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Cep70 and Cep131 contribute to ciliogenesis in zebrafish embryos.

Wilkinson CJ, Carl M, Harris WA - BMC Cell Biol. (2009)

Bottom Line: Both Cep70 and Cep131 possess a putative HDAC (histone deacetylase) interacting domain.Cep70 and Cep131 contribute to ciliogenesis in many tissues in the zebrafish embryo: cilia are made in cep70 and cep131 morphant zebrafish embryos but are shortened.We propose that the role of these centrosomal/basal body proteins is in making the cilium and that they are involved in determination of the length of the axoneme.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, UK. Christopher.Wilkinson@rhul.ac.uk

ABSTRACT

Background: The centrosome is the cell's microtubule organising centre, an organelle with important roles in cell division, migration and polarity. However, cells can divide and flies can, for a large part of development, develop without them. Many centrosome proteins have been identified but the roles of most are still poorly understood. The centrioles of the centrosome are similar to the basal bodies of cilia, hair-like extensions of many cells that have important roles in cell signalling and development. In a number of human diseases, such Bardet-Biedl syndrome, centrosome/cilium proteins are mutated, leading to polycystic kidney disease, situs inversus, and neurological problems, amongst other symptoms.

Results: We describe zebrafish (Danio rerio) embryos depleted for two uncharacterised, centrosome proteins, Cep70 and Cep131. The phenotype of these embryos resembles that of zebrafish mutants for intraflagellar transport proteins (IFTs), with kidney and ear development affected and left-right asymmetry randomised. These organs and processes are those affected in Bardet-Biedl syndrome and other similar diseases. Like these diseases, the root cause of the phenotype lies, in fact, in dysfunctional cilia, which are shortened but not eliminated in several tissues in the morphants. Centrosomes and basal bodies, on the other hand, are present. Both Cep70 and Cep131 possess a putative HDAC (histone deacetylase) interacting domain. However, we could not detect in yeast two-hybrid assays any interaction with the deacetylase that controls cilium length, HDAC6, or any of the IFTs that we tested.

Conclusion: Cep70 and Cep131 contribute to ciliogenesis in many tissues in the zebrafish embryo: cilia are made in cep70 and cep131 morphant zebrafish embryos but are shortened. We propose that the role of these centrosomal/basal body proteins is in making the cilium and that they are involved in determination of the length of the axoneme.

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Convergence-extension is unaffected in cep70 morphants. (A-F) Defective epiboly in cep70 morphant (cep131 morphants normal at this stage). At 70% epiboly, morphant embryos (B) have an acorn shape, unlike normal development at this stage (A). As epiboly completes, morphant embryos (D) (WT shown in C) extrude some of the yolk but will recover and survive. Assaying convergence-extension by the distance between anterior neural margin and prechordal plate by wholemount in situ hybridisation for dlx3 (purple) and hgg1 (light blue) reveals no difference between morphant (F) and WT (E). Scale bar: 125 μm.
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Figure 6: Convergence-extension is unaffected in cep70 morphants. (A-F) Defective epiboly in cep70 morphant (cep131 morphants normal at this stage). At 70% epiboly, morphant embryos (B) have an acorn shape, unlike normal development at this stage (A). As epiboly completes, morphant embryos (D) (WT shown in C) extrude some of the yolk but will recover and survive. Assaying convergence-extension by the distance between anterior neural margin and prechordal plate by wholemount in situ hybridisation for dlx3 (purple) and hgg1 (light blue) reveals no difference between morphant (F) and WT (E). Scale bar: 125 μm.

Mentions: Defects in convergence and extension have been shown for some cilium morphants, such as the BBS proteins [41,42]. cep70 morphants have a phenotype similar to some mutants, such as silberblick and trilobite, whose role in convergence-extension are well established [43-45]. At the end of epiboly, cep70 morphant embryos adopt an acorn shape and part of the yolk is squeezed out as the germ ring contracts (Fig. 6A–D); their body axis is also shorter (Fig. 1). We assayed the effectiveness of convergence and extension in cep70 embryos by wholemount in situ hybridisation of tailbud stage embryos with RNA probes to dlx3 and hgg1 [46,47], which label the anterior neural margin and prechordal plate. In convergence-extension mutants, there is a significant gap between the two, which is absent in wild-type embryos (Fig. 6E) [44]. Such a gap is also absent in cep70 morphants (Fig. 6F) so, by this assay, early convergence-extension is proceeding normally.


