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The Drosophila homologue of Rootletin is required for mechanosensory function and ciliary rootlet formation in chordotonal sensory neurons.

Styczynska-Soczka K, Jarman AP - Cilia (2015)

Bottom Line: Knock-down of Rootletin results in loss of ciliary rootlet in these neurons and severe disruption of their sensory function.No evidence was found for a defect in cell division.Although our evidence is consistent with an anchoring role for the rootlet, severe loss of mechanosensory function of chordotonal (Ch) neurons upon Rootletin knock-down may suggest a direct role for the rootlet in the mechanotransduction mechanism itself.

View Article: PubMed Central - PubMed

Affiliation: Centre for Integrative Physiology, University of Edinburgh, Edinburgh, EH8 9XD UK.

ABSTRACT

Background: In vertebrates, rootletin is the major structural component of the ciliary rootlet and is also part of the tether linking the centrioles of the centrosome. Various functions have been ascribed to the rootlet, including maintenance of ciliary integrity through anchoring and facilitation of transport to the cilium or at the base of the cilium. In Drosophila, Rootletin function has not been explored.

Results: In the Drosophila embryo, Rootletin is expressed exclusively in cell lineages of type I sensory neurons, the only somatic cells bearing a cilium. Expression is strongest in mechanosensory chordotonal neurons. Knock-down of Rootletin results in loss of ciliary rootlet in these neurons and severe disruption of their sensory function. However, the sensory cilium appears largely normal in structure and in localisation of proteins suggesting no strong defect in ciliogenesis. No evidence was found for a defect in cell division.

Conclusions: The role of Rootletin as a component of the ciliary rootlet is conserved in Drosophila. In contrast, lack of a general role in cell division is consistent with lack of centriole tethering during the centrosome cycle in Drosophila. Although our evidence is consistent with an anchoring role for the rootlet, severe loss of mechanosensory function of chordotonal (Ch) neurons upon Rootletin knock-down may suggest a direct role for the rootlet in the mechanotransduction mechanism itself.

No MeSH data available.


Rootletin expression pattern and knock-down efficiency. a Schematic of protein structure of Drosophila and human Rootletins. Regions of high probability of coiled-coil (grey) were found by MARCOIL (http://toolkit.tuebingen.mpg.de/marcoil). The ‘rootletin’ domain is shown in red. b–gRootletin mRNA in embryos. b Wild type, stage 12. c Wild type, stage 14. d Wild type, stage 17, lch5 indicates lateral Ch organ clusters. e Higher magnification view of (d). eRootletin knock-down, stage 17. g Higher magnification view of (f). h Wild-type stage 17 embryo of a Rootletin-lacZ enhancer reporter fusion, showing β-galactosidase immunoreactivity in Ch neurons (green), counterstained for sensory neurons with anti-Futsch antibody (magenta). Lch5, v’ch1 and vchAB are the designations of the abdominal Ch neurons. i Schematic representation of the Drosophila Ch organ structure with sensory cilia at the tips of the neuronal dendrites housed in a scolopale structure
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Fig1: Rootletin expression pattern and knock-down efficiency. a Schematic of protein structure of Drosophila and human Rootletins. Regions of high probability of coiled-coil (grey) were found by MARCOIL (http://toolkit.tuebingen.mpg.de/marcoil). The ‘rootletin’ domain is shown in red. b–gRootletin mRNA in embryos. b Wild type, stage 12. c Wild type, stage 14. d Wild type, stage 17, lch5 indicates lateral Ch organ clusters. e Higher magnification view of (d). eRootletin knock-down, stage 17. g Higher magnification view of (f). h Wild-type stage 17 embryo of a Rootletin-lacZ enhancer reporter fusion, showing β-galactosidase immunoreactivity in Ch neurons (green), counterstained for sensory neurons with anti-Futsch antibody (magenta). Lch5, v’ch1 and vchAB are the designations of the abdominal Ch neurons. i Schematic representation of the Drosophila Ch organ structure with sensory cilia at the tips of the neuronal dendrites housed in a scolopale structure

Mentions: A second feature of Drosophila is that it has very few ciliated cell types. The only somatic cells bearing cilia are the type I sensory neurons, in which olfactory, gustatory or mechanosensory reception are performed via a specialised terminal cilium [15]. Whilst the cilia in these classes of neuron all have an associated rootlet, the most robust and prominent rootlets are found in the chordotonal (Ch) neurons [16, 17] (Fig. 1i). Ch neurons are auditory and proprioceptive mechanosensors and may be presumed to be under mechanical stress. Although nothing has been described of Rootletin function, it is highly represented in the transcriptome of Ch neurons [18]. We investigated the expression and function of Drosophila Rootletin with particular focus on Ch neuron structure and function.Fig. 1


The Drosophila homologue of Rootletin is required for mechanosensory function and ciliary rootlet formation in chordotonal sensory neurons.

