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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

Lineage tracing in an identical window reveals the hierarchical relationship between dome and Notch expressing cells.(A–B) Expression of Ci (Cubitus interruptus, red: B–B"), a marker of progenitors in transient N lineage traced (green) lymph gland following the scheme in A (n = 10). (C) is a cartoon showing overlap of dome and Ci (yellow), both validated markers of progenitors (D–D") Following restricted lineage tracing scheme in A, dome lineage tracing (green) marks much less number of progenitors (Ci; red; n = 5) in comparison of similarly lineage traced N. Compare D–D" to B–B". (E–E') Overlap of dome-MESO and tepIV, a downstream responder of same JAK/STAT pathway in a third instar lymph gland. (F–H) show three examples of restricted labeling of tepIV, following lineage tracing scheme in A (green; n = 8), marking much less number of cells in comparison of similarly lineage traced N (compare F–H with B). Scale bar 20 μm. Genotypes are shown on top of corresponding panels. TOPRO marks nucleus in E–E', while DAPI marks nucleus for rest.DOI:http://dx.doi.org/10.7554/eLife.18295.017
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fig5s1: Lineage tracing in an identical window reveals the hierarchical relationship between dome and Notch expressing cells.(A–B) Expression of Ci (Cubitus interruptus, red: B–B"), a marker of progenitors in transient N lineage traced (green) lymph gland following the scheme in A (n = 10). (C) is a cartoon showing overlap of dome and Ci (yellow), both validated markers of progenitors (D–D") Following restricted lineage tracing scheme in A, dome lineage tracing (green) marks much less number of progenitors (Ci; red; n = 5) in comparison of similarly lineage traced N. Compare D–D" to B–B". (E–E') Overlap of dome-MESO and tepIV, a downstream responder of same JAK/STAT pathway in a third instar lymph gland. (F–H) show three examples of restricted labeling of tepIV, following lineage tracing scheme in A (green; n = 8), marking much less number of cells in comparison of similarly lineage traced N (compare F–H with B). Scale bar 20 μm. Genotypes are shown on top of corresponding panels. TOPRO marks nucleus in E–E', while DAPI marks nucleus for rest.DOI:http://dx.doi.org/10.7554/eLife.18295.017

Mentions: We further endorsed the above finding by transient-lineage tracing of dome and tepIV expressing progenitors, following the same scheme that was employed for Notch (Figure 5—figure supplement 1A and Figure 5A). In case of N-Gal4, the transient activation of the lineage-tracing construct led to substantial labeling of the lymph gland (Figure 5—figure supplement 1B–B"and Figure 3C–C') including the dome positive and Cubitus interuptus+ (Ci+) hemocyte progenitors. Compared to this, activation of the lineage-tracing cassette with dome-Gal4 within the same short window resulted in generation of extremely restricted clonal expansion of dome expressing cells (Figure 5—figure supplement 1D–D"). This clearly showed that not enough multi-potent progenitors were born at that time to render labeling of the entire gland and that the potency of Notch expressing cells are higher than the dome positive ones. This was further validated by Ci expression (a specific marker for progenitors) that marked a large population of progenitors that were not lineage traced (Ci: red; Figure 5—figure supplement 1D–D"). Using tepIV-Gal4, another independent driver for hemocyte progenitors (Figure 5—figure supplement 1E–E'), a result akin to transient domeless activation was obtained (Figure 5—figure supplement 1F–H).


Dpp dependent Hematopoietic stem cells give rise to Hh dependent blood progenitors in larval lymph gland of Drosophila
Lineage tracing in an identical window reveals the hierarchical relationship between dome and Notch expressing cells.(A–B) Expression of Ci (Cubitus interruptus, red: B–B"), a marker of progenitors in transient N lineage traced (green) lymph gland following the scheme in A (n = 10). (C) is a cartoon showing overlap of dome and Ci (yellow), both validated markers of progenitors (D–D") Following restricted lineage tracing scheme in A, dome lineage tracing (green) marks much less number of progenitors (Ci; red; n = 5) in comparison of similarly lineage traced N. Compare D–D" to B–B". (E–E') Overlap of dome-MESO and tepIV, a downstream responder of same JAK/STAT pathway in a third instar lymph gland. (F–H) show three examples of restricted labeling of tepIV, following lineage tracing scheme in A (green; n = 8), marking much less number of cells in comparison of similarly lineage traced N (compare F–H with B). Scale bar 20 μm. Genotypes are shown on top of corresponding panels. TOPRO marks nucleus in E–E', while DAPI marks nucleus for rest.DOI:http://dx.doi.org/10.7554/eLife.18295.017
© Copyright Policy
Related In: Results  -  Collection

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fig5s1: Lineage tracing in an identical window reveals the hierarchical relationship between dome and Notch expressing cells.(A–B) Expression of Ci (Cubitus interruptus, red: B–B"), a marker of progenitors in transient N lineage traced (green) lymph gland following the scheme in A (n = 10). (C) is a cartoon showing overlap of dome and Ci (yellow), both validated markers of progenitors (D–D") Following restricted lineage tracing scheme in A, dome lineage tracing (green) marks much less number of progenitors (Ci; red; n = 5) in comparison of similarly lineage traced N. Compare D–D" to B–B". (E–E') Overlap of dome-MESO and tepIV, a downstream responder of same JAK/STAT pathway in a third instar lymph gland. (F–H) show three examples of restricted labeling of tepIV, following lineage tracing scheme in A (green; n = 8), marking much less number of cells in comparison of similarly lineage traced N (compare F–H with B). Scale bar 20 μm. Genotypes are shown on top of corresponding panels. TOPRO marks nucleus in E–E', while DAPI marks nucleus for rest.DOI:http://dx.doi.org/10.7554/eLife.18295.017
Mentions: We further endorsed the above finding by transient-lineage tracing of dome and tepIV expressing progenitors, following the same scheme that was employed for Notch (Figure 5—figure supplement 1A and Figure 5A). In case of N-Gal4, the transient activation of the lineage-tracing construct led to substantial labeling of the lymph gland (Figure 5—figure supplement 1B–B"and Figure 3C–C') including the dome positive and Cubitus interuptus+ (Ci+) hemocyte progenitors. Compared to this, activation of the lineage-tracing cassette with dome-Gal4 within the same short window resulted in generation of extremely restricted clonal expansion of dome expressing cells (Figure 5—figure supplement 1D–D"). This clearly showed that not enough multi-potent progenitors were born at that time to render labeling of the entire gland and that the potency of Notch expressing cells are higher than the dome positive ones. This was further validated by Ci expression (a specific marker for progenitors) that marked a large population of progenitors that were not lineage traced (Ci: red; Figure 5—figure supplement 1D–D"). Using tepIV-Gal4, another independent driver for hemocyte progenitors (Figure 5—figure supplement 1E–E'), a result akin to transient domeless activation was obtained (Figure 5—figure supplement 1F–H).

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