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Srivastava S, Shaked HM, Gable K, Gupta SD, Pan X, Somashekarappa N, Han G, Mohassel P, Gotkine M, Doney E, Goldenberg P, Tan QKG, Gong Y, Kleinstiver B, Wishart B, Cope H, Pires CB, Stutzman H, Spillmann RC, Sadjadi R, Elpeleg O, Lee CH, Bellen HJ, Edvardson S, Eichler F, Dunn TM, Dai H, Dhar SU, Emrick LT, Goldman AM, Hanchard NA, Jamal F, Karaviti L, Lalani SR, Lee BH, Lewis RA, Marom R, Moretti PM, Murdock DR, Nicholas SK, Orengo JP, Posey JE, Potocki L, Rosenfeld JA, Samson SL, Scott DA, Tran AA, Vogel TP, Wangler MF, Yamamoto S, Eng CM, Liu P, Ward PA, Behrens E, Deardorff M, Falk M, Hassey K, Sullivan K, Vanderver A, Goldstein DB, Cope H, McConkie-Rosell A, Schoch K, Shashi V, Smith EC, Spillmann RC, Sullivan JA, Tan QKG, Walley NM, Agrawal PB, Beggs AH, Berry GT, Briere LC, Cobban LA, Coggins M, Cooper CM, Fieg EL, High F, Holm IA, Korrick S, Krier JB, Lincoln SA, Loscalzo J, Maas RL, MacRae CA, Pallais JC, Rao DA, Rodan LH, Silverman EK, Stoler JM, Sweetser DA, Walker M, Walsh CA, Esteves C, Kelley EG, Kohane IS, LeBlanc K, McCray AT, Nagy A, Dasari S, Lanpher BC, Lanza IR, Morava E, Oglesbee D, Bademci G, Barbouth D, Bivona S, Carrasquillo O, Chang TCP, Forghani I, Grajewski A, Isasi R, Lam B, Levitt R, Liu XZ, McCauley J, Sacco R, Saporta M, Schaechter J, Tekin M, Telischi F, Thorson W, Zuchner S, Colley HA, Dayal JG, Eckstein DJ, Findley LC, Krasnewich DM, Mamounas LA, Manolio TA, Mulvihill JJ, LaMoure GL, Goldrich MP, Urv TK, Doss AL, Acosta MT, Bonnenmann C, D’Souza P, Draper DD, Ferreira C, Godfrey RA, Groden CA, Macnamara EF, Maduro VV, Markello TC, Nath A, Novacic D, Pusey BN, Toro C, Wahl CE, Baker E, Burke EA, Adams DR, Gahl WA, Malicdan MCV, Tifft CJ, Wolfe LA, Yang J, Power B, Gochuico B, Huryn L, Latham L, Davis J, Mosbrook-Davis D, Rossignol F, Solomon B, MacDowall J, Thurm A, Zein W, Yousef M, Adam M, Amendola L, Bamshad M, Beck A, Bennett J, Berg-Rood B, Blue E, Boyd B, Byers P, Chanprasert S, Cunningham M, Dipple K, Doherty D, Earl D, Glass I, Golden-Grant K, Hahn S, Hing A, Hisama FM, Horike-Pyne M, Jarvik GP, Jarvik J, Jayadev S, Lam C, Maravilla K, Mefford H, Merritt JL, Mirzaa G, Nickerson D, Raskind W, Rosenwasser N, Scott CR, Sun A, Sybert V, Wallace S, Wener M, Wenger T, Ashley EA, Bejerano G, Bernstein JA, Bonner D, Coakley TR, Fernandez L, Fisher PG, Fresard L, Hom J, Huang Y, Kohler JN, Kravets E, Majcherska MM, Martin BA, Marwaha S, McCormack CE, Raja AN, Reuter CM, Ruzhnikov M, Sampson JB, Smith KS, Sutton S, Tabor HK, Tucker BM, Wheeler MT, Zastrow DB, Zhao C, Byrd WE, Crouse AB, Might M, Nakano-Okuno M, Whitlock J, Brown G, Butte MJ, Dell’Angelica EC, Dorrani N, Douine ED, Fogel BL, Gutierrez