Single-cell sequencing of the Drosophila embryonic heart and muscle cells during differentiation and maturation

The developing Drosophila heart consists of cardioblasts that differentiate into different types of cardiomyocytes and pericardial cells. A large body of work has identified numerous genes and pathways involved in heart specification and differentiation, downstream of cardiac transcription factors, such as Tinman (NKX2-5) and Dorsocross1/2/3 (TBX5). The advent of single-cell RNA sequencing (scRNAseq) technology allowed us for the first time to describe the transcriptome of different cardiac cell types in the Drosophila model at high resolution. Here, we applied scRNAseq on sorted cells of late-stage Drosophila embryos expressing a cardiac GFP reporter. We find distinct expression profiles of cardioblasts as they mature to cardiomyocytes, as well as discretely clustering pericardial cells, including a set expressing Tinman that potentially assist in heart morphogenesis. In addition, we describe other cell types that were sequenced as by-catch due to low but distinct extracardiac expression of the GFP reporter. Our studies on wildtype cardioblasts will be the foundation for investigating developmental profiles in mutant backgrounds and for generating gene regulatory networks at single-cell resolution during cardiogenesis. ### Competing Interest Statement The authors have declared no competing interest.