EXPRESSION OF SARCOMERIC MYOSIN IN THE PRESUMPTIVE MYOCARDIUM OF CHICKEN EMBRYOS OCCURS WITHIN 6 HOURS OF MYOCYTE COMMITMENT
EXPRESSION OF SARCOMERIC MYOSIN IN THE PRESUMPTIVE MYOCARDIUM OF CHICKEN EMBRYOS OCCURS WITHIN 6 HOURS OF MYOCYTE COMMITMENT
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DOI：
10.1002/aja.1001930306
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发表时间：
1992-03-01
影响因子：
2.5
通讯作者：
FISCHMAN, DA
中科院分区：
文献类型：
--
作者：
HAN, Y;DENNIS, JE;FISCHMAN, DA
在心脏跳动开始前，用免疫化学方法研究了鸡胚胎(6-10期)心肌细胞中肌球蛋白重链(MyHC)的分布。用单抗MF20对胚胎进行染色，MF20是一种识别所有鸡肉瘤MyHC的试剂(Bader等人，1982)，然后用免疫荧光和免疫过氧化物酶标记后的半薄塑料包埋切片对胚胎进行检测。我们观察到，在所检测的31个胚胎中，29%的胚胎在第7阶段(0-2对体节)就能检测到肌球蛋白，到第8阶段(4对体节)，80%以上的胚胎是MF20+。每个胚胎有5对体节(8+期)，强烈标记MF20。标记首先在7到7+期被检测到，在内脏中胚层的多形性细胞内作为扩散的荧光信号，位于前肠门(AIP)两侧的两个新月形区域。随着发育的进展，两个新月形的区域在AIP的顶端合并，随着两个心管在第9期开始融合，MyHC+区域延伸到头骨和内侧。到体节体期9-10，肌球蛋白阳性细胞完全包围心管。从第7期到第9期，肌球蛋白信号没有肌节分布，即在第9期晚期和第10期之前，假定的心肌细胞中没有明显的MyHC条纹或周期性重复。半薄切片显示，肌球蛋白首先分布在心包体腔附近的肌细胞顶端。这些发现对心肌细胞的测定、分化和形态发生的意义进行了讨论。
The distribution of sarcomeric myosin heavy chain (MyHC) has been examined immunoctochemically in the presumptive myocardial cells of chicken embryos (stages 6-10) prior to the onset of the heart beat. Embryos were stained with monoclonal antibody MF20, a reagent which recognizes all chicken sarcomeric MyHCs (Bader et al., 1982), and then examined both in whole mount by immunofluorescence and in semithin, plastic-embedded sections following immunoperoxidase labeling. We observed that myosin could be detected as early as stage 7 (0-2 pairs of somites) in 29% of the 31 embryos examined, and by stage 8 (4 pairs of somites) more than 80% of the embryos were MF20+. Every embryo with 5 pairs of somites (stage 8 +) labeled strongly with MF20. Labeling was first detected at stage 7 to 7 + as a diffuse fluorescent signal within pleomorphic cells of the splanchnic mesoderm located in two crescent-shaped regions bordering each side of the anterior intestinal portal (AIP). With progressive development, the two crescent-shaped regions merged at the apex of the AIP, and as the two heart tubes began fusion at stage 9, the MyHC+ regions extended cranially and medially. By somite stages 9-10, the myosin-positive cells completely encircled the heart tube. From stages 7 to 9 the myosin signal had no sarcomeric distribution; i.e., there were no MyHC striations nor periodic repeats evident in the presumptive myocytes until late stage 9 and stage 10. Semithin sections revealed that myosin was first distributed in apical regions of the myocytes, adjacent to the pericardial coelom. The implications of these findings for myocyte determination, differentiation and morphogenesis are discussed.