Pvr expression regulators in equilibrium signal control and maintenance of Drosophila blood progenitors

Abstract

Blood progenitors within the lymph gland, a larval organ that supports hematopoiesis in Drosophila melanogaster, are maintained by integrating signals emanating from niche-like cells and those from differentiating blood cells. We term the signal from differentiating cells the ‘equilibrium signal’ in order to distinguish it from the ‘niche signal’. Earlier we showed that equilibrium signaling utilizes Pvr (the Drosophila PDGF/VEGF receptor), STAT92E, and adenosine deaminase-related growth factor A (ADGF-A) (Mondal et al., 2011). Little is known about how this signal initiates during hematopoietic development. To identify new genes involved in lymph gland blood progenitor maintenance, particularly those involved in equilibrium signaling, we performed a genetic screen that identified bip1 (bric à brac interacting protein 1) and Nucleoporin 98 (Nup98) as additional regulators of the equilibrium signal. We show that the products of these genes along with the Bip1-interacting protein RpS8 (Ribosomal protein S8) are required for the proper expression of Pvr.DOI: http://dx.doi.org/10.7554/eLife.03626.001

The EBF transcription factor Collier directly promotes Drosophila blood cell progenitor maintenance independently of the niche

“…Besides Col expression, other safeguard mechanisms exist to sustain prohemocyte fate. For instance, progenitor maintenance is intrinsically promoted by ROS signaling (33) as well as by signaling from the differentiated blood cells (34). The extracellular matrix of the MZ is also creating a particular microenvironment that controls prohemocyte behavior (35,36) and it is tempting to speculate that the dorsal heart vessel, which is lining the LG, may also participate in this process.…”

Growth Factor Signaling Regulates Mechanical Nociception in Flies and Vertebrates

“…Drosophila have a cognate receptor, Pvr, which is related to both PDGFR and VEGFR (Heino et al, 2001). Pvr and its three ligands (Pvf1, Pvf2, and Pvf3) mediate multiple physiological processes, including woundinduced cell migration (Wu et al, 2009), hemocyte proliferation (Munier et al, 2002), and cellular development and differentiation (Mondal et al, 2014). The role of Pvr in nociception in the fly has not been studied previously, and no previous work has determined whether VEGFRs modulate opioid tolerance.…”

The Drosophila histone demethylase dKDM5/LID regulates hematopoietic development

“…Some other histone lysine demethylases, like KDM4B and Jarid2, and the chromatin remodeling enzyme SMARCAD1 have also been identified as regulators of hemocytes development in Drosophila (Mondal et al, 2014;Stofanko et al, 2008). Furthermore, the unusual presence of lamellocytes without infestation, at expense of the prohemocytes pool, has already been reported in mutant contexts affecting chromatin remodeling or proliferation (Crozatier and Meister, 2007).…”

“…In this regard, we observed a strong upregulation of several transcription factors that stimulate the formation of prohemocytes (srp), plasmatocytes and crystal cells (lz and ush), providing a reasonable explanation for the contribution of dKDM5/LID to hemocytes proliferation and differentiation. In this respect, although not studied further, dKDM5/LID has been identified in a recent screening for genes involved in LG blood progenitor maintenance (Mondal et al, 2014). Interestingly, the mammalian KDM5 homologs have been related with cell proliferation disorders, such as cancer and X-linked mental retardation (Blair et al, 2011;Tahiliani et al, 2007), and a human translocation involving KDM5A and NUP98 was linked to leukemia (van Zutven et al, 2006).…”