Cep70 and Cep131 contribute to ciliogenesis in zebrafish embryos.

Wilkinson CJ, Carl M, Harris WA - BMC Cell Biol. (2009)

Convergence-extension is unaffected in cep70 morphants. (A-F) Defective epiboly in cep70 morphant (cep131 morphants normal at this stage). At 70% epiboly, morphant embryos (B) have an acorn shape, unlike normal development at this stage (A). As epiboly completes, morphant embryos (D) (WT shown in C) extrude some of the yolk but will recover and survive. Assaying convergence-extension by the distance between anterior neural margin and prechordal plate by wholemount in situ hybridisation for dlx3 (purple) and hgg1 (light blue) reveals no difference between morphant (F) and WT (E). Scale bar: 125 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2662791&req=5

Figure 6: Convergence-extension is unaffected in cep70 morphants. (A-F) Defective epiboly in cep70 morphant (cep131 morphants normal at this stage). At 70% epiboly, morphant embryos (B) have an acorn shape, unlike normal development at this stage (A). As epiboly completes, morphant embryos (D) (WT shown in C) extrude some of the yolk but will recover and survive. Assaying convergence-extension by the distance between anterior neural margin and prechordal plate by wholemount in situ hybridisation for dlx3 (purple) and hgg1 (light blue) reveals no difference between morphant (F) and WT (E). Scale bar: 125 μm.
Mentions: Defects in convergence and extension have been shown for some cilium morphants, such as the BBS proteins [41,42]. cep70 morphants have a phenotype similar to some mutants, such as silberblick and trilobite, whose role in convergence-extension are well established [43-45]. At the end of epiboly, cep70 morphant embryos adopt an acorn shape and part of the yolk is squeezed out as the germ ring contracts (Fig. 6A–D); their body axis is also shorter (Fig. 1). We assayed the effectiveness of convergence and extension in cep70 embryos by wholemount in situ hybridisation of tailbud stage embryos with RNA probes to dlx3 and hgg1 [46,47], which label the anterior neural margin and prechordal plate. In convergence-extension mutants, there is a significant gap between the two, which is absent in wild-type embryos (Fig. 6E) [44]. Such a gap is also absent in cep70 morphants (Fig. 6F) so, by this assay, early convergence-extension is proceeding normally.

Bottom Line: Both Cep70 and Cep131 possess a putative HDAC (histone deacetylase) interacting domain.Cep70 and Cep131 contribute to ciliogenesis in many tissues in the zebrafish embryo: cilia are made in cep70 and cep131 morphant zebrafish embryos but are shortened.We propose that the role of these centrosomal/basal body proteins is in making the cilium and that they are involved in determination of the length of the axoneme.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, UK. Christopher.Wilkinson@rhul.ac.uk

ABSTRACT

Background: The centrosome is the cell's microtubule organising centre, an organelle with important roles in cell division, migration and polarity. However, cells can divide and flies can, for a large part of development, develop without them. Many centrosome proteins have been identified but the roles of most are still poorly understood. The centrioles of the centrosome are similar to the basal bodies of cilia, hair-like extensions of many cells that have important roles in cell signalling and development. In a number of human diseases, such Bardet-Biedl syndrome, centrosome/cilium proteins are mutated, leading to polycystic kidney disease, situs inversus, and neurological problems, amongst other symptoms.

Results: We describe zebrafish (Danio rerio) embryos depleted for two uncharacterised, centrosome proteins, Cep70 and Cep131. The phenotype of these embryos resembles that of zebrafish mutants for intraflagellar transport proteins (IFTs), with kidney and ear development affected and left-right asymmetry randomised. These organs and processes are those affected in Bardet-Biedl syndrome and other similar diseases. Like these diseases, the root cause of the phenotype lies, in fact, in dysfunctional cilia, which are shortened but not eliminated in several tissues in the morphants. Centrosomes and basal bodies, on the other hand, are present. Both Cep70 and Cep131 possess a putative HDAC (histone deacetylase) interacting domain. However, we could not detect in yeast two-hybrid assays any interaction with the deacetylase that controls cilium length, HDAC6, or any of the IFTs that we tested.

Conclusion: Cep70 and Cep131 contribute to ciliogenesis in many tissues in the zebrafish embryo: cilia are made in cep70 and cep131 morphant zebrafish embryos but are shortened. We propose that the role of these centrosomal/basal body proteins is in making the cilium and that they are involved in determination of the length of the axoneme.

Show MeSH
Related in: MedlinePlus