Retroviral Cell Lineage Analysis in the Developing Chick Heart

The use of genetically modified retroviruses as agents for gene transfer has provided developmental biology with some of its most elegant and compelling research stories of the last few years. The growing recognition of the utility of retrovirally derived constructs is perhaps unsurprising given that over millennia, evolution has honed the shuttling of genetic material into the native stock-in-trade of this unique class of animal pathogen. One application in which retroviral approaches have particularly shone is in analysis of cell lineage during embryogenesis (reviewed in refs. 1 –5 ). In this chapter, we describe a methodology that has been successfully utilized for tracing cell fate in the developing chick heart using replication-defective constructs derived from the avian spleen necrosis virus (SNV) (6 ). This work has provided a fresh perspective of ventricular muscle revealing it has a compound organization based around the proliferative activity of facets of clonally related myocytes (7 ). It has also enabled the resolution of a number of longstanding questions in cardiovascular developmental biology, including the origin of cells comprising coronary vascular tissues (8 ) and the cardiac conduction system (9 ).