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Mutations in human C2CD3 cause skeletal dysplasia and provide new insights into phenotypic and cellular consequences of altered C2CD3 function.

Cortés CR, McInerney-Leo AM, Vogel I, Rondón Galeano MC, Leo PJ, Harris JE, Anderson LK, Keith PA, Brown MA, Ramsing M, Duncan EL, Zankl A, Wicking C - Sci Rep (2016)

Bottom Line: Ciliopathies are clinically grouped in a large number of overlapping disorders, including the orofaciodigital syndromes (OFDS), the short rib polydactyly syndromes and Jeune asphyxiating thoracic dystrophy.Analysis of fibroblast cultures derived from one of these fetuses revealed a reduced ability to form cilia, consistent with previous studies in C2cd3-mutant mouse and chicken cells.More detailed analyses support a role for C2CD3 in basal body maturation; but in contrast to previous mouse studies the normal recruitment of the distal appendage protein CEP164 suggests that this protein is not sufficient for efficient basal body maturation and subsequent axonemal extension in a C2CD3-defective background.

View Article: PubMed Central - PubMed

Affiliation: Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.

ABSTRACT
Ciliopathies are a group of genetic disorders caused by defective assembly or dysfunction of the primary cilium, a microtubule-based cellular organelle that plays a key role in developmental signalling. Ciliopathies are clinically grouped in a large number of overlapping disorders, including the orofaciodigital syndromes (OFDS), the short rib polydactyly syndromes and Jeune asphyxiating thoracic dystrophy. Recently, mutations in the gene encoding the centriolar protein C2CD3 have been described in two families with a new sub-type of OFDS (OFD14), with microcephaly and cerebral malformations. Here we describe a third family with novel compound heterozygous C2CD3 mutations in two fetuses with a different clinical presentation, dominated by skeletal dysplasia with no microcephaly. Analysis of fibroblast cultures derived from one of these fetuses revealed a reduced ability to form cilia, consistent with previous studies in C2cd3-mutant mouse and chicken cells. More detailed analyses support a role for C2CD3 in basal body maturation; but in contrast to previous mouse studies the normal recruitment of the distal appendage protein CEP164 suggests that this protein is not sufficient for efficient basal body maturation and subsequent axonemal extension in a C2CD3-defective background.

No MeSH data available.


Related in: MedlinePlus

Schematic model for C2CD3-deficient mouse and human cells.(a) In normal conditions, the centrosome moves to the cell surface and the mother centriole with subdistal and distal appendage proteins docks to the membrane. Prior to docking CP110 is removed from the distal end of the mother centriole, a step essential for axonemal extension. (b) In C2CD3-deficient mouse cells, the mother centriole does not form distal appendages or anchor to the plasma membrane, and shows defective removal of CP1102023. (c) In C2CD3-deficient human G3P1 cells, the subdistal and distal appendage proteins are localised normally at the mother centriole and basal body, but CP110 is not efficiently removed, hence blocking axonemal extension and ciliogenesis.
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f5: Schematic model for C2CD3-deficient mouse and human cells.(a) In normal conditions, the centrosome moves to the cell surface and the mother centriole with subdistal and distal appendage proteins docks to the membrane. Prior to docking CP110 is removed from the distal end of the mother centriole, a step essential for axonemal extension. (b) In C2CD3-deficient mouse cells, the mother centriole does not form distal appendages or anchor to the plasma membrane, and shows defective removal of CP1102023. (c) In C2CD3-deficient human G3P1 cells, the subdistal and distal appendage proteins are localised normally at the mother centriole and basal body, but CP110 is not efficiently removed, hence blocking axonemal extension and ciliogenesis.

Mentions: In terms of cellular phenotype, this is the first study to directly assess human cells harboring disease-causing mutations in C2CD3. Consistent with reported mouse and chick models202324, these cells ultimately have a defect in their ability to extend a primary cilium. In control cells centriolar appendages form, CP110 is removed from the mother centriole, and the axoneme is extended to form a functioning cilium (schematised in Fig. 5a)32. In addition to its role as a regulator of centriolar length, studies in mouse cells have determined that C2CD3 is required for proper distal appendage assembly, which in turn mediates ciliary vesicle docking, CP110 removal and recruitment of a sub-set of ciliary proteins2023. Accordingly, C2cd3-mutant mouse cells display defective centrosomal localisation of IFT88 and mother centriole uncapping, as well as mislocalisation of the sub-distal and distal appendage markers OFD2 and CEP164 (Fig. 5b), although in another study C2cd3Gt/Gt mouse cells display normal sub-distal appendages23. Whether the role of C2CD3 in centriolar elongation is related to distal appendage assembly, and hence underlies the ciliary defect in these cells is yet to be determined. Like both the C2cd3Hty/Hty and C2cd3Gt/Gt mouse cells, the human C2CD3-mutant fibroblasts in this study show inefficient removal of CP110 from the distal end of the mother centriole, and defective recruitment of the core IFT component IFT88 to the centrosome (Fig. 5c). However, in contrast to the mouse models, we find that centriolar appendage proteins CEP164 and ODF2 are localised normally to the mother centriole of most C2CD3-mutant human cells (Fig. 5c). This suggests that the presence of these proteins is not sufficient to allow correct localisation of IFT88 and removal of CP110 from the mother centriole in a C2CD3-mutant context. Given that CP110 removal is now thought to occur prior to docking of the mother centriole to the membrane and conversion to a basal body8, our data raise the possibility that the basal body may not be correctly docking to the membrane in most G3P1 cells, but this requires further analysis at the ultrastructural level.


