Zanellato A M, Borrione A C, Giuriato L, Tonello M, Scannapieco G, Pauletto P, Sartore S
Institute of General Pathology, University of Padova, Italy.
Dev Biol. 1990 Oct;141(2):431-46. doi: 10.1016/0012-1606(90)90398-3.
Monoclonal anti-smooth muscle (SM-E7, SM-F11, and BF-48) and anti-nonmuscle (NM-A9 and NM-G2) myosin antibodies, Western blotting, and immunocytochemical procedures were used to study myosin isoform composition and distribution in the smooth muscle (SM) cells of bovine aorta differentiating in vivo and in vitro. Two myosin heavy chain (MHC) isoforms were identified by SM-E7 in adult aorta: SM-MHC-1 (Mr = 205 kDa) and SM-MHC-2 (Mr = 200 kDa), respectively. When tested with the SM-F11 antibody, SM-MHC-2 isoform showed distinct antigenic properties compared to SM-MHC-1. Two bands of 205 and 200 kDa were also present in the aortic SM tissue from 3-month-old fetus and were equally recognized by the BF-48 antibody. The 200-kDa SM myosin isoform was labeled by SM-F11 but not by SM-E7, thus indicating the existence of a fetal-specific SM-MHC-2 isoform. At the cellular level, both developing and adult bovine aortic tissues showed the existence of distinct patterns of myosin isoform expression. Three or even more aortic cell populations are differently distributed in areas which appear as (1) a network of interconnecting sheet-like or compact tissue (early fetus) and (2) enriched of collagenous-elastic or muscular tissue (adult animal). In addition, the SM-MHC-2 isoform of the fetal type appears to be uniquely distributed in cultured SM cells grown in vitro from adult bovine aortic explants. Our data indicate that in bovine aorta (1) MHC isoform expression is developmentally regulated and (2) the distribution of myosin isoforms is heterogenous both among and within aortic cells. These findings may be related to the distinct physiological properties displayed by SM during vascular myogenesis.
采用单克隆抗平滑肌（SM-E7、SM-F11和BF-48）和抗非肌肉（NM-A9和NM-G2）肌球蛋白抗体、蛋白质印迹法及免疫细胞化学方法，研究体内和体外分化的牛主动脉平滑肌（SM）细胞中肌球蛋白异构体的组成和分布。SM-E7在成年主动脉中鉴定出两种肌球蛋白重链（MHC）异构体：分别为SM-MHC-1（Mr = 205 kDa）和SM-MHC-2（Mr = 200 kDa）。用SM-F11抗体检测时，SM-MHC-2异构体与SM-MHC-1相比显示出不同的抗原特性。来自3个月大胎儿的主动脉SM组织中也存在205和200 kDa的两条条带，且均被BF-48抗体识别。200-kDa的SM肌球蛋白异构体被SM-F11标记，但未被SM-E7标记，因此表明存在胎儿特异性的SM-MHC-2异构体。在细胞水平上，发育中的和成年牛主动脉组织均显示出肌球蛋白异构体表达的不同模式。三个或更多的主动脉细胞群体在不同区域分布不同，这些区域表现为（1）相互连接的片状或致密组织网络（早期胎儿）和（2）富含胶原弹性或肌肉组织（成年动物）。此外，胎儿型的SM-MHC-2异构体似乎独特地分布在从成年牛主动脉外植体体外培养的SM细胞中。我们的数据表明，在牛主动脉中（1）MHC异构体表达受发育调控，（2）肌球蛋白异构体在主动脉细胞之间和内部的分布都是异质的。这些发现可能与血管肌生成过程中SM显示的不同生理特性有关。
