SYNTHESIS, MIGRATION, AND RELEASE OF PRECURSOR COLLAGEN BY ODONTOBLASTS AS VISUALIZED BY AUTORADIOGRAPHY AFTER [H-3]PROLINE ADMINISTRATION
SYNTHESIS, MIGRATION, AND RELEASE OF PRECURSOR COLLAGEN BY ODONTOBLASTS AS VISUALIZED BY AUTORADIOGRAPHY AFTER [H-3]PROLINE ADMINISTRATION
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DOI：
10.1083/jcb.60.1.92
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发表时间：
1974-01-01
影响因子：
7.8
通讯作者：
LEBLOND, CP
中科院分区：
文献类型：
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作者：
WEINSTOCK, M;LEBLOND, CP
采用电镜、组织化学、放射自显影等方法观察30 - 40 g大鼠门牙成牙细胞对牙本质胶原前体的形成。注射后2分钟，血脯氨酸标记高时，放射性仅限于粗内质网，表明它是胶原多肽前体，前- α链的合成部位。10分钟时，当血脯氨酸的标记已经下降时，在含有缠结线的高尔基囊的球形部分观察到放射性，在20分钟时，在含有平行线聚集体的圆柱形部分出现放射性。平行线的长度为280-350 nm，碳水化合物用低ph磷钨酸染色，醛类用甲基苯丙胺银染色（细胞外胶原原纤维染色）。标记从球形到圆柱形高尔基部分的传递与纠缠成平行线的重组有关，这被解释为前胶原分子的包装。20 ~ 30 min，分别标记分泌颗粒和分泌颗粒。这些结果表明，高尔基小囊的圆柱形部分转化为分泌颗粒，随后转化为分泌颗粒。在这些颗粒中，被认为是前胶原分子的平行线被运送到成牙细胞过程中。注射后90min和4h，预牙本质中出现标记物，说明分泌颗粒中标记物已释放到预牙本质中。这是由分泌颗粒与成牙突质膜融合所证明的。有人提出，前α链产生的前胶原分子组装成平行聚集体在高尔基体。前胶原分子随后在分泌颗粒中被运输到成牙细胞过程，并通过胞吐作用释放。在牙本质中，前胶原分子会产生原胶原分子，然后再聚合成胶原原纤维。
The elaboration of dentin collagen precursors by the odontoblasts in the incisor teeth of 30–40-g rats was investigated by electron microscopy, histochemistry, and radioautography after intravenous injection of tritium-labeled proline.At 2 min after injection, when the labeling of blood proline was high, radioactivity was restricted to the rough endoplasmic reticulum, indicating that it is the site of synthesis of the polypeptide precursors of collagen, the pro-alpha chains.At 10 min, when the labeling of blood proline had already declined, radioactivity was observed in spherical portions of Golgi saccules containing entangled threads, and, at 20 min, radioactivity appeared in cylindrical portions containing aggregates of parallel threads. The parallel threads measured 280–350 nm in length and stained with the low pH-phosphotungstic acid technique for carbohydrate and with the silver methenamine technique for aldehydes (as did extracellular collagen fibrils). The passage of label from spherical to cylindrical Golgi portions is associated with the reorganization of entangled into parallel threads, which is interpreted as the packing of procollagen molecules.Between 20 and 30 min, prosecretory and secretory granules respectively became labeled. These results indicate that the cylindrical portions of Golgi saccules transform into prosecretory and subsequently into secretory granules. Within these granules, the parallel threads, believed to be procollagen molecules, are transported to the odontoblast process.At 90 min and 4 h after injection, label was present in predentin, indicating that the labeled content of secretory granules had been released into predentin. This occurred by exocytosis as evidenced by the presence of secretory granules in fusion with the plasmalemma of the odontoblast process.It is proposed that pro-alpha chains give rise to procollagen molecules which assemble into parallel aggregates in the Golgi apparatus. Procollagen molecules are then transported within secretory granules to the odontoblast process and released by exocytosis. In predentin procollagen molecules would give rise to tropocollagen molecules, which would then polymerize into collagen fibrils.