Mutations in human C2CD3 cause skeletal dysplasia and provide new insights into phenotypic and cellular consequences of altered C2CD3 function.

Cortés CR, McInerney-Leo AM, Vogel I, Rondón Galeano MC, Leo PJ, Harris JE, Anderson LK, Keith PA, Brown MA, Ramsing M, Duncan EL, Zankl A, Wicking C - Sci Rep (2016)

Schematic model for C2CD3-deficient mouse and human cells.(a) In normal conditions, the centrosome moves to the cell surface and the mother centriole with subdistal and distal appendage proteins docks to the membrane. Prior to docking CP110 is removed from the distal end of the mother centriole, a step essential for axonemal extension. (b) In C2CD3-deficient mouse cells, the mother centriole does not form distal appendages or anchor to the plasma membrane, and shows defective removal of CP1102023. (c) In C2CD3-deficient human G3P1 cells, the subdistal and distal appendage proteins are localised normally at the mother centriole and basal body, but CP110 is not efficiently removed, hence blocking axonemal extension and ciliogenesis.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837335&req=5

f5: Schematic model for C2CD3-deficient mouse and human cells.(a) In normal conditions, the centrosome moves to the cell surface and the mother centriole with subdistal and distal appendage proteins docks to the membrane. Prior to docking CP110 is removed from the distal end of the mother centriole, a step essential for axonemal extension. (b) In C2CD3-deficient mouse cells, the mother centriole does not form distal appendages or anchor to the plasma membrane, and shows defective removal of CP1102023. (c) In C2CD3-deficient human G3P1 cells, the subdistal and distal appendage proteins are localised normally at the mother centriole and basal body, but CP110 is not efficiently removed, hence blocking axonemal extension and ciliogenesis.
Mentions: In terms of cellular phenotype, this is the first study to directly assess human cells harboring disease-causing mutations in C2CD3. Consistent with reported mouse and chick models202324, these cells ultimately have a defect in their ability to extend a primary cilium. In control cells centriolar appendages form, CP110 is removed from the mother centriole, and the axoneme is extended to form a functioning cilium (schematised in Fig. 5a)32. In addition to its role as a regulator of centriolar length, studies in mouse cells have determined that C2CD3 is required for proper distal appendage assembly, which in turn mediates ciliary vesicle docking, CP110 removal and recruitment of a sub-set of ciliary proteins2023. Accordingly, C2cd3-mutant mouse cells display defective centrosomal localisation of IFT88 and mother centriole uncapping, as well as mislocalisation of the sub-distal and distal appendage markers OFD2 and CEP164 (Fig. 5b), although in another study C2cd3Gt/Gt mouse cells display normal sub-distal appendages23. Whether the role of C2CD3 in centriolar elongation is related to distal appendage assembly, and hence underlies the ciliary defect in these cells is yet to be determined. Like both the C2cd3Hty/Hty and C2cd3Gt/Gt mouse cells, the human C2CD3-mutant fibroblasts in this study show inefficient removal of CP110 from the distal end of the mother centriole, and defective recruitment of the core IFT component IFT88 to the centrosome (Fig. 5c). However, in contrast to the mouse models, we find that centriolar appendage proteins CEP164 and ODF2 are localised normally to the mother centriole of most C2CD3-mutant human cells (Fig. 5c). This suggests that the presence of these proteins is not sufficient to allow correct localisation of IFT88 and removal of CP110 from the mother centriole in a C2CD3-mutant context. Given that CP110 removal is now thought to occur prior to docking of the mother centriole to the membrane and conversion to a basal body8, our data raise the possibility that the basal body may not be correctly docking to the membrane in most G3P1 cells, but this requires further analysis at the ultrastructural level.

Bottom Line: Ciliopathies are clinically grouped in a large number of overlapping disorders, including the orofaciodigital syndromes (OFDS), the short rib polydactyly syndromes and Jeune asphyxiating thoracic dystrophy.Analysis of fibroblast cultures derived from one of these fetuses revealed a reduced ability to form cilia, consistent with previous studies in C2cd3-mutant mouse and chicken cells.More detailed analyses support a role for C2CD3 in basal body maturation; but in contrast to previous mouse studies the normal recruitment of the distal appendage protein CEP164 suggests that this protein is not sufficient for efficient basal body maturation and subsequent axonemal extension in a C2CD3-defective background.

View Article: PubMed Central - PubMed

Affiliation: Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.

ABSTRACT
Ciliopathies are a group of genetic disorders caused by defective assembly or dysfunction of the primary cilium, a microtubule-based cellular organelle that plays a key role in developmental signalling. Ciliopathies are clinically grouped in a large number of overlapping disorders, including the orofaciodigital syndromes (OFDS), the short rib polydactyly syndromes and Jeune asphyxiating thoracic dystrophy. Recently, mutations in the gene encoding the centriolar protein C2CD3 have been described in two families with a new sub-type of OFDS (OFD14), with microcephaly and cerebral malformations. Here we describe a third family with novel compound heterozygous C2CD3 mutations in two fetuses with a different clinical presentation, dominated by skeletal dysplasia with no microcephaly. Analysis of fibroblast cultures derived from one of these fetuses revealed a reduced ability to form cilia, consistent with previous studies in C2cd3-mutant mouse and chicken cells. More detailed analyses support a role for C2CD3 in basal body maturation; but in contrast to previous mouse studies the normal recruitment of the distal appendage protein CEP164 suggests that this protein is not sufficient for efficient basal body maturation and subsequent axonemal extension in a C2CD3-defective background.

No MeSH data available.


Related in: MedlinePlus