Restricted expression of cardiac myosin genes reveals regulated aspects of heart tube assembly in zebrafish
Restricted expression of cardiac myosin genes reveals regulated aspects of heart tube assembly in zebrafish
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DOI：
10.1006/dbio.1999.9406
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发表时间：
1999-10-01
影响因子：
2.7
通讯作者：
Stainier, DYR
中科院分区：
文献类型：
--
作者：
Yelon, D;Horne, SA;Stainier, DYR
胚胎脊椎动物的心脏分为两个主要的腔室，前心室和后心房。尽管心室和心房组织之间的根本差异已得到充分证明，但尚不清楚心脏前后（A-P）模式何时以及如何发生。两个斑马鱼心肌肌球蛋白基因，心肌肌球蛋白轻链2（cmlc 2）和心室肌球蛋白重链（vmhc）的表达模式，使我们能够区分两个群体的心肌前体细胞在早期阶段，心管形成之前。这些心肌亚群可能代表心室和心房前体，在心前中胚层内以内侧-外侧模式组织。我们的检查cmlc 2和vmhc的表达在整个过程中的心管组装表明的重要作用的中间结构，心锥，在这种早期的内侧-外侧模式的转换成A-P模式的心管。为了深入了解心管组装和图案化的遗传调控，我们研究了几种斑马鱼突变体中cmlc 2和vmhc的表达。对引起贲门裂的突变的分析表明，正确的心脏A-P模式的实现并不依赖于心脏融合。另一方面，心脏融合不能确保心室和心房的正确A-P方向，如心脏和灵魂突变所证明的，这阻碍了心脏锥体形态发生。最后，pandora突变干扰了早期内侧-外侧心肌模式的建立。总而言之，这些数据提出了新的模式的机制，调节形成一个图案的心管，并提供了一个重要的框架，为未来分析斑马鱼突变体在这一过程中的缺陷。(C)北京：科学出版社.
The embryonic vertebrate heart is divided into two major chambers, an anterior ventricle and a posterior atrium. Although the fundamental differences between ventricular and atrial tissues are well documented, it is not known when and how cardiac anterior-posterior (A-P) patterning occurs. The expression patterns of two zebrafish cardiac myosin genes, cardiac myosin light chain 2 (cmlc2) and ventricular myosin heavy chain (vmhc), allow us to distinguish two populations of myocardial precursors at an early stage, well before the heart tube forms. These myocardial subpopulations, which may represent the ventricular and atrial precursors, are organized in a medial-lateral pattern within the precardiac mesoderm. Our examinations of cmlc2 and vmhc expression throughout the process of heart tube assembly indicate the important role of an intermediate structure, the cardiac cone, in the conversion of this early medial-lateral pattern into the A-P pattern of the heart tube. To gain insight into the genetic regulation of heart tube assembly and patterning, we examine cmlc2 and vmhc expression in several zebrafish mutants. Analyses of mutations that cause cardia bifida demonstrate that the achievement of a proper cardiac A-P pattern does not depend upon cardiac fusion. On the other hand, cardiac fusion does not ensure the proper A-P orientation of the ventricle and atrium, as demonstrated by the heart and soul mutation, which blocks cardiac cone morphogenesis. Finally, the pandora mutation interferes with the establishment of the early medial-lateral myocardial pattern. Altogether, these data suggest new models for the mechanisms that regulate the formation of a patterned heart tube and provide an important framework for future analyses of zebrafish mutants with defects in this process. (C) 1999 Academic Press.