title: Blood cell progenitor maintenance: Collier barks out of the niche.
abstract: Drosophila lymph gland, a larval haematopoietic organ, has emerged as a popular model to study regulatory mechanisms controlling blood cell progenitor fate. In this organ, the Posterior Signaling Center (PSC), a small group of cells expressing the EBF transcription factor Collier, has been proposed to act as a niche required for progenitor maintenance. Accordingly, several reports showed that PSC size/activity modulation impacts on blood cell differentiation. Yet our recent results challenge this model. Indeed, we found that PSC ablation does not affect haematopoietic progenitor maintenance. This unexpected result led us to reinvestigate the role of the PSC and collier in hematopoiesis. Consistent with previous findings, the PSC appears required for the production of a specialized blood cell type in response to parasitization. Moreover, our results indicate that the massive blood cell differentiation observed in collier mutant larvae is not due to the lack of PSC but to collier expression within the haematopoietic progenitors. We thus propose a paradigm shift whereby larval blood cell progenitor maintenance is largely independent of the PSC but requires the cell-autonomous function of collier.
authors.affiliation: a Université de Toulouse; UPS; CBD (Center de Biologie du Développement) France CNRS, CBD UMR5547 , F-31062 Toulouse , France.|b Present address: The Francis Crick Institute ; London WC2A 3LY , UK.
authors.forename: Billel
authors.initials: B
authors.lastname: Benmimoun
authors.affiliation: a Université de Toulouse; UPS; CBD (Center de Biologie du Développement) France CNRS, CBD UMR5547 , F-31062 Toulouse , France.
authors.forename: Marc
authors.initials: M
authors.lastname: Haenlin
authors.affiliation: a Université de Toulouse; UPS; CBD (Center de Biologie du Développement) France CNRS, CBD UMR5547 , F-31062 Toulouse , France.
authors.forename: Lucas
authors.initials: L
authors.lastname: Waltzer
mesh_terms: D000818:Animals; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D006410:Hematopoiesis; D007814:Larva / Q000166:cytology / Q000378:metabolism; D015398:Signal Transduction; D055153:Stem Cell Niche; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D014157:Transcription Factors; C104357:kn protein, Drosophila
keywords: Collier/EBF; Drosophila; hematopoiesis; lymph gland; stem cell niche