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Tsutsumi R, Chaya T, Tsujii T, Furukawa T. The carboxyl-terminal region of SDCCAG8 comprises a functional module essential for cilia formation as well as organ development and homeostasis. J Biol Chem 2022; 298:101686. [PMID: 35131266 PMCID: PMC8902618 DOI: 10.1016/j.jbc.2022.101686] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/28/2022] [Accepted: 02/01/2022] [Indexed: 02/06/2023] Open
Abstract
In humans, ciliary dysfunction causes ciliopathies, which present as multiple organ defects, including developmental and sensory abnormalities. Sdccag8 is a centrosomal/basal body protein essential for proper cilia formation. Gene mutations in SDCCAG8 have been found in patients with ciliopathies manifesting a broad spectrum of symptoms, including hypogonadism. Among these mutations, several that are predicted to truncate the SDCCAG8 carboxyl (C) terminus are also associated with such symptoms; however, the underlying mechanisms are poorly understood. In the present study, we identified the Sdccag8 C-terminal region (Sdccag8-C) as a module that interacts with the ciliopathy proteins, Ick/Cilk1 and Mak, which were shown to be essential for the regulation of ciliary protein trafficking and cilia length in mammals in our previous studies. We found that Sdccag8-C is essential for Sdccag8 localization to centrosomes and cilia formation in cultured cells. We then generated a mouse mutant in which Sdccag8-C was truncated (Sdccag8ΔC/ΔC mice) using a CRISPR-mediated stop codon knock-in strategy. In Sdccag8ΔC/ΔC mice, we observed abnormalities in cilia formation and ciliopathy-like organ phenotypes, including cleft palate, polydactyly, retinal degeneration, and cystic kidney, which partially overlapped with those previously observed in Ick- and Mak-deficient mice. Furthermore, Sdccag8ΔC/ΔC mice exhibited a defect in spermatogenesis, which was a previously uncharacterized phenotype of Sdccag8 dysfunction. Together, these results shed light on the molecular and pathological mechanisms underlying ciliopathies observed in patients with SDCCAG8 mutations and may advance our understanding of protein–protein interaction networks involved in cilia development.
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Airik R, Slaats GG, Guo Z, Weiss AC, Khan N, Ghosh A, Hurd TW, Bekker-Jensen S, Schrøder JM, Elledge SJ, Andersen JS, Kispert A, Castelli M, Boletta A, Giles RH, Hildebrandt F. Renal-retinal ciliopathy gene Sdccag8 regulates DNA damage response signaling. J Am Soc Nephrol 2014; 25:2573-83. [PMID: 24722439 DOI: 10.1681/asn.2013050565] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Nephronophthisis-related ciliopathies (NPHP-RCs) are developmental and degenerative kidney diseases that are frequently associated with extrarenal pathologies such as retinal degeneration, obesity, and intellectual disability. We recently identified mutations in a gene encoding the centrosomal protein SDCCAG8 as causing NPHP type 10 in humans. To study the role of Sdccag8 in disease pathogenesis, we generated a Sdccag8 gene-trap mouse line. Homozygous Sdccag8(gt/gt) mice lacked the wild-type Sdccag8 transcript and protein, and recapitulated the human phenotypes of NPHP and retinal degeneration. These mice exhibited early onset retinal degeneration that was associated with rhodopsin mislocalization in the photoreceptors and reduced cone cell numbers, and led to progressive loss of vision. By contrast, renal histologic changes occurred later, and no global ciliary defects were observed in the kidneys. Instead, renal pathology was associated with elevated levels of DNA damage response signaling activity. Cell culture studies confirmed the aberrant activation of DNA damage response in Sdccag8(gt/gt)-derived cells, characterized by elevated levels of γH2AX and phosphorylated ATM and cell cycle profile abnormalities. Our analysis of Sdccag8(gt/gt) mice indicates that the pleiotropic phenotypes in these mice may arise through multiple tissue-specific disease mechanisms.
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Affiliation(s)
- Rannar Airik
- Division of Nephrology, Boston Children's Hospital, Boston, Massachusetts
| | - Gisela G Slaats
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Zhi Guo
- Department of Genetics, Harvard Medical School, Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts
| | - Anna-Carina Weiss
- Institute of Molecular Biology, Hannover Medical School, Hannover, Germany
| | - Naheed Khan
- Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan
| | - Amiya Ghosh
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Toby W Hurd
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh, United Kingdom
| | - Simon Bekker-Jensen
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jacob M Schrøder
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Steve J Elledge
- Department of Genetics, Harvard Medical School, Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts
| | - Jens S Andersen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Andreas Kispert
- Institute of Molecular Biology, Hannover Medical School, Hannover, Germany
| | - Maddalena Castelli
- Division of Genetics and Cell Biology, Dulbecco Telethon Institute, San Raffaele Scientific Institute, Milan, Italy; and
| | - Alessandra Boletta
- Division of Genetics and Cell Biology, Dulbecco Telethon Institute, San Raffaele Scientific Institute, Milan, Italy; and
| | - Rachel H Giles
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Friedhelm Hildebrandt
- Division of Nephrology, Boston Children's Hospital, Boston, Massachusetts; Howard Hughes Medical Institute, Chevy Chase, Maryland
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Tumor suppressor candidate TUSC3 expression during rat testis maturation. Biosci Biotechnol Biochem 2013; 77:2019-24. [PMID: 24096664 DOI: 10.1271/bbb.130327] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Analysis of microarray data obtained by comparing gene expression between 2-week-old infant and 7-week-old mature SD rat testes revealed novel targets involved in tumor suppression. Reverse-transcription polymerase chain reaction and Northern blotting indicated that Tusc3 gene expression was upregulated in the normal maturing testis and prostate and other organs such as the cerebrum and ovary. Tumor suppressor candidate 3 protein expression was detected in these same organs at a size of about 40 kDa, in accord with the predicted molecular size. In situ hybridization and immunohistochemistry showed that mRNA and protein localization were prevalent in the testis spermatocytes and interstitial cells such as the Leydig cells, as well as prostate epithelial cells. These data suggest that TUSC3 is deeply involved in spermatogenesis in the testis, inducing sperm differentiation and maturation, and plays a role in normal prostate development and tumor suppression.
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Regulation of rat tetratricopeptide repeat domain 29 gene expression by follicle-stimulating hormone. Biosci Biotechnol Biochem 2012; 76:1540-3. [PMID: 22878202 DOI: 10.1271/bbb.120293] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We screened the gene that encodes tetratricopeptide repeat domain 29 (Ttc29) in the maturing rat testis. Gene expression was determined by Northern blotting of 7-week-old rat testes, and a strong signal was detected close to the 18S rRNA band in addition to two weak high-molecular-weight signals. In situ hybridization revealed that Ttc29 was expressed primarily in the spermatocytes. We evaluated the effect of gonadotropin on Ttc29 expression using hypophysectomized rats. The pituitary was removed from 3-week-old rats, gonadotropin was injected at 5 weeks, and Ttc29 expression was determined at 7 weeks. Although testicular development and hyperplasia of interstitial cells were observed following chorionic gonadotropin treatment after hypophysectomy, Ttc29 expression was upregulated by treatment with follicle-stimulating hormone. Ttc29 encodes axonemal dynein, a component of sperm flagella. Taken together, these data indicate that axonemal dynein expression starts in the spermatocytes and is regulated by follicle-stimulating hormone.
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