Knöll R, Arras M, Zimmermann R, Schaper J, Schaper W
Max-Planck-Institute, Department of Experimental Cardiology, Bad Nauheim, Germany.
Cardiovasc Res. 1994 Jul;28(7):1062-9. doi: 10.1093/cvr/28.7.1062.
Brief coronary occlusions cause upregulation of expression in a wide variety of genes. These changes in tissue mRNA concentration could have been produced by transcriptional or post-transcriptional events. The aim of this study was to discriminate between increased transcription and changes in mRNA stability using run-on assays with isolated myocyte nuclei.
Myocyte nuclei isolated from ischaemic/reperfused and normal myocardium were incubated with labelled ribonucleotides. The radioactive RNA was then hybridised with specific cDNA probes and slot blots were autoradiographed.
There was increased transcriptional activity for the proto-oncogenes c-myc, c-jun, jun-B, and jun-D. There were marked increases in transcriptional activity for sarcoplasmic Ca(2+)-ATPase, calmodulin, phospholamban, and calsequestrin. Strong transcriptional activity was found for the ubiquitin and heat shock protein (hsp27, hsp70) genes, and for PAI-1 and GAPDH. The transcription for the beta myosin heavy chain gene was not altered.
Changes in the tissue concentration of mRNA species following brief coronary occlusion and reperfusion are most often the result of altered transcriptional activity. Increased c-fos mRNA concentrations observed in earlier studies cannot be explained by transcriptional activity of myocytes during reperfusion. Calmodulin is strongly transcribed but tissue concentration stays constant. The overall pattern of gene expression is indicative of damage at the molecular level, and calcium binding proteins (among perhaps many others) are in need of repair.
短暂性冠状动脉闭塞可导致多种基因的表达上调。组织mRNA浓度的这些变化可能是由转录或转录后事件引起的。本研究的目的是通过使用分离的心肌细胞核进行核转录分析，区分转录增加和mRNA稳定性变化。
将从缺血/再灌注心肌和正常心肌中分离出的心肌细胞核与标记的核糖核苷酸一起孵育。然后将放射性RNA与特异性cDNA探针杂交，并对狭缝印迹进行放射自显影。
原癌基因c-myc、c-jun、jun-B和jun-D的转录活性增加。肌浆网Ca(2+) -ATP酶、钙调蛋白、受磷蛋白和肌集钙蛋白的转录活性显著增加。泛素和热休克蛋白（hsp27、hsp70）基因以及PAI-1和GAPDH有很强的转录活性。β肌球蛋白重链基因的转录未改变。
短暂性冠状动脉闭塞和再灌注后组织中mRNA种类浓度的变化最常见的原因是转录活性改变。早期研究中观察到的c-fos mRNA浓度增加不能用再灌注期间心肌细胞的转录活性来解释。钙调蛋白转录强烈，但组织浓度保持恒定。基因表达的总体模式表明在分子水平上存在损伤，并且钙结合蛋白（可能还有许多其他蛋白）需要修复。
