Yablonka-Reuveni Z, Paterson B M
Department of Biological Structure, School of Medicine, University of Washington, Seattle 98195, USA.
J Histochem Cytochem. 2001 Apr;49(4):455-62. doi: 10.1177/002215540104900405.
Isolated chicken myoblasts had previously been utilized in many studies aiming at understanding the emergence and regulation of the adult myogenic precursors (satellite cells). However, in recent years only a small number of chicken satellite cell studies have been published compared to the increasing number of studies with rodent satellite cells. In large part this is due to the lack of markers for tracing avian myogenic cells before they become terminally differentiated and express muscle-specific structural proteins. We previously demonstrated that myoblasts isolated from fetal and adult chicken muscle display distinct schedules of myosin heavy-chain isoform expression in culture. We further showed that myoblasts isolated from newly hatched and young chickens already possess the adult myoblast phenotype. In this article, we report on the use of polyclonal antibodies against the chicken myogenic regulatory factor proteins MyoD and myogenin for monitoring fetal and adult chicken myoblasts as they progress from proliferation to differentiation in culture. Fetal-type myoblasts were isolated from 11-day-old embryos and adult-type myoblasts were isolated from 3-week-old chickens. We conclude that fetal myoblasts express both MyoD and myogenin within the first day in culture and rapidly transit into the differentiated myosin-expressing state. In contrast, adult myoblasts are essentially negative for MyoD and myogenin by culture Day 1 and subsequently express first MyoD and then myogenin before expressing sarcomeric myosin. The delayed MyoD-to-myogenin transition in adult myoblasts is accompanied by a lag in the fusion into myotubes, compared to fetal myoblasts. We also report on the use of a commercial antibody against the myocyte enhancer factor 2A (MEF2A) to detect terminally differentiated chicken myoblasts by their MEF2+ nuclei. Collectively, the results support the hypothesis that fetal and adult myoblasts represent different phenotypic populations. The fetal myoblasts may already be destined for terminal differentiation at the time of their isolation, and the adult myoblasts may represent progenitors that reside in an earlier compartment of the myogenic lineage.
分离出的鸡成肌细胞此前已被用于许多旨在了解成年肌源性前体细胞（卫星细胞）的出现和调控的研究中。然而，近年来，与啮齿动物卫星细胞研究数量的不断增加相比，鸡卫星细胞的研究仅有少量发表。这在很大程度上是由于缺乏在禽类肌源性细胞终末分化并表达肌肉特异性结构蛋白之前追踪它们的标记物。我们之前证明，从胎儿和成年鸡肌肉中分离出的成肌细胞在培养中表现出不同的肌球蛋白重链同工型表达时间表。我们进一步表明，从刚孵化的雏鸡和幼鸡中分离出的成肌细胞已经具有成年成肌细胞的表型。在本文中，我们报告了使用针对鸡肌源性调节因子蛋白MyoD和生肌调节因子的多克隆抗体，来监测胎儿和成年鸡成肌细胞在培养中从增殖到分化的过程。胎儿型成肌细胞从11日龄胚胎中分离，成年型成肌细胞从3周龄鸡中分离。我们得出结论，胎儿成肌细胞在培养的第一天内同时表达MyoD和生肌调节因子，并迅速转变为表达肌球蛋白的分化状态。相比之下，成年成肌细胞在培养第1天时MyoD和生肌调节因子基本呈阴性，随后在表达肌节肌球蛋白之前先表达MyoD，然后表达生肌调节因子。与胎儿成肌细胞相比，成年成肌细胞中MyoD到生肌调节因子的转变延迟，同时在融合形成肌管方面也存在滞后。我们还报告了使用针对肌细胞增强因子2A（MEF2A）的商业抗体，通过其MEF2 + 细胞核来检测终末分化的鸡成肌细胞。总的来说，这些结果支持了胎儿和成肌细胞代表不同表型群体的假设。胎儿成肌细胞在分离时可能已经注定要进行终末分化，而成年成肌细胞可能代表位于肌源性谱系较早阶段的祖细胞。
