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De novo neurogenesis by targeted expression of atoh7 to Müller glia cells.

Lust K, Sinn R, Pérez Saturnino A, Centanin L, Wittbrodt J - Development (2016)

Bottom Line: The resulting neurogenic clusters differentiate in vivo into various retinal neurons.We use signaling reporters to demonstrate that the Atoh7-induced regeneration-like response of MG cells is mimicked by Notch, resembling the behavior of early progenitors during retinogenesis.Our results uncover a new role for Atoh7 as a universal neurogenic factor, and illustrate how signaling modules are re-employed in diverse contexts to trigger different biological responses.

View Article: PubMed Central - PubMed

Affiliation: Centre for Organismal Studies (COS) Heidelberg, Im Neuenheimer Feld 230, Heidelberg 69120, Germany The Hartmut Hoffmann-Berling International Graduate School of Molecular and Cellular Biology (HBIGS), Heidelberg University, Heidelberg, Germany.

No MeSH data available.


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Neural differentiation of MG cells upon targeted expression of atoh7. (A,A′) Induction scheme (A) and constructs used for lineage analysis (A′). The rx2::ERT2Cre transgenic line mediates excision or inversion events in the GaudíBBW2.1 cassette that result in three possible FP readouts (see Fig. 5A″), which will be expressed by all daughter cells irrespective of their fate. (B-E″) Lineage of MG cells upon targeted atoh7 expression (n=3 out of six fish, data obtained from three independent experiments). Recombined EGFP-positive nuclei (white/green) located on one GS-positive MG process (white/magenta) can be found in the INL, the inner plexiform layer and the ONL (B″, arrowheads). Clusters of EGFP-positive cells are found in the ONL (D″, arrowhead). Single EGFP-positive cells can be detected in the amacrine cell layer (C″, arrowhead) and the RGC layer (E″, arrowhead). Scale bars: 10 µm. (F) MG cells respond to injuries by upregulating various transcription factors, which leads to proliferation, differentiation and regeneration of the lost cell types. Upon targeted induction of atoh7 in MG cells, proliferation and differentiation are induced even in the absence of an injury.
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DEV135905F7: Neural differentiation of MG cells upon targeted expression of atoh7. (A,A′) Induction scheme (A) and constructs used for lineage analysis (A′). The rx2::ERT2Cre transgenic line mediates excision or inversion events in the GaudíBBW2.1 cassette that result in three possible FP readouts (see Fig. 5A″), which will be expressed by all daughter cells irrespective of their fate. (B-E″) Lineage of MG cells upon targeted atoh7 expression (n=3 out of six fish, data obtained from three independent experiments). Recombined EGFP-positive nuclei (white/green) located on one GS-positive MG process (white/magenta) can be found in the INL, the inner plexiform layer and the ONL (B″, arrowheads). Clusters of EGFP-positive cells are found in the ONL (D″, arrowhead). Single EGFP-positive cells can be detected in the amacrine cell layer (C″, arrowhead) and the RGC layer (E″, arrowhead). Scale bars: 10 µm. (F) MG cells respond to injuries by upregulating various transcription factors, which leads to proliferation, differentiation and regeneration of the lost cell types. Upon targeted induction of atoh7 in MG cells, proliferation and differentiation are induced even in the absence of an injury.

Mentions: The full differentiation potential of an induced MG cell can only be addressed by following its entire lineage. We achieved that by using the ubiquitous GaudíBBW2.1 transgenic line, which allows labeling of cells within a lineage irrespective of their fate (see scheme in Fig. 7A,A′). We triggered recombination in rx2::ERT2Cre GaudíBBW2.1 control fish to follow the lineage of individual MG cells during homeostasis. We allowed the lineage to progress for 2 weeks and analyzed clones expressing nuclear EGFP, because it is the only fluorophore that labels nuclei unambiguously. In control fish, we observed labeled cells in the central retina only within the rx2 expression domain, i.e. MG cells and photoreceptors (data not shown). By contrast, when clonal labeling was followed by targeted atoh7 expression we found nuclear-labeled cells representing a clonal lineage distributed in all three nuclear layers (Fig. 7B-E″). Clonal derivatives of MG cells were negative for GS staining and exhibited the typical morphology of photoreceptor progenitors, amacrine cells and RGCs (Fig. 7B-E″). Together, these data show that a transient atoh7 induction in MG cells within a differentiated retina is sufficient to trigger a regeneration-like response that includes re-entry into the cell cycle and de novo neurogenesis in vivo (Fig. 7F).Fig. 7.


De novo neurogenesis by targeted expression of atoh7 to Müller glia cells.