Styczynska-Soczka K, Jarman AP - Cilia (2015)

Rootletin expression pattern and knock-down efficiency. a Schematic of protein structure of Drosophila and human Rootletins. Regions of high probability of coiled-coil (grey) were found by MARCOIL (http://toolkit.tuebingen.mpg.de/marcoil). The ‘rootletin’ domain is shown in red. b–gRootletin mRNA in embryos. b Wild type, stage 12. c Wild type, stage 14. d Wild type, stage 17, lch5 indicates lateral Ch organ clusters. e Higher magnification view of (d). eRootletin knock-down, stage 17. g Higher magnification view of (f). h Wild-type stage 17 embryo of a Rootletin-lacZ enhancer reporter fusion, showing β-galactosidase immunoreactivity in Ch neurons (green), counterstained for sensory neurons with anti-Futsch antibody (magenta). Lch5, v’ch1 and vchAB are the designations of the abdominal Ch neurons. i Schematic representation of the Drosophila Ch organ structure with sensory cilia at the tips of the neuronal dendrites housed in a scolopale structure
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4489026&req=5

Fig1: Rootletin expression pattern and knock-down efficiency. a Schematic of protein structure of Drosophila and human Rootletins. Regions of high probability of coiled-coil (grey) were found by MARCOIL (http://toolkit.tuebingen.mpg.de/marcoil). The ‘rootletin’ domain is shown in red. b–gRootletin mRNA in embryos. b Wild type, stage 12. c Wild type, stage 14. d Wild type, stage 17, lch5 indicates lateral Ch organ clusters. e Higher magnification view of (d). eRootletin knock-down, stage 17. g Higher magnification view of (f). h Wild-type stage 17 embryo of a Rootletin-lacZ enhancer reporter fusion, showing β-galactosidase immunoreactivity in Ch neurons (green), counterstained for sensory neurons with anti-Futsch antibody (magenta). Lch5, v’ch1 and vchAB are the designations of the abdominal Ch neurons. i Schematic representation of the Drosophila Ch organ structure with sensory cilia at the tips of the neuronal dendrites housed in a scolopale structure
Mentions: A second feature of Drosophila is that it has very few ciliated cell types. The only somatic cells bearing cilia are the type I sensory neurons, in which olfactory, gustatory or mechanosensory reception are performed via a specialised terminal cilium [15]. Whilst the cilia in these classes of neuron all have an associated rootlet, the most robust and prominent rootlets are found in the chordotonal (Ch) neurons [16, 17] (Fig. 1i). Ch neurons are auditory and proprioceptive mechanosensors and may be presumed to be under mechanical stress. Although nothing has been described of Rootletin function, it is highly represented in the transcriptome of Ch neurons [18]. We investigated the expression and function of Drosophila Rootletin with particular focus on Ch neuron structure and function.Fig. 1

Bottom Line: Knock-down of Rootletin results in loss of ciliary rootlet in these neurons and severe disruption of their sensory function.No evidence was found for a defect in cell division.Although our evidence is consistent with an anchoring role for the rootlet, severe loss of mechanosensory function of chordotonal (Ch) neurons upon Rootletin knock-down may suggest a direct role for the rootlet in the mechanotransduction mechanism itself.

View Article: PubMed Central - PubMed

Affiliation: Centre for Integrative Physiology, University of Edinburgh, Edinburgh, EH8 9XD UK.

ABSTRACT

Background: In vertebrates, rootletin is the major structural component of the ciliary rootlet and is also part of the tether linking the centrioles of the centrosome. Various functions have been ascribed to the rootlet, including maintenance of ciliary integrity through anchoring and facilitation of transport to the cilium or at the base of the cilium. In Drosophila, Rootletin function has not been explored.

Results: In the Drosophila embryo, Rootletin is expressed exclusively in cell lineages of type I sensory neurons, the only somatic cells bearing a cilium. Expression is strongest in mechanosensory chordotonal neurons. Knock-down of Rootletin results in loss of ciliary rootlet in these neurons and severe disruption of their sensory function. However, the sensory cilium appears largely normal in structure and in localisation of proteins suggesting no strong defect in ciliogenesis. No evidence was found for a defect in cell division.

Conclusions: The role of Rootletin as a component of the ciliary rootlet is conserved in Drosophila. In contrast, lack of a general role in cell division is consistent with lack of centriole tethering during the centrosome cycle in Drosophila. Although our evidence is consistent with an anchoring role for the rootlet, severe loss of mechanosensory function of chordotonal (Ch) neurons upon Rootletin knock-down may suggest a direct role for the rootlet in the mechanotransduction mechanism itself.

No MeSH data available.