Ariel Gomez R, Sturgill B C, Chevalier R L, Boyd D G, Lessard J L, Owens G K, Peach M J
Department of Pediatrics, University of Virginia, School of Medicine, Charlottesville 22908.
Cell Tissue Res. 1987 Oct;250(1):7-12. doi: 10.1007/BF00214647.
Actin, a cytoskeletal and contractile protein, is expressed in six different isoforms that exhibit striking specificity. No studies have considered the muscle-specific actin expression in multiple organ systems in the intact fetus. Using a monoclonal antibody (B4) which reacts specifically with the isoactins of the smooth and skeletal muscle our immunohistochemical study examined whole fetal body sections to follow the development of actin expression throughout the last third of gestation in the Wistar-Kyoto rat. B4 staining was exclusively localized to muscle, confirming its high specificity and its usefulness for studying the ontogeny of muscle-specific isoactins. At 15 days of gestation, B4 staining was detected in the heart, the thoracic aorta and the skeletal muscle of the chest wall. The distribution and intensity of staining in the heart were initially higher than in the aorta or skeletal muscle and remained unchanged throughout the remainder of gestation, suggesting that the maturation of cardiac actin expression is well developed, although not fully completed before birth. Expression of muscle-specific actins in skeletal muscle was age-dependent and correlated with the maturational changes of muscle cell precursors. B4 staining in the fetal kidney was not apparent until day 20 of gestation and was localized to the inner cortical vessels. in association with the most mature nephrons, suggesting a centrifugal maturation of the intrarenal vasculature. The intensity of B4 staining in most tissues including bronchi, bowel, diaphragm, chest wall muscle and peripheral and pulmonary arteries increased by the end of gestation.
肌动蛋白是一种细胞骨架和收缩蛋白，以六种不同的同工型表达，这些同工型表现出显著的特异性。尚无研究考虑完整胎儿多个器官系统中肌肉特异性肌动蛋白的表达情况。我们使用一种与平滑肌和骨骼肌的同工型肌动蛋白特异性反应的单克隆抗体（B4），通过免疫组织化学研究对整个胎儿身体切片进行检查，以追踪Wistar - Kyoto大鼠妊娠最后三分之一阶段肌动蛋白表达的发育情况。B4染色仅定位于肌肉，证实了其高特异性以及在研究肌肉特异性同工型肌动蛋白个体发生方面的实用性。在妊娠15天时，在心脏、胸主动脉和胸壁骨骼肌中检测到B4染色。心脏中染色的分布和强度最初高于主动脉或骨骼肌，并且在妊娠剩余时间内保持不变，这表明心脏肌动蛋白表达的成熟虽然在出生前尚未完全完成，但已发育良好。骨骼肌中肌肉特异性肌动蛋白的表达与年龄相关，并与肌肉细胞前体的成熟变化相关。胎儿肾脏中的B4染色直到妊娠20天才明显，并且定位于肾内皮质血管，与最成熟的肾单位相关，提示肾内血管系统的离心式成熟。到妊娠末期，包括支气管、肠、膈肌、胸壁肌肉以及外周和肺动脉在内的大多数组织中B4染色的强度增加。
