Alternative titles; symbols
HGNC Approved Gene Symbol: CCDC65
Cytogenetic location: 12q13.12 Genomic coordinates (GRCh38): 12:48,904,133-48,921,576 (from NCBI)
| Location | Phenotype |
Phenotype MIM number |
Inheritance |
Phenotype mapping key |
|---|---|---|---|---|
| 12q13.12 | Ciliary dyskinesia, primary, 27 | 615504 | Autosomal recessive | 3 |
The CCDC65 gene encodes the human ortholog of Chlamydomonas reinhardtii DRC2, which is a component of the nexin-dynein regulatory complex (N-DRC), a structure important for regulating and orchestrating dynein activity (summary by Horani et al., 2013). CCDC65 is also a sperm tail protein that is posttranslationally modified during sperm capacitation (Zheng et al., 2006).
By differential display of genes upregulated in human adult versus fetal testis, Zheng et al. (2006) cloned CCDC65, which they called NYD-SP28. The deduced 484-amino acid protein has a calculated molecular mass of 57 kD and contains 2 potential sites for N-glycosylation, 2 for N-myristoylation, and many potential phosphorylation sites. Western blot analysis detected high CCDC65 expression in adult human testis, but no detectable expression in fetal testis. Immunohistochemical studies of CCDC65 expression in spermatozoa detected protein primarily in the spermatocyte and spermatid, with weak expression in spermatogonia and no signal in Leydig cells. Immunofluorescence analysis detected CCDC65 throughout the entire sperm tail in human noncapacitated, capacitated, and acrosome-reacted spermatozoa. Using 2-dimensional SDS-PAGE analysis of proteins from human noncapacitated and capacitated sperm extracts, Zheng et al. (2006) concluded that CCDC65 is posttranslationally modified during capacitation. Transfection experiments in 7721 cells localized CCDC65 to the cytoplasm.
Zheng et al. (2006) determined that the CCDC65 gene contains 8 exons spanning more than 17 kb.
By genomic sequence analysis, Zheng et al. (2006) mapped the CCDC65 gene to chromosome 12q13.12.
Austin-Tse et al. (2013) noted that the Chlamydomonas CCDC65 ortholog Fap250 is a subunit of the nexin-dynein regulatory complex. The Chlamydomonas ida6 motility mutant with inner arm dynein defects was rescued by transformation with Fap250, and a causative mutation was identified in the Fab250/Ccdc65 gene. Analysis of isolated ida6 axonemes showed defects in the assembly of both the inner dynein arms and the N-DRC. These data, together with the predicted size of the FAP250 polypeptide, strongly suggested that FAP250 corresponds to the DRC2 subunit of N-DRC and that DRC2/FAP250/CCDC65 plays a critical role in the assembly of the N-DRC.
Horani et al. (2013) found expression of CCDC65 during early ciliated cell differentiation in human tracheal airway epithelial cells, suggesting that it is associated with ciliogenesis. Expression of CCDC65 also increased significantly following deflagellation of C. reinhardtii.
In 3 Ashkenazi Jewish patients, including 2 brothers, with primary ciliary dyskinesia-27 (CILD27; 615504), Austin-Tse et al. (2013) identified a homozygous truncating mutation in the CCDC65 gene (611088.0001). The patients were ascertained from a larger cohort of 295 individuals with CILD. The patients had recurrent bronchitis, sinusitis, and/or otitis media, but no situs inversus. Fertility status could not be ascertained. Cilia ultrastructure showed normal outer dynein arms, radial spokes, and central pairs, but there was a reduction in inner dynein arms and nexin links. Microtubule disorganization was also observed in 5 to 15% of cilia cross-sections, suggesting that the reduction in nexin links may lead to overall structural instability in a subset of cilia. Live imaging of patient nasal epithelial cilia showed a stiff, dyskinetic cilia waveform.
