆小鼠肝脏的富含连接的膜部分中检查了闭塞小带和间隙连接。这些制剂通过醋酸双氧铀整体染色、胶体镧染色、磷钨酸盐负染色和冷冻裂解技术进行可视化。闭合小带被布置为分支和吻合的线状接触的网状结构，将胆小管的内腔与肝脏细胞间隙密封。间隙连接的剖面特征是并列的连接膜外叶之间有 20 A 的间隙，并且用镧或磷钨酸盐渗透该空间，显示出中心间距为 90-100 A 的亚基的多边形晶格。冷冻裂解的间隙连接显示出类似的晶格。用 60% 丙酮水溶液提取富含连接处的级分会导致切片颗粒中 20 A 间隙消失，并且无法通过冷冻切割或负染色技术证明多边形晶格。用 50% 丙酮萃取膜不会产生这种效果。丙酮提取物的薄层色谱显示 60% 提取物中存在一组磷脂，而在 50% 提取物中未检测到这些磷脂。丙酮不会导致闭锁带结构发生任何可检测到的变化，但在丙酮处理后闭塞连接处会出现镧泄漏。报告了其他试剂对连接点的影响。
Zonulae occludentes and gap junctions were examined both in the intact mouse liver and in a junction-rich membrane fraction from homogenized mouse liver. These preparations were visualized with the techniques of uranyl acetate staining en bloc, staining with colloidal lanthanum, negative staining with phosphotungstate, and freeze-cleaving. The zonula occludens is arranged as a meshwork of branching and anastomosing threadlike contacts sealing the lumen of the bile canaliculus from the liver intercellular space. The gap junction is characterized in section by a 20 A gap between the apposed junctional membrane outer leaflets, and permeation of this space with lanthanum or phosphotungstate reveals a polygonal lattice of subunits with a center-to-center spacing of 90–100 A. Freeze-cleaved gap junctions show a similar lattice. Extraction of junction-rich fractions with 60% aqueous acetone results in a disappearance of the 20 A gap in sectioned pellets and an inability to demonstrate the polygonal lattice with either the freeze-cleave or negative staining techniques. Extraction of the membranes with 50% acetone does not produce this effect. Thin-layer chromatography of the acetone extracts reveals a group of phospholipids in the 60% extract that are not detectable in the 50% extract. Acetone does not cause any detectable change in the structure of the zonula occludens, but the occluding junction becomes leaky to lanthanum following acetone treatment. The effects of other reagents on the junctions are reported.