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Wnt affects symmetry and morphogenesis during post-embryonic development in colonial chordates.

Di Maio A, Setar L, Tiozzo S, De Tomaso AW - Evodevo (2015)

Bottom Line: Modulation of the Wnt signaling in either process has shown to result in unusual body axis phenotypes.Chemical manipulation of the pathway resulted in atypical budding due to the duplication of the A/P axes, supernumerary budding, and loss of the overall cell apical-basal polarity.Our results suggest that Wnt signaling is used for equivalent developmental processes both during embryogenesis and asexual development in an adult organism, suggesting that patterning mechanisms driving morphogenesis are conserved, independent of embryonic, or regenerative development.

View Article: PubMed Central - PubMed

Affiliation: School of Bioscience, University of Birmingham, Edgbaston, Birmingham, B19 2TT UK ; Molecular Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA 93106 USA.

ABSTRACT

Background: Wnt signaling is one of the earliest and most highly conserved regulatory pathways for the establishment of the body axes during regeneration and early development. In regeneration, body axes determination occurs independently of tissue rearrangement and early developmental cues. Modulation of the Wnt signaling in either process has shown to result in unusual body axis phenotypes. Botryllus schlosseri is a colonial ascidian that can regenerate its entire body through asexual budding. This processes leads to an adult body via a stereotypical developmental pathway (called blastogenesis), without proceeding through any embryonic developmental stages.

Results: In this study, we describe the role of the canonical Wnt pathway during the early stages of asexual development. We characterized expression of three Wnt ligands (Wnt2B, Wnt5A, and Wnt9A) by in situ hybridization and qRT-PCR. Chemical manipulation of the pathway resulted in atypical budding due to the duplication of the A/P axes, supernumerary budding, and loss of the overall cell apical-basal polarity.

Conclusions: Our results suggest that Wnt signaling is used for equivalent developmental processes both during embryogenesis and asexual development in an adult organism, suggesting that patterning mechanisms driving morphogenesis are conserved, independent of embryonic, or regenerative development.

No MeSH data available.


Related in: MedlinePlus

Spatio-temporal Wnt expression during early blostogenetic cycle. Expression patterns of wnt2B (magenta), wnt5A (green), and wnt9A (red) in Botryllus schlosseri buds processed for whole-mount FISH. All images are obtained by an average projection of the confocal z-stack image. The small sketch on the lower left corner of each panels represents the blastogenic stage of the buds shown (blue = secondary bud; light blue = primary bud), and the small arrow indicated their A/P orientation. (A) Confocal image of a primary (B) and secondary (b) buds at stage 9/8/2 showing expression of wnt2B on the emerging budlet (b) early in the blastogenesis. (B)wnt5A mRNA is expressed in immature germline cells within the gonadal blastema at stage 9/8/2. (C) At the same developmental stages considered, wnt9A is expressed predominantly within the secondary bud (b). Note that the epithelial wall of the vasculature (asterisk) also does express wnt9A.(D) Sense probe used on untreated buds as negative control for wnt2B. (E) Confocal image of wild type animal stained with a sense probe used as negative control for wnt5A. (F) Enlargement of the secondary bud (b) in panel C showing wnt9A expression. BARS: 200 μm in A, B, C, E. 100 μm in D and F.
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Fig2: Spatio-temporal Wnt expression during early blostogenetic cycle. Expression patterns of wnt2B (magenta), wnt5A (green), and wnt9A (red) in Botryllus schlosseri buds processed for whole-mount FISH. All images are obtained by an average projection of the confocal z-stack image. The small sketch on the lower left corner of each panels represents the blastogenic stage of the buds shown (blue = secondary bud; light blue = primary bud), and the small arrow indicated their A/P orientation. (A) Confocal image of a primary (B) and secondary (b) buds at stage 9/8/2 showing expression of wnt2B on the emerging budlet (b) early in the blastogenesis. (B)wnt5A mRNA is expressed in immature germline cells within the gonadal blastema at stage 9/8/2. (C) At the same developmental stages considered, wnt9A is expressed predominantly within the secondary bud (b). Note that the epithelial wall of the vasculature (asterisk) also does express wnt9A.(D) Sense probe used on untreated buds as negative control for wnt2B. (E) Confocal image of wild type animal stained with a sense probe used as negative control for wnt5A. (F) Enlargement of the secondary bud (b) in panel C showing wnt9A expression. BARS: 200 μm in A, B, C, E. 100 μm in D and F.

