Drysdale T A, Patterson K D, Saha M, Krieg P A
Institute for Cellular and Molecular Biology and Department of Zoology, University of Texas at Austin, Austin, Texas, 78712, USA.
Dev Biol. 1997 Aug 15;188(2):205-15. doi: 10.1006/dbio.1997.8623.
While a number of transcription factors that are likely to play a role in cardiac differentiation have recently been described, the signals that lead to the expression of these factors remains poorly understood. Here we report that exposure of Xenopus embryos to continuous low levels of all-trans retinoic acid (RA), starting at the time of neural fold closure, blocks expression of myocardial differentiation markers. The development of the remainder of the embryo is relatively normal, suggesting that retinoic acid can act rather specifically on myocardial precursors. Indeed, the pattern of endocardial gene expression appears to remain unaffected by RA treatment. Although RA blocks myocardial gene expression, a superficially normal heart tube forms. The heart tube, however, fails to loop during subsequent development and never forms beating tissue. The effect of RA treatment on expression of myocardial genes is developmental stage dependent, since no influence is observed after myocardial differentiation has commenced. These data indicate that a vital component of the myocardial determination pathway is sensitive to retinoid signaling.
虽然最近已经描述了一些可能在心脏分化中发挥作用的转录因子，但导致这些因子表达的信号仍知之甚少。在这里我们报告，从神经褶闭合时开始，将非洲爪蟾胚胎暴露于持续低水平的全反式视黄酸（RA）中，会阻断心肌分化标志物的表达。胚胎其余部分的发育相对正常，这表明视黄酸可以相当特异性地作用于心肌前体。事实上，心内膜基因表达模式似乎不受RA处理的影响。虽然RA阻断心肌基因表达，但仍形成表面上正常的心脏管。然而，心脏管在随后的发育过程中未能环化，并且从未形成跳动组织。RA处理对心肌基因表达的影响取决于发育阶段，因为在心肌分化开始后未观察到影响。这些数据表明，心肌决定途径的一个重要组成部分对视黄酸信号敏感。
