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A cnidarian homologue of an insect gustatory receptor functions in developmental body patterning.

Saina M, Busengdal H, Sinigaglia C, Petrone L, Oliveri P, Rentzsch F, Benton R - Nat Commun (2015)

Bottom Line: Morpholino-mediated knockdown of NvecGrl1 causes developmental patterning defects of this region, leading to animals lacking the apical sensory organ.A deuterostome Grl from the sea urchin Strongylocentrotus purpuratus displays similar patterns of developmental expression.These results reveal an early evolutionary origin of the insect chemosensory receptor family and raise the possibility that their ancestral role was in embryonic development.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Biology and Medicine, Center for Integrative Genomics, University of Lausanne, Genopode Building, CH-1015 Lausanne, Switzerland.

ABSTRACT
Insect gustatory and odorant receptors (GRs and ORs) form a superfamily of novel transmembrane proteins, which are expressed in chemosensory neurons that detect environmental stimuli. Here we identify homologues of GRs (Gustatory receptor-like (Grl) genes) in genomes across Protostomia, Deuterostomia and non-Bilateria. Surprisingly, two Grls in the cnidarian Nematostella vectensis, NvecGrl1 and NvecGrl2, are expressed early in development, in the blastula and gastrula, but not at later stages when a putative chemosensory organ forms. NvecGrl1 transcripts are detected around the aboral pole, considered the equivalent to the head-forming region of Bilateria. Morpholino-mediated knockdown of NvecGrl1 causes developmental patterning defects of this region, leading to animals lacking the apical sensory organ. A deuterostome Grl from the sea urchin Strongylocentrotus purpuratus displays similar patterns of developmental expression. These results reveal an early evolutionary origin of the insect chemosensory receptor family and raise the possibility that their ancestral role was in embryonic development.

No MeSH data available.


Related in: MedlinePlus

N. vectensis Grl1 is required for arboral pole patterning(a) Morphological phenotypes of N. vectensis embryos injected with either control (control#1) or NvecGrl1 (NvecGrl1#1) morpholino oligonucleotides, in which DNA (magenta) and the actin cytoskeleton (green) are labelled with TO-PRO-3 and Alexa Fluor 488 Phalloidin, respectively. The arrow marks the group of nuclei at the aboral pole that have translocated to a more basal position (towards the right of the image) in control but not NvecGrl1 morphants; this results in these cells forming a small indentation of the apical ectoderm (arrowhead). Scale bar = 100 μm (applies to all images). Quantification of the phenotypes is shown below.(b) Bright-field images of living 4 day planulae derived from N. vectensis embryos injected with either control (control#1) or NvecGrl1 (NvecGrl1#2) morpholino oligonucleotides revealing the failure in apical tuft develops in NvecGrl1 morphants. Quantification of the phenotypes is shown below. Scale bars = 100 μm.(c) RNA in situ hybridisation using probes against marker genes in animals injected with either control (control#1) or NvecGrl1 (NvecGrl1#1) morpholino oligonucleotides. Scale bar = 100 μm (applies to all images). Quantification of the phenotypes is shown below.
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Figure 5: N. vectensis Grl1 is required for arboral pole patterning(a) Morphological phenotypes of N. vectensis embryos injected with either control (control#1) or NvecGrl1 (NvecGrl1#1) morpholino oligonucleotides, in which DNA (magenta) and the actin cytoskeleton (green) are labelled with TO-PRO-3 and Alexa Fluor 488 Phalloidin, respectively. The arrow marks the group of nuclei at the aboral pole that have translocated to a more basal position (towards the right of the image) in control but not NvecGrl1 morphants; this results in these cells forming a small indentation of the apical ectoderm (arrowhead). Scale bar = 100 μm (applies to all images). Quantification of the phenotypes is shown below.(b) Bright-field images of living 4 day planulae derived from N. vectensis embryos injected with either control (control#1) or NvecGrl1 (NvecGrl1#2) morpholino oligonucleotides revealing the failure in apical tuft develops in NvecGrl1 morphants. Quantification of the phenotypes is shown below. Scale bars = 100 μm.(c) RNA in situ hybridisation using probes against marker genes in animals injected with either control (control#1) or NvecGrl1 (NvecGrl1#1) morpholino oligonucleotides. Scale bar = 100 μm (applies to all images). Quantification of the phenotypes is shown below.

Mentions: To investigate the function of NvecGrl1, we injected zygotes with morpholino oligonucleotides designed to block translation of this receptor, and examined development of these animals in parallel with those injected with control morpholinos (see Methods). Early developmental processes, including gastrulation, appeared to proceed normally in both NvecGrl1 and control morphant animals (Fig. 5a). However, NvecGrl1 morphants displayed pronounced morphological defects in the apical organ domain in planula larvae (Fig. 5a-b). In control animals, the first sign of apical organ formation is the translocation of the nuclei in a small group of cells at the aboral pole to a more basal position (Fig. 5a). These cells subsequently form a small indentation of the aboral ectoderm (Fig. 5a); this indentation is the site from which the long cilia of the apical organ emerge37. In NvecGrl1 morphants the initial basal movement of nuclei is absent or strongly reduced and no clear indentation develops (Fig. 5a). Correspondingly, the apical tuft is absent or consists of only few long cilia in 4 day-old NvecGrl1 morphants (Fig. 5b). These animals subsequently fail to develop into primary polyps (0%, n = 159 NvecGrl1 morphants, compared to control morphants 63%, n = 122). These defects were reproduced with a second morpholino against NvecGrl1 (<9% primary polyps, n = 109).


