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Dpp dependent Hematopoietic stem cells give rise to Hh dependent blood progenitors in larval lymph gland of Drosophila

View Article: PubMed Central - PubMed

ABSTRACT

Drosophila hematopoiesis bears striking resemblance with that of vertebrates, both in the context of distinct phases and the signaling molecules. Even though, there has been no evidence of Hematopoietic stem cells (HSCs) in Drosophila, the larval lymph gland with its Hedgehog dependent progenitors served as an invertebrate model of progenitor biology. Employing lineage-tracing analyses, we have now identified Notch expressing HSCs in the first instar larval lymph gland. Our studies clearly establish the hierarchical relationship between Notch expressing HSCs and the previously described Domeless expressing progenitors. These HSCs require Decapentapelagic (Dpp) signal from the hematopoietic niche for their maintenance in an identical manner to vertebrate aorta-gonadal-mesonephros (AGM) HSCs. Thus, this study not only extends the conservation across these divergent taxa, but also provides a new model that can be exploited to gain better insight into the AGM related Hematopoietic stem cells (HSCs).

Doi:: http://dx.doi.org/10.7554/eLife.18295.001

No MeSH data available.


Related in: MedlinePlus

Absence of apoptosis in Notch expressing cells in first instar lymph gland of Drosophila.(A–D") Time kinetics of N-Gal4, UAS-Apoliner show no apoptosis in N expressing cells at 8 hr (A–A"; n = 10), 13 hr (B–B"; n = 10), 18 hr (C–C"; n = 10) and 22 hr (D–D"; n = 10) AEH. Scale bar = 5 μm. Genotypes are shown on top of corresponding panels. DAPI marks the nucleus. Hours after larval hatching are as indicated in each panel.DOI:http://dx.doi.org/10.7554/eLife.18295.011
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fig2s2: Absence of apoptosis in Notch expressing cells in first instar lymph gland of Drosophila.(A–D") Time kinetics of N-Gal4, UAS-Apoliner show no apoptosis in N expressing cells at 8 hr (A–A"; n = 10), 13 hr (B–B"; n = 10), 18 hr (C–C"; n = 10) and 22 hr (D–D"; n = 10) AEH. Scale bar = 5 μm. Genotypes are shown on top of corresponding panels. DAPI marks the nucleus. Hours after larval hatching are as indicated in each panel.DOI:http://dx.doi.org/10.7554/eLife.18295.011

Mentions: Since we observed a reduction in the number of Notch positive cells post 13 hr AEH followed by their absence beyond 22 hr AEH, we investigated if these cells undergo cell death eventually. For this purpose we activated a sensor of apoptosis, UAS-Apoliner5 (Bardet et al., 2008) by N-Gal4. This sensor fly line harbors two fused fluorescent proteins that on caspase activity get differentially localized. While in non-apoptotic cells, the two fluorescent proteins mRFP and NLS-EGFP reside at the membrane, during apoptosis in the presence of active caspases, the NLS-EGFP gets accumulated in the nucleus. Interestingly, we could not detect any nuclear localized EGFP signal in the Notch expressing cells during this time line indicating that none of these cells undergo cell death (Figure 2—figure supplement 2A–D").


Dpp dependent Hematopoietic stem cells give rise to Hh dependent blood progenitors in larval lymph gland of Drosophila
Absence of apoptosis in Notch expressing cells in first instar lymph gland of Drosophila.(A–D") Time kinetics of N-Gal4, UAS-Apoliner show no apoptosis in N expressing cells at 8 hr (A–A"; n = 10), 13 hr (B–B"; n = 10), 18 hr (C–C"; n = 10) and 22 hr (D–D"; n = 10) AEH. Scale bar = 5 μm. Genotypes are shown on top of corresponding panels. DAPI marks the nucleus. Hours after larval hatching are as indicated in each panel.DOI:http://dx.doi.org/10.7554/eLife.18295.011
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Related In: Results  -  Collection

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fig2s2: Absence of apoptosis in Notch expressing cells in first instar lymph gland of Drosophila.(A–D") Time kinetics of N-Gal4, UAS-Apoliner show no apoptosis in N expressing cells at 8 hr (A–A"; n = 10), 13 hr (B–B"; n = 10), 18 hr (C–C"; n = 10) and 22 hr (D–D"; n = 10) AEH. Scale bar = 5 μm. Genotypes are shown on top of corresponding panels. DAPI marks the nucleus. Hours after larval hatching are as indicated in each panel.DOI:http://dx.doi.org/10.7554/eLife.18295.011
Mentions: Since we observed a reduction in the number of Notch positive cells post 13 hr AEH followed by their absence beyond 22 hr AEH, we investigated if these cells undergo cell death eventually. For this purpose we activated a sensor of apoptosis, UAS-Apoliner5 (Bardet et al., 2008) by N-Gal4. This sensor fly line harbors two fused fluorescent proteins that on caspase activity get differentially localized. While in non-apoptotic cells, the two fluorescent proteins mRFP and NLS-EGFP reside at the membrane, during apoptosis in the presence of active caspases, the NLS-EGFP gets accumulated in the nucleus. Interestingly, we could not detect any nuclear localized EGFP signal in the Notch expressing cells during this time line indicating that none of these cells undergo cell death (Figure 2—figure supplement 2A–D").

View Article: PubMed Central - PubMed

ABSTRACT

Drosophila hematopoiesis bears striking resemblance with that of vertebrates, both in the context of distinct phases and the signaling molecules. Even though, there has been no evidence of Hematopoietic stem cells (HSCs) in Drosophila, the larval lymph gland with its Hedgehog dependent progenitors served as an invertebrate model of progenitor biology. Employing lineage-tracing analyses, we have now identified Notch expressing HSCs in the first instar larval lymph gland. Our studies clearly establish the hierarchical relationship between Notch expressing HSCs and the previously described Domeless expressing progenitors. These HSCs require Decapentapelagic (Dpp) signal from the hematopoietic niche for their maintenance in an identical manner to vertebrate aorta-gonadal-mesonephros (AGM) HSCs. Thus, this study not only extends the conservation across these divergent taxa, but also provides a new model that can be exploited to gain better insight into the AGM related Hematopoietic stem cells (HSCs).

Doi:: http://dx.doi.org/10.7554/eLife.18295.001

No MeSH data available.


Related in: MedlinePlus