Guo Wei, Pleitner Jonathan M, Saupe Kurt W, Greaser Marion L
Muscle Biology Laboratory, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.
Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.
PLoS One. 2013 Dec 19;8(12):e84281. doi: 10.1371/journal.pone.0084281. eCollection 2013.
Our recent study indicated that RNA binding motif 20 (Rbm20) alters splicing of titin and other genes. The current goals were to understand how the Rbm20(-/-) rat is related to physiological, structural, and molecular changes leading to heart failure. We quantitatively and qualitatively compared the expression of titin isoforms between Rbm20(-/-) and wild type rats by real time RT-PCR and SDS agarose electrophoresis. Isoform changes were linked to alterations in transcription as opposed to translation of titin messages. Reduced time to exhaustion with running in knockout rats also suggested a lower maximal cardiac output or decreased skeletal muscle performance. Electron microscopic observations of the left ventricle from knockout animals showed abnormal myofibril arrangement, Z line streaming, and lipofuscin deposits. Mutant skeletal muscle ultrastructure appeared normal. The results suggest that splicing alterations in Rbm20(-/-) rats resulted in pathogenic changes in physiology and cardiac ultrastructure. Secondary changes were observed in message levels for many genes whose splicing was not directly affected. Gene and protein expression data indicated the activation of pathophysiological and muscle stress-activated pathways. These data provide new insights on Rbm20 function and how its malfunction leads to cardiomyopathy.
我们最近的研究表明，RNA结合基序20（Rbm20）会改变肌联蛋白及其他基因的剪接。当前的目标是了解Rbm20基因敲除大鼠与导致心力衰竭的生理、结构和分子变化之间的关系。我们通过实时逆转录聚合酶链反应（RT-PCR）和十二烷基硫酸钠琼脂糖电泳，对Rbm20基因敲除大鼠和野生型大鼠之间肌联蛋白异构体的表达进行了定量和定性比较。异构体的变化与肌联蛋白信息的转录改变有关，而非翻译改变。基因敲除大鼠跑步至疲惫的时间缩短，这也表明其最大心输出量较低或骨骼肌性能下降。对基因敲除动物左心室的电子显微镜观察显示，肌原纤维排列异常、Z线移位和脂褐素沉积。突变型骨骼肌的超微结构看起来正常。结果表明，Rbm20基因敲除大鼠的剪接改变导致了生理和心脏超微结构的致病性变化。在许多剪接受间接影响的基因的信息水平上观察到了继发性变化。基因和蛋白质表达数据表明，病理生理和肌肉应激激活途径被激活。这些数据为Rbm20的功能以及其功能失调如何导致心肌病提供了新的见解。
