Time-lapse analysis reveals local asymmetrical changes in C-looping heart tube.

Heart development has long served as a model system of left-right asymmetrical morphogenesis, and many key laterality genes have been shown to be involved in the process of asymmetrical heart looping. We established a time-lapse imaging system to observe the process of C-looping during chick heart development, and our observations showed that the C-looping is a very complicated process that involves several local changes in shape: the process can be divided into dextral rotation of the rostral and caudal segments with ventral bending in the rostral part and horizontal anti-clockwise rotation with enlargement of the left part in the caudal segment. Further experimental manipulations revealed characteristics of these morphological changes and regional interactions for the events, and we propose that asymmetrical enlargement of the caudal part is one of the targets of the laterality genes in the C-looping process. (c) 2008 Wiley-Liss, Inc.