Elucidating the Role of Uncharacterized Tin-Positive Pericardial Cells in Drosophila Heart Development
Drosophila is an excellent model system for studying developmental biology because of its small size, short generation time, the abundance of eggs laid, and the plethora of genetic tools for the manipulation of gene expression in time and space. In addition, many genes that cause human heart diseases are found in Drosophila and play similar roles in heart function and development. We are studying heart development at high spatio-temporal resolution in the fruit fly by single cell RNA sequencing of cardiac cells and whole mount in situ hybridization. Specifically, we are focusing on novel genes involved in heart development in fly embryos to learn what stages of development these genes are expressed and, using mutational analysis, to what extent they are required for the formation and differentiation of cardiac tissue.
We have found new marker genes for a group of uncharacterized embryonic pericardial cells that express the cardiac master regulator Tinman (tin-positive pericardial cells, TPCs), but not Even- or Odd-skipped, the other markers for pericardial cells. These TPCs co-express a specific set of genes, including cut, Wnt4, Nrt, Scb, CrzR, and DOR. We are conducting immunofluorescent staining and imaging of fly embryos to visualize the protein and mRNA expression patterns of these marker genes in the entire embryo, the heart, and heart-associated tissues. In addition, we are characterizing these cells to learn about their cell-specific roles during heart development. For the purpose of studying these roles in heart development, we are knocking down or overexpressing them in the embryonic heart using heart-specific Gal4 driver lines and examining trans-heterozygous combinations of loss of function alleles for these genes.
By determining the gene regulatory program of the TPCs and characterizing in-depth the development and function of these pericardial cells, we hope to elucidate their role in Drosophila heart development.