The cardiac mutant Mexican axolotl is a unique animal model for evaluation of cardiac myofibrillogenesis.
The cardiac mutant Mexican axolotl is a unique animal model for evaluation of cardiac myofibrillogenesis.
复制标题
心脏突变体墨西哥蝾螈是评估心肌原纤维形成的独特动物模型。
DOI：
10.1006/excr.1999.4419
复制
发表时间：
1999
影响因子：
3.7
通讯作者：
Lemanski,LF
中科院分区：
文献类型：
--
作者：
Zajdel,RW;Dube,DK;Lemanski,LF
来自心脏突变型墨西哥蝾螈（Ambystoma mexicanum）的心脏不能形成有组织的肌原纤维，也不能跳动。虽然先前的生化和免疫组化实验显示心脏原肌球蛋白可能减少，但尚不清楚这是否导致突变心脏缺乏有组织的肌原纤维。我们使用阳离子脂质体将兔和鸡的原肌球蛋白引入到整个心脏器官培养的胚胎蝾螈的整个心脏中。当用兔或鸡原肌球蛋白处理时，突变心脏组织良好的肌节肌原纤维数量显著增加。用FITC标记的兔原肌球蛋白检测外源蛋白掺入突变心脏的动力学，并证实培养的活心脏细胞对外源蛋白的摄取。通过4小时的转染，正常和突变的心脏被发现将FITC标记的原肌球蛋白肌原纤维。我们还将抗原肌球蛋白抗体（CH 1）递送到正常心脏中，以破坏现有的心脏肌原纤维，这也导致心率降低。与正常对照组相比，在心脏内检测到CH1抗体，肌原纤维的解体是明显的。引入C蛋白单克隆抗体（ALD 66）不会导致组织化肌原纤维的破坏。结果清楚地表明，鸡或兔原肌球蛋白可以被突变体心脏掺入，并且足以克服导致突变体中缺乏肌原纤维形成的因素。这一发现也表明，缺乏有组织的肌原纤维主要是由原肌球蛋白水平不足或突变心脏中的内源性原肌球蛋白不适合肌原纤维形成引起的，我们能够通过引入原肌球蛋白抗体来复制。此外，在整个心脏器官培养中，将特定的外源蛋白或抗体掺入墨西哥美西螈的正常和突变心脏中，提供了一个独特的模型来评估心脏发育和分化所需的收缩蛋白的功能作用。
Hearts from cardiac mutant Mexican axolotl,Ambystoma mexicanum,do not form organized myofibrils and fail to beat. Though previous biochemical and immunohistochemical experiments showed a possible reduction of cardiac tropomyosin it was not clear that this caused the lack of organized myofibrils in mutant hearts. We used cationic liposomes to introduce both rabbit and chicken tropomyosin protein into whole hearts of embryonic axolotls in whole heart organ cultures. The mutant hearts had a striking increase in the number of well-organized sarcomeric myofibrils when treated with rabbit or chicken tropomyosin. FITC-labeled rabbit tropomyosin was used to examine the kinetics of incorporation of the exogenous protein into mutant hearts and confirmed the uptake of exogenous protein by the cells of live hearts in culture. By 4 h of transfection, both normal and mutant hearts were found to incorporate FITC-labeled tropomyosin into myofibrils. We also delivered an anti-tropomyosin antibody (CH 1) into normal hearts to disrupt the existing cardiac myofibrils which also resulted in reduced heartbeat rates. CH1 antibody was detected within the hearts and disorganization of the myofibrils was apparent when compared to normal controls. Introduction of a C-protein monoclonal antibody (ALD 66) did not result in a disruption of organized myofibrils. The results show clearly that chicken or rabbit tropomyosin could be incorporated by the mutant hearts and that it was sufficient to overcome the factors causing a lack of myofibril formation in the mutant. This finding also suggests that a lack of organized myofibrils is caused primarily by either inadequate levels of tropomyosin or endogenous tropomyosin in mutant hearts is unsuitable for myofibril formation, which we were able to duplicate with the introduction of tropomyosin antibody. Furthermore, incorporation of a specific exogenous protein or antibody into normal and mutant hearts of the Mexican axolotl in whole heart organ culture offers an unique model to evaluate functionalroles of contractile proteins necessary for cardiac development and differentiation.