I, Huang A, Krakow D, Lee H, Loo SK, Mak BC, Martin MG, Martínez-Agosto JA, McGee E, Nelson SF, Nieves-Rodriguez S, Palmer CGS, Papp JC, Parker NH, Renteria G, Signer RH, Sinsheimer JS, Wan J, Wang LK, Perry KW, Woods JD, Alvey J, Andrews A, Bale J, Bohnsack J, Botto L, Carey J, Pace L, Longo N, Marth G, Moretti P, Quinlan A, Velinder M, Viskochi D, Bayrak-Toydemir P, Mao R, Westerfield M, Bican A, Brokamp E, Duncan L, Hamid R, Kennedy J, Kozuira M, Newman JH, PhillipsIII JA, Rives L, Robertson AK, Solem E, Cogan JD, Cole FS, Hayes N, Kiley D, Sisco K, Wambach J, Wegner D, Baldridge D, Pak S, Schedl T, Shin J, Solnica-Krezel L, Sadjadi R, Elpeleg O, Lee CH, Bellen HJ, Edvardson S, Eichler F, Dunn TM. SPTSSA variants alter sphingolipid synthesis and cause a complex hereditary spastic paraplegia. Brain 2023; 146:1420-1435. [PMID: 36718090 PMCID: PMC10319774 DOI: 10.1093/brain/awac460] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 11/03/2022] [Accepted: 11/19/2022] [Indexed: 02/01/2023] Open
Abstract
Sphingolipids are a diverse family of lipids with critical structural and signalling functions in the mammalian nervous system, where they are abundant in myelin membranes. Serine palmitoyltransferase, the enzyme that catalyses the rate-limiting reaction of sphingolipid synthesis, is composed of multiple subunits including an activating subunit, SPTSSA. Sphingolipids are both essential and cytotoxic and their synthesis must therefore be tightly regulated. Key to the homeostatic regulation are the ORMDL proteins that are bound to serine palmitoyltransferase and mediate feedback inhibition of enzymatic activity when sphingolipid levels become excessive. Exome sequencing identified potential disease-causing variants in SPTSSA in three children presenting with a complex form of hereditary spastic paraplegia. The effect of these variants on the catalytic activity and homeostatic regulation of serine palmitoyltransferase was investigated in human embryonic kidney cells, patient fibroblasts and Drosophila. Our results showed that two different pathogenic variants in SPTSSA caused a hereditary spastic paraplegia resulting in progressive motor disturbance with variable sensorineural hearing loss and language/cognitive dysfunction in three individuals. The variants in SPTSSA impaired the negative regulation of serine palmitoyltransferase by ORMDLs leading to excessive sphingolipid synthesis based on biochemical studies and in vivo studies in Drosophila. These findings support the pathogenicity of the SPTSSA variants and point to excessive sphingolipid synthesis due to impaired homeostatic regulation of serine palmitoyltransferase as responsible for defects in early brain development and function.
