Reuner K H, Wiederhold M, Dunker P, Just I, Bohle R M, Kröger M, Katz N
Institut für Klinische Chemie und Pathobiochemie, Universität Giessen, Germany.
Eur J Biochem. 1995 May 15;230(1):32-7. doi: 10.1111/j.1432-1033.1995.0032i.x.
Treatment of rat hepatocytes with the filamentous-actin-stabilizing toxin phalloidin decreased the amount of globular actin by 77% in the cytosol and by 80% in the nucleus within 12 h. Simultaneously, actin mRNA was specifically increased by 230%. The de-novo synthesis of actin mRNA, as measured by nuclear run-on transcription, was enhanced by 250%. Treatment of cells with actinomycin D blocked the increase of actin mRNA. The apparent half-life of actin mRNA was not significantly altered during treatment with phalloidin. In contrast, the globular-actin-stabilizing botulinum C2 toxin increased the amount of cytosolic globular actin by 50% within 12 h. Simultaneously, the actin mRNA level was decreased by 62%. However, de-novo synthesis of actin mRNA was not impaired. The apparent half-life of actin mRNA was decreased by approximately 60% during treatment with C2 toxin. The data strongly suggest an autoregulatory control of actin synthesis on the basis of the globular/filamentous actin ratio in rat hepatocytes at the transcriptional as well as at the posttranscriptional levels.
用丝状肌动蛋白稳定毒素鬼笔环肽处理大鼠肝细胞，12小时内胞质溶胶中球形肌动蛋白的量减少了77%，细胞核中减少了80%。同时，肌动蛋白mRNA特异性增加了230%。通过细胞核连续转录测量，肌动蛋白mRNA的从头合成增加了250%。用放线菌素D处理细胞可阻断肌动蛋白mRNA的增加。在用鬼笔环肽处理期间，肌动蛋白mRNA的表观半衰期没有显著改变。相反，球形肌动蛋白稳定肉毒杆菌C2毒素在12小时内使胞质溶胶中球形肌动蛋白的量增加了50%。同时，肌动蛋白mRNA水平降低了62%。然而，肌动蛋白mRNA的从头合成并未受损。在用C2毒素处理期间，肌动蛋白mRNA的表观半衰期降低了约60%。这些数据有力地表明，在大鼠肝细胞中，基于球形/丝状肌动蛋白比率，在转录水平和转录后水平上对肌动蛋白合成存在自动调节控制。