Lust K, Sinn R, Pérez Saturnino A, Centanin L, Wittbrodt J - Development (2016)

Neural differentiation of MG cells upon targeted expression of atoh7. (A,A′) Induction scheme (A) and constructs used for lineage analysis (A′). The rx2::ERT2Cre transgenic line mediates excision or inversion events in the GaudíBBW2.1 cassette that result in three possible FP readouts (see Fig. 5A″), which will be expressed by all daughter cells irrespective of their fate. (B-E″) Lineage of MG cells upon targeted atoh7 expression (n=3 out of six fish, data obtained from three independent experiments). Recombined EGFP-positive nuclei (white/green) located on one GS-positive MG process (white/magenta) can be found in the INL, the inner plexiform layer and the ONL (B″, arrowheads). Clusters of EGFP-positive cells are found in the ONL (D″, arrowhead). Single EGFP-positive cells can be detected in the amacrine cell layer (C″, arrowhead) and the RGC layer (E″, arrowhead). Scale bars: 10 µm. (F) MG cells respond to injuries by upregulating various transcription factors, which leads to proliferation, differentiation and regeneration of the lost cell types. Upon targeted induction of atoh7 in MG cells, proliferation and differentiation are induced even in the absence of an injury.
© Copyright Policy - open-access
Related In: Results  -  Collection

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DEV135905F7: Neural differentiation of MG cells upon targeted expression of atoh7. (A,A′) Induction scheme (A) and constructs used for lineage analysis (A′). The rx2::ERT2Cre transgenic line mediates excision or inversion events in the GaudíBBW2.1 cassette that result in three possible FP readouts (see Fig. 5A″), which will be expressed by all daughter cells irrespective of their fate. (B-E″) Lineage of MG cells upon targeted atoh7 expression (n=3 out of six fish, data obtained from three independent experiments). Recombined EGFP-positive nuclei (white/green) located on one GS-positive MG process (white/magenta) can be found in the INL, the inner plexiform layer and the ONL (B″, arrowheads). Clusters of EGFP-positive cells are found in the ONL (D″, arrowhead). Single EGFP-positive cells can be detected in the amacrine cell layer (C″, arrowhead) and the RGC layer (E″, arrowhead). Scale bars: 10 µm. (F) MG cells respond to injuries by upregulating various transcription factors, which leads to proliferation, differentiation and regeneration of the lost cell types. Upon targeted induction of atoh7 in MG cells, proliferation and differentiation are induced even in the absence of an injury.
Mentions: The full differentiation potential of an induced MG cell can only be addressed by following its entire lineage. We achieved that by using the ubiquitous GaudíBBW2.1 transgenic line, which allows labeling of cells within a lineage irrespective of their fate (see scheme in Fig. 7A,A′). We triggered recombination in rx2::ERT2Cre GaudíBBW2.1 control fish to follow the lineage of individual MG cells during homeostasis. We allowed the lineage to progress for 2 weeks and analyzed clones expressing nuclear EGFP, because it is the only fluorophore that labels nuclei unambiguously. In control fish, we observed labeled cells in the central retina only within the rx2 expression domain, i.e. MG cells and photoreceptors (data not shown). By contrast, when clonal labeling was followed by targeted atoh7 expression we found nuclear-labeled cells representing a clonal lineage distributed in all three nuclear layers (Fig. 7B-E″). Clonal derivatives of MG cells were negative for GS staining and exhibited the typical morphology of photoreceptor progenitors, amacrine cells and RGCs (Fig. 7B-E″). Together, these data show that a transient atoh7 induction in MG cells within a differentiated retina is sufficient to trigger a regeneration-like response that includes re-entry into the cell cycle and de novo neurogenesis in vivo (Fig. 7F).Fig. 7.

Bottom Line: The resulting neurogenic clusters differentiate in vivo into various retinal neurons.We use signaling reporters to demonstrate that the Atoh7-induced regeneration-like response of MG cells is mimicked by Notch, resembling the behavior of early progenitors during retinogenesis.Our results uncover a new role for Atoh7 as a universal neurogenic factor, and illustrate how signaling modules are re-employed in diverse contexts to trigger different biological responses.

View Article: PubMed Central - PubMed

Affiliation: Centre for Organismal Studies (COS) Heidelberg, Im Neuenheimer Feld 230, Heidelberg 69120, Germany The Hartmut Hoffmann-Berling International Graduate School of Molecular and Cellular Biology (HBIGS), Heidelberg University, Heidelberg, Germany.

No MeSH data available.


Related in: MedlinePlus