Mentions: To assess the putative role of Wnt proteins in early developmental processes, we characterized gene expression patterns of B. schlosseri wnt orthologs during the first 3 days of secondary bud development by FISH, prior to the onset of morphogenesis (from stage 9/7/1 to 9/8/3). As shown in Figure 2, wnt2B and wnt9A transcripts are expressed in the emerging secondary bud (Figure 2A, C, and F). In contrast, wnt5A seems to be expressed exclusively in a cell mass found in the mesenchymal space of the primary bud, which is part of the developing gonads (Figure 2B) (Langenbacher et al. [44]). We also found wnt9A expression in the epithelial wall of the vasculature (asterisk in Figure 2C) within all stages considered. The distribution of the wnt9A and wnt2B in the bud primordium appeared uniform in animals from 9/7/1 to 9/8/3 stage of blastogenesis whereas no signal was detected in the primary buds (Figure 2A and C). Furthermore, results from quantitative RT-PCR (Figure 3) analysis performed on cDNA pools from single systems confirmed the presence of wnt revealing the expression patterns of the ligands during early stages of the blastogenesis. Wnt2B and wnt9A showed similar trends of expression throughout these time periods, with no significant variability between stage 9/7/1 and 9/8/2 (Figure 3A and B). Wnt5A showed an opposite trend as in wnt2B with a slight increase in expression levels from stage 9/7/1 to 9/8/2 (Figure 3C). These data indicate that there is a trend in the wnt expression that follows the early development pattern of B. schlosseri.Figure 2


Wnt affects symmetry and morphogenesis during post-embryonic development in colonial chordates.

Di Maio A, Setar L, Tiozzo S, De Tomaso AW - Evodevo (2015)