Horani et al. (2013) also identified a homozygous truncating mutation in the CCDC65 gene (611088.0001) in a patient of Ashkenazi Jewish descent with CILD. The patient did not have laterality defects. Immunohistochemical studies of patient nasal epithelial cells showed absence of the CCDC65 protein as well as absence of GAS8 (605178), another member of the N-DRC. Similar results were obtained after shRNA knockdown of CCDC65 in control respiratory epithelial cells.
Austin-Tse et al. (2013) found that morpholino knockdown of the CCDC65 gene in zebrafish resulted in a strong ciliopathy phenotype, including pronephric cysts, axis curvature, left-right asymmetry defects, and hydrocephalus. Immunostaining for certain ciliary proteins did not detect structural abnormalities, and ultrastructure analysis showed that the outer dynein arms were not missing. High-speed video microscopy showed stiff, dyskinetic cilia, consistent with a motility defect.
In 2 brothers of Ashkenazi Jewish descent with primary ciliary dyskinesia-27 without situs inversus (CILD27; 615504), Austin-Tse et al. (2013) identified a homozygous 2-bp deletion, which they reported as 877_878delAT, in exon 6 of the CCDC65 gene, resulting in a frameshift and premature termination (Ile293ProfsTer2). An unrelated girl of Ashkenazi Jewish descent was also found to be homozygous for the mutation; her unaffected parents were heterozygous for the mutation. The patients had recurrent bronchitis, sinusitis, and/or otitis media. Fertility status could not be ascertained. Cilia ultrastructure showed normal outer dynein arms, radial spokes, and central pairs, but there was a reduction in inner dynein arms and nexin links. Microtubule disorganization was also observed in 5 to 15% of cilia cross-sections, suggesting that the reduction in nexin links may lead to overall structural instability in a subset of cilia. Live imaging of patient nasal epithelial cilia showed a stiff, dyskinetic cilia waveform.
Horani et al. (2013) identified a homozygous 2-bp deletion (c.876_877delAT) in exon 6 of the CCDC65 gene in an 18-year-old boy of Ashkenazi Jewish descent with CILD27 without situs inversus. The deletion was predicted to result in a frameshift and premature termination at codon 293. The mutation, which was found by a combination of homozygosity mapping and candidate gene sequencing, segregated with the disorder in the family and was not found in the dbSNP (build 135) or Exome Variant Server databases. It was found in 3 of 733 Ashkenazi Jewish controls, indicating a carrier rate of 1 in 244. Patient nasal epithelial cilia showed a normal structure, but an abnormal stiff and hyperkinetic beating pattern compared to controls. Immunohistochemical studies of patient nasal epithelial cells showed absence of the CCDC65 protein as well as absence of GAS8 (605178). Similar results were obtained after shRNA knockdown of CCDC65 in control respiratory epithelial cells.
Austin-Tse, C., Halbritter, J., Zariwala, M. A., Gilberti, R. M., Gee, H. Y., Hellman, N., Pathak, N., Liu, Y., Panizzi, J. R., Patel-King, R. S., Tritschler, D., Bower, R., and 31 others. Zebrafish ciliopathy screen plus human mutational analysis identifies C21orf59 and CCDC65 defects as causing primary ciliary dyskinesia. Am. J. Hum. Genet. 93: 672-686, 2013. [PubMed: 24094744] [Full Text: https://doi.org/10.1016/j.ajhg.2013.08.015]
Horani, A., Brody, S. L., Ferkol, T. W., Shoseyov, D., Wasserman, M. G., Ta-shma, A., Wilson, K. S., Bayly, P. V., Amirav, I., Cohen-Cymberknoh, M., Dutcher, S. K., Elpeleg, O., Kerem, E. CCDC65 mutation causes primary ciliary dyskinesia with normal ultrastructure and hyperkinetic cilia. PLoS One 8: e72299, 2013. Note: Electronic Article. [PubMed: 23991085] [Full Text: https://doi.org/10.1371/journal.pone.0072299]
Zheng, Y., Zhang, J., Wang, L., Zhou, Z., Xu, M., Li, J., Sha, J.-H. Cloning and characterization of a novel sperm tail protein, NYD-SP28. Int. J. Molec. Med. 18: 1119-1125, 2006. [PubMed: 17089017]