Drosophila has been extensively used to model the human blood-immune system, as both
systems share many developmental and immune response mechanisms. However, while many
human blood cell types have been identified, only three were found in flies: plasmatocytes,
crystal cells and lamellocytes. To better understand the complexity of fly blood system,
we used single-cell RNA sequencing technology to generate comprehensive gene expression
profiles for Drosophila circulating blood cells. In addition to the known cell types,
we identified two new Drosophila blood cell types: thanacytes and primocytes. Thanacytes,
which express many stimulus response genes, are involved in distinct responses to
different types of bacteria. Primocytes, which express cell fate commitment and signaling
genes, appear to be involved in keeping stem cells in the circulating blood. Furthermore,
our data revealed four novel plasmatocyte subtypes (Ppn(+), CAH7(+), Lsp(+) and reservoir
plasmatocytes), each with unique molecular identities and distinct predicted functions.
We also identified cross-species markers from Drosophila hemocytes to human blood
cells. Our analysis unveiled a more complex Drosophila blood system and broadened
the scope of using Drosophila to model human blood system in development and disease.
Copyright (C) 2020, Institute of Genetics and Developmental Biology, Chinese Academy
of Sciences, and Genetics Society of China. Published by Elsevier Limited and Science
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