Spatio-temporal Wnt expression during early blostogenetic cycle. Expression patterns of wnt2B (magenta), wnt5A (green), and wnt9A (red) in Botryllus schlosseri buds processed for whole-mount FISH. All images are obtained by an average projection of the confocal z-stack image. The small sketch on the lower left corner of each panels represents the blastogenic stage of the buds shown (blue = secondary bud; light blue = primary bud), and the small arrow indicated their A/P orientation. (A) Confocal image of a primary (B) and secondary (b) buds at stage 9/8/2 showing expression of wnt2B on the emerging budlet (b) early in the blastogenesis. (B)wnt5A mRNA is expressed in immature germline cells within the gonadal blastema at stage 9/8/2. (C) At the same developmental stages considered, wnt9A is expressed predominantly within the secondary bud (b). Note that the epithelial wall of the vasculature (asterisk) also does express wnt9A.(D) Sense probe used on untreated buds as negative control for wnt2B. (E) Confocal image of wild type animal stained with a sense probe used as negative control for wnt5A. (F) Enlargement of the secondary bud (b) in panel C showing wnt9A expression. BARS: 200 μm in A, B, C, E. 100 μm in D and F.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Fig2: Spatio-temporal Wnt expression during early blostogenetic cycle. Expression patterns of wnt2B (magenta), wnt5A (green), and wnt9A (red) in Botryllus schlosseri buds processed for whole-mount FISH. All images are obtained by an average projection of the confocal z-stack image. The small sketch on the lower left corner of each panels represents the blastogenic stage of the buds shown (blue = secondary bud; light blue = primary bud), and the small arrow indicated their A/P orientation. (A) Confocal image of a primary (B) and secondary (b) buds at stage 9/8/2 showing expression of wnt2B on the emerging budlet (b) early in the blastogenesis. (B)wnt5A mRNA is expressed in immature germline cells within the gonadal blastema at stage 9/8/2. (C) At the same developmental stages considered, wnt9A is expressed predominantly within the secondary bud (b). Note that the epithelial wall of the vasculature (asterisk) also does express wnt9A.(D) Sense probe used on untreated buds as negative control for wnt2B. (E) Confocal image of wild type animal stained with a sense probe used as negative control for wnt5A. (F) Enlargement of the secondary bud (b) in panel C showing wnt9A expression. BARS: 200 μm in A, B, C, E. 100 μm in D and F.
Mentions: To assess the putative role of Wnt proteins in early developmental processes, we characterized gene expression patterns of B. schlosseri wnt orthologs during the first 3 days of secondary bud development by FISH, prior to the onset of morphogenesis (from stage 9/7/1 to 9/8/3). As shown in Figure 2, wnt2B and wnt9A transcripts are expressed in the emerging secondary bud (Figure 2A, C, and F). In contrast, wnt5A seems to be expressed exclusively in a cell mass found in the mesenchymal space of the primary bud, which is part of the developing gonads (Figure 2B) (Langenbacher et al. [44]). We also found wnt9A expression in the epithelial wall of the vasculature (asterisk in Figure 2C) within all stages considered. The distribution of the wnt9A and wnt2B in the bud primordium appeared uniform in animals from 9/7/1 to 9/8/3 stage of blastogenesis whereas no signal was detected in the primary buds (Figure 2A and C). Furthermore, results from quantitative RT-PCR (Figure 3) analysis performed on cDNA pools from single systems confirmed the presence of wnt revealing the expression patterns of the ligands during early stages of the blastogenesis. Wnt2B and wnt9A showed similar trends of expression throughout these time periods, with no significant variability between stage 9/7/1 and 9/8/2 (Figure 3A and B). Wnt5A showed an opposite trend as in wnt2B with a slight increase in expression levels from stage 9/7/1 to 9/8/2 (Figure 3C). These data indicate that there is a trend in the wnt expression that follows the early development pattern of B. schlosseri.Figure 2

Bottom Line: Modulation of the Wnt signaling in either process has shown to result in unusual body axis phenotypes.Chemical manipulation of the pathway resulted in atypical budding due to the duplication of the A/P axes, supernumerary budding, and loss of the overall cell apical-basal polarity.Our results suggest that Wnt signaling is used for equivalent developmental processes both during embryogenesis and asexual development in an adult organism, suggesting that patterning mechanisms driving morphogenesis are conserved, independent of embryonic, or regenerative development.

View Article: PubMed Central - PubMed

Affiliation: School of Bioscience, University of Birmingham, Edgbaston, Birmingham, B19 2TT UK ; Molecular Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA 93106 USA.

ABSTRACT

Background: Wnt signaling is one of the earliest and most highly conserved regulatory pathways for the establishment of the body axes during regeneration and early development. In regeneration, body axes determination occurs independently of tissue rearrangement and early developmental cues. Modulation of the Wnt signaling in either process has shown to result in unusual body axis phenotypes. Botryllus schlosseri is a colonial ascidian that can regenerate its entire body through asexual budding. This processes leads to an adult body via a stereotypical developmental pathway (called blastogenesis), without proceeding through any embryonic developmental stages.

Results: In this study, we describe the role of the canonical Wnt pathway during the early stages of asexual development. We characterized expression of three Wnt ligands (Wnt2B, Wnt5A, and Wnt9A) by in situ hybridization and qRT-PCR. Chemical manipulation of the pathway resulted in atypical budding due to the duplication of the A/P axes, supernumerary budding, and loss of the overall cell apical-basal polarity.

Conclusions: Our results suggest that Wnt signaling is used for equivalent developmental processes both during embryogenesis and asexual development in an adult organism, suggesting that patterning mechanisms driving morphogenesis are conserved, independent of embryonic, or regenerative development.

No MeSH data available.


Related in: MedlinePlus