CELL ELONGATION IN THE CULTURED EMBRYONIC CHICK LENS EPITHELIUM WITH AND WITHOUT PROTEIN SYNTHESIS
CELL ELONGATION IN THE CULTURED EMBRYONIC CHICK LENS EPITHELIUM WITH AND WITHOUT PROTEIN SYNTHESIS
复制标题
有或没有蛋白质合成的培养胚胎鸡晶状体上皮细胞的伸长
作者：
J. Piatigorsky;H. Webster;M. Wollberg
先前的研究表明，6日龄胚鸡晶状体上皮细胞在组织培养中呈细长状。在本研究中，从组织学上考察了栽培第1天伸长的时间过程。培养的上皮细胞也分别用环己亚胺或秋水仙碱处理，以确定细胞伸长是否取决于新蛋白的合成和微管的利用。在培养的前5小时，平均细胞长度从11µ增加到21µ。随后，伸长率变慢；培养24小时后，细胞平均长度为28µ。连续暴露于环己亚胺不抑制细胞长度的最初加倍，但确实阻止进一步伸长。相比之下，秋水仙碱几乎立即抑制伸长。当细胞长度增加一倍后，加入环己亚胺和秋水仙碱均抑制细胞进一步伸长；处理后的细胞仍呈柱状。放射自显影和电泳试验表明，秋水仙碱对蛋白质合成没有明显影响，但环己亚胺抑制了蛋白质合成。电镜检查显示，单独血清和环己亚胺培养的上皮细胞中存在沿表面膜取向的微管，而秋水仙碱培养的上皮细胞中没有微管。这些结果表明，培养晶状体上皮细胞伸长的早期阶段需要预先存在的微管元件的初始组装和组织，并且持续的伸长还依赖于蛋白质的重新合成，可能是微管蛋白。
Previous studies have shown that cells in the 6-day old embryonic chick lens epithelium elongate in tissue culture. In the present study, the time course of elongation during the 1st day of cultivation has been examined histologically. Cultured epithelia were also treated with cycloheximide or colchicine in order to determine if cell elongation depends on new protein synthesis and on the utilization of microtubules, respectively. In the first 5 hr of culture, the mean cell length increased from 11 µ to 21 µ. Subsequently, elongation was slower; the mean cell length was 28 µ after 24 hr in culture. Continuous exposure to cycloheximide did not inhibit the initial doubling of cell length, but did prevent further elongation. By contrast, colchicine inhibited elongation almost immediately. When added after the cell length had doubled, cycloheximide and colchicine each inhibited further elongation; the treated cells remained columnar. Radioautographic and electrophoretic tests showed that protein synthesis was not appreciably affected by colchicine, but was suppressed by cycloheximide. Electron microscopic examination revealed that microtubules oriented along surface membranes were present in epithelia cultured with serum alone and with cycloheximide, but not in those incubated with colchicine. These results indicate that the early stages of cell elongation in the cultured lens epithelium require an initial assembly and organization of preexisting microtubular elements and that continued elongation depends, in addition, on the de novo synthesis of protein, possibly microtubule protein.