A cnidarian homologue of an insect gustatory receptor functions in developmental body patterning.

Saina M, Busengdal H, Sinigaglia C, Petrone L, Oliveri P, Rentzsch F, Benton R - Nat Commun (2015)

N. vectensis Grl1 is required for arboral pole patterning(a) Morphological phenotypes of N. vectensis embryos injected with either control (control#1) or NvecGrl1 (NvecGrl1#1) morpholino oligonucleotides, in which DNA (magenta) and the actin cytoskeleton (green) are labelled with TO-PRO-3 and Alexa Fluor 488 Phalloidin, respectively. The arrow marks the group of nuclei at the aboral pole that have translocated to a more basal position (towards the right of the image) in control but not NvecGrl1 morphants; this results in these cells forming a small indentation of the apical ectoderm (arrowhead). Scale bar = 100 μm (applies to all images). Quantification of the phenotypes is shown below.(b) Bright-field images of living 4 day planulae derived from N. vectensis embryos injected with either control (control#1) or NvecGrl1 (NvecGrl1#2) morpholino oligonucleotides revealing the failure in apical tuft develops in NvecGrl1 morphants. Quantification of the phenotypes is shown below. Scale bars = 100 μm.(c) RNA in situ hybridisation using probes against marker genes in animals injected with either control (control#1) or NvecGrl1 (NvecGrl1#1) morpholino oligonucleotides. Scale bar = 100 μm (applies to all images). Quantification of the phenotypes is shown below.
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Related In: Results  -  Collection

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Figure 5: N. vectensis Grl1 is required for arboral pole patterning(a) Morphological phenotypes of N. vectensis embryos injected with either control (control#1) or NvecGrl1 (NvecGrl1#1) morpholino oligonucleotides, in which DNA (magenta) and the actin cytoskeleton (green) are labelled with TO-PRO-3 and Alexa Fluor 488 Phalloidin, respectively. The arrow marks the group of nuclei at the aboral pole that have translocated to a more basal position (towards the right of the image) in control but not NvecGrl1 morphants; this results in these cells forming a small indentation of the apical ectoderm (arrowhead). Scale bar = 100 μm (applies to all images). Quantification of the phenotypes is shown below.(b) Bright-field images of living 4 day planulae derived from N. vectensis embryos injected with either control (control#1) or NvecGrl1 (NvecGrl1#2) morpholino oligonucleotides revealing the failure in apical tuft develops in NvecGrl1 morphants. Quantification of the phenotypes is shown below. Scale bars = 100 μm.(c) RNA in situ hybridisation using probes against marker genes in animals injected with either control (control#1) or NvecGrl1 (NvecGrl1#1) morpholino oligonucleotides. Scale bar = 100 μm (applies to all images). Quantification of the phenotypes is shown below.
Mentions: To investigate the function of NvecGrl1, we injected zygotes with morpholino oligonucleotides designed to block translation of this receptor, and examined development of these animals in parallel with those injected with control morpholinos (see Methods). Early developmental processes, including gastrulation, appeared to proceed normally in both NvecGrl1 and control morphant animals (Fig. 5a). However, NvecGrl1 morphants displayed pronounced morphological defects in the apical organ domain in planula larvae (Fig. 5a-b). In control animals, the first sign of apical organ formation is the translocation of the nuclei in a small group of cells at the aboral pole to a more basal position (Fig. 5a). These cells subsequently form a small indentation of the aboral ectoderm (Fig. 5a); this indentation is the site from which the long cilia of the apical organ emerge37. In NvecGrl1 morphants the initial basal movement of nuclei is absent or strongly reduced and no clear indentation develops (Fig. 5a). Correspondingly, the apical tuft is absent or consists of only few long cilia in 4 day-old NvecGrl1 morphants (Fig. 5b). These animals subsequently fail to develop into primary polyps (0%, n = 159 NvecGrl1 morphants, compared to control morphants 63%, n = 122). These defects were reproduced with a second morpholino against NvecGrl1 (<9% primary polyps, n = 109).

Bottom Line: Morpholino-mediated knockdown of NvecGrl1 causes developmental patterning defects of this region, leading to animals lacking the apical sensory organ.A deuterostome Grl from the sea urchin Strongylocentrotus purpuratus displays similar patterns of developmental expression.These results reveal an early evolutionary origin of the insect chemosensory receptor family and raise the possibility that their ancestral role was in embryonic development.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Biology and Medicine, Center for Integrative Genomics, University of Lausanne, Genopode Building, CH-1015 Lausanne, Switzerland.

ABSTRACT
Insect gustatory and odorant receptors (GRs and ORs) form a superfamily of novel transmembrane proteins, which are expressed in chemosensory neurons that detect environmental stimuli. Here we identify homologues of GRs (Gustatory receptor-like (Grl) genes) in genomes across Protostomia, Deuterostomia and non-Bilateria. Surprisingly, two Grls in the cnidarian Nematostella vectensis, NvecGrl1 and NvecGrl2, are expressed early in development, in the blastula and gastrula, but not at later stages when a putative chemosensory organ forms. NvecGrl1 transcripts are detected around the aboral pole, considered the equivalent to the head-forming region of Bilateria. Morpholino-mediated knockdown of NvecGrl1 causes developmental patterning defects of this region, leading to animals lacking the apical sensory organ. A deuterostome Grl from the sea urchin Strongylocentrotus purpuratus displays similar patterns of developmental expression. These results reveal an early evolutionary origin of the insect chemosensory receptor family and raise the possibility that their ancestral role was in embryonic development.

No MeSH data available.


Related in: MedlinePlus