Rentschler Stacey, Morley Gregory E, Fishman Glenn I
Mount Sinai School of Medicine, Box 1102, One Gustave L. Levy Place, New York, NY 10029-6754, USA.
Novartis Found Symp. 2003;250:194-205; discussion 205-9, 276-9.
The cardiac conduction system (CCS) is a network of cells responsible for the rhythmic and coordinated excitation of the heart. Components of the murine conduction system, including the peripheral Purkinje fibres, are morphologically indistinguishable from surrounding cardiomyocytes and there exists a paucity of molecular markers to specifically identify these cells. Recently, we identified a line of transgenic mice in which the lacZ reporter gene is expressed within the embryonic CCS beginning at 8.25 days post-conception (dpc); its expression appears to delineate the full extent of the CCS, including the distal Purkinje fibre network, throughout all subsequent stages of development. Moreover, using the highly sensitive technique of optical mapping of electrical activity in embryonic murine hearts, we provided evidence for functional specialization of components of the CCS as early as 10.5 dpc. Here, we summarize these findings and describe our initial efforts utilizing the CCS-lacZ mice to identify novel factors that promote CCS specialization.
心脏传导系统（CCS）是一个由细胞组成的网络，负责心脏有节律且协调的兴奋。小鼠传导系统的组成部分，包括外周浦肯野纤维，在形态上与周围的心肌细胞无法区分，并且缺乏特异性识别这些细胞的分子标记。最近，我们鉴定出了一种转基因小鼠品系，其中lacZ报告基因在受精后8.25天（dpc）开始在胚胎CCS中表达；其表达似乎描绘了整个发育后续阶段CCS的完整范围，包括远端浦肯野纤维网络。此外，利用胚胎期小鼠心脏电活动光学映射这种高灵敏度技术，我们早在10.5 dpc就提供了CCS各组成部分功能特化的证据。在此，我们总结这些发现，并描述我们利用CCS - lacZ小鼠识别促进CCS特化的新因子的初步研究。