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Affiliation(s)
- Siddharth Srivastava
- Department of Neurology, Rosamund Stone Zander Translational Neuroscience Center, BostonChildren's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Hagar Mor Shaked
- Department of Genetics, Hadassah Medical Center and Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Kenneth Gable
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Sita D Gupta
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Xueyang Pan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Niranjanakumari Somashekarappa
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Gongshe Han
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Payam Mohassel
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20814, USA
| | - Marc Gotkine
- Department of Genetics, Hadassah Medical Center and Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | | | - Paula Goldenberg
- Department of Pediatrics, Section on Medical Genetics, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Queenie K G Tan
- Department of Pediatrics, Division of Medical Genetics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Yi Gong
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.,Center for Genomic Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Benjamin Kleinstiver
- Center for Genomic Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.,Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Pathology, Harvard Medical School, Boston, MA 02115, USA
| | - Brian Wishart
- Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Heidi Cope
- Department of Pediatrics, Division of Medical Genetics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Claudia Brito Pires
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.,Center for Genomic Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Hannah Stutzman
- Center for Genomic Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.,Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Rebecca C Spillmann
- Department of Pediatrics, Division of Medical Genetics, Duke University School of Medicine, Durham, NC 27710, USA
| | | | - Reza Sadjadi
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Orly Elpeleg
- Department of Genetics, Hadassah Medical Center and Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Chia-Hsueh Lee
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Simon Edvardson
- Pediatric Neurology Unit, Hadassah University Hospital, Mount Scopus, Jerusalem 91240, Israel
| | - Florian Eichler
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.,Center for Genomic Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Teresa M Dunn
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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- Department of Neurology, Massachusetts General Hospital, Harvard Medical School , Boston, MA 02114 , USA
| | - Orly Elpeleg
- Department of Genetics, Hadassah Medical Center and Faculty of Medicine, Hebrew University of Jerusalem , Jerusalem 91120 , Israel
| | - Chia-Hsueh Lee
- Department of Structural Biology, St. Jude Children’s Research Hospital , Memphis, TN 38105 , USA
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine , Houston, TX 77030 , USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital , Houston, TX 77030 , USA
| | - Simon Edvardson
- Pediatric Neurology Unit, Hadassah University Hospital, Mount Scopus , Jerusalem 91240 , Israel
| | - Florian Eichler
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School , Boston, MA 02114 , USA
- Center for Genomic Medicine, Massachusetts General Hospital, Harvard Medical School , Boston, MA 02114 , USA
| | - Teresa M Dunn
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences , Bethesda, MD 20814 , USA
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Morimoto M, Bhambhani V, Gazzaz N, Davids M, Sathiyaseelan P, Macnamara EF, Lange J, Lehman A, Zerfas PM, Murphy JL, Acosta MT, Wang C, Alderman E, Reichert S, Thurm A, Adams DR, Introne WJ, Gorski SM, Boerkoel CF, Gahl WA, Tifft CJ, Malicdan MCV, Baldridge D, Bale J, Bamshad M, Barbouth D, Bayrak-Toydemir P, Beck A, Beggs AH, Behrens E, Bejerano G, Bellen HJ, Bennett J, Berg-Rood B, Bernstein JA, Berry GT, Bican A, Bivona S, Blue E, Bohnsack J, Bonner D, Botto L, Boyd B, Briere LC, Brokamp E, Brown G, Burke EA, Burrage LC, Butte MJ, Byers P, Byrd WE, Carey J, Carrasquillo O, Cassini T, Chang TCP, Chanprasert S, Chao HT, Clark GD, Coakley TR, Cobban LA, Cogan JD, Coggins M, Cole FS, Colley HA, Cooper CM, Cope H, Craigen WJ, Crouse AB, Cunningham M, D’Souza P, Dai H, Dasari S, Davis J, Dayal JG, Dell’Angelica EC, Dipple K, Doherty D, Dorrani N, Doss AL, Douine ED, Duncan L, Earl D, Eckstein DJ, Emrick LT, Eng CM, Esteves C, Falk M, Fieg EL, Fisher PG, Fogel BL, Forghani I, Glass I, Gochuico B, Goddard PC, Godfrey RA, Golden-Grant K, Grajewski A, Gutierrez I, Hadley D, Hahn S, Halley MC, Hamid R, Hassey K, Hayes N, High F, Hing A, Hisama FM, Holm IA, Hom J, Horike-Pyne M, Huang A, Hutchison S, Introne WJ, Isasi R, Izumi K, Jamal F, Jarvik GP, Jarvik J, Jayadev S, Jean-Marie O, Jobanputra V, Karaviti L, Kennedy J, Ketkar S, Kiley D, Kilich G, Kobren SN, Kohane IS, Kohler JN, Korrick S, Kozuira M, Krakow D, Krasnewich DM, Kravets E, Lalani SR, Lam B, Lam C, Lanpher BC, Lanza IR, LeBlanc K, Lee BH, Levitt R, Lewis RA, Liu P, Liu XZ, Longo N, Loo SK, Loscalzo J, Maas RL, MacRae CA, Maduro VV, Mahoney R, Mak BC, Mamounas LA, Manolio TA, Mao R, Maravilla K, Marom R, Marth