sentence: It is therefore crucial to have a good characterization of the gene expression pattern and the selected transgenic reporter line when studying the development of the epicardium and its response to cardiac injury.Four zebrafish reporter lines marking the epicardium during development or regeneration have been reported : Et ( par3 : GFP ) [ 37 ] ; Tg ( tbx18 : DsRed ) , which , in addition to epicardial cells , is also reactivated in a few cardiomyocytes after injury in the adult and is thus not considered an appropriate line according to the authors [ 14 ] ; Tg ( tcf21 : DsRed ) [ 14 ] ; and Tg ( wt1b : GFP ) [ 16,17 ] .