Douglas D N, Giband M, Altosaar I, Storey K B
Department of Chemistry, Carleton University, Ottawa, Canada.
J Comp Physiol B. 1994;164(5):405-14. doi: 10.1007/BF00302557.
The effects of anoxic submergence (16 h at 15 degrees C) on cellular mRNA contents were assessed in five organs of anoxia tolerant turtles Trachemys scripta elegans. Poly(A)+ RNA was extracted from liver, red and white skeletal muscle, kidney and heart of control and anoxic turtles, as well as from heart and kidney of turtles allowed 24 h aerobic recovery (at 15 degrees C) after anoxia exposure. Poly(A)+ RNA content increased by 30% in white muscle from anoxic turtles relative to control animals but was unchanged by metabolic state in other organs. Extracted mRNA was translated in vitro in a wheat germ lysate system and the 35S-labelled polypeptides that were produced were separated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Overall translational activity of the mRNA pool [cpm 35S-methionine incorporated per microgram poly(A)+ RNA] was altered by anoxia exposure in three organs, increasing by 38 and 18% in liver and kidney and decreasing by 42% in red muscle. Anoxia exposure also led to qualitative changes in the protein products that resulted from in vitro translation. Sodium dodecyl sulphate polyacrylamide gel electrophoresis revealed the presence of a novel 19.5-kDa polypeptide in liver of anoxia-exposed animals as well as increased amounts of two other proteins at 28.6 and 79.9 kDa. In heart a new translation product of 26.8 kDa appeared in anoxia, and in kidney a 32.8-kDa polypeptide was produced during the aerobic recovery period after anoxia exposure. Anoxia stimulated the appearance of a 37.5-kDa protein in red skeletal muscle but anoxic red muscle also lost proteins of 40, 32, and 28.2 kDa that were present in aerobic controls. Anoxia exposure did not change the proteins produced by in vitro translation in white muscle. The results suggest that anoxia exposure triggers rapid cellular responses in T. s. elegans that modify translatable mRNA populations in organs, leading to new protein transcripts.(ABSTRACT TRUNCATED AT 400 WORDS)
在耐缺氧的秀丽锦龟的五个器官中评估了缺氧淹没（15摄氏度下16小时）对细胞mRNA含量的影响。从对照龟和缺氧龟的肝脏、红白骨骼肌、肾脏和心脏中提取多聚腺苷酸加尾RNA（Poly(A)+ RNA），以及从缺氧暴露后经24小时有氧恢复（15摄氏度）的龟的心脏和肾脏中提取。相对于对照动物，缺氧龟白肌中的Poly(A)+ RNA含量增加了30%，但其他器官中的代谢状态未使其发生变化。提取的mRNA在小麦胚芽裂解物系统中进行体外翻译，产生的35S标记多肽通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳进行分离。缺氧暴露改变了三个器官中mRNA库的总体翻译活性[每微克Poly(A)+ RNA掺入的35S-甲硫氨酸的cpm值]，肝脏和肾脏中分别增加了38%和18%，红肌中减少了42%。缺氧暴露还导致体外翻译产生的蛋白质产物发生定性变化。十二烷基硫酸钠聚丙烯酰胺凝胶电泳显示，缺氧暴露动物的肝脏中存在一种新的19.5 kDa多肽，以及另外两种分子量分别为28.6 kDa和79.9 kDa的蛋白质含量增加。在心脏中，缺氧时出现了一种新的26.8 kDa翻译产物，在肾脏中，缺氧暴露后的有氧恢复期产生了一种32.8 kDa多肽。缺氧刺激了红骨骼肌中一种37.5 kDa蛋白质的出现，但缺氧红肌也失去了有氧对照中存在的40 kDa、32 kDa和28.2 kDa的蛋白质。缺氧暴露并未改变白肌中体外翻译产生的蛋白质。结果表明，缺氧暴露触发了秀丽锦龟细胞的快速反应，这些反应改变了器官中可翻译的mRNA群体，从而产生新的蛋白质转录本。（摘要截短至400字）
