pannier and pointedP2 act sequentially to regulate Drosophila heart development

Area of Science:

• Developmental biology
• Cell lineage tracing
• Genetics

Background:

• The Drosophila heart comprises cardioblasts forming the contractile tube and pericardial cells involved in hemolymph filtration.
• Understanding heart cell development is crucial for comprehending cardiovascular system formation.

Purpose of the Study:

• To complete the entire cell lineage of all heart cells in Drosophila.
• To identify key genetic regulators distinguishing posterior heart cell fates.

Main Methods:

• Comprehensive cell lineage mapping of Drosophila heart cells.
• Genetic screening to identify regulatory transcription factors.
• Analysis of specific gene isoforms (pointedP2) and signaling pathways (Ras/MAPK).

Main Results:

• A previously unrecognized distinction in heart cell lineages between anterior and posterior segments was identified.
• The ETS-transcription factor 'pointed' was found to regulate cardioblast and pericardial cell fates in posterior segments, promoting pericardial and inhibiting cardioblast development.
• The 'pointedP2' isoform was identified as the primary mediator of this function, potentially independent of Ras/MAPK signaling.
• The GATA transcription factor 'pannier' acts upstream of 'pointed', promoting cardiac mesoderm formation and subsequently influencing cell fate decisions.

Conclusions:

• Pannier initiates cardiac mesoderm development, while pointed acts downstream to specify distinct heart cell types in posterior segments.
• This study elucidates a novel developmental pathway controlling heart cell diversification in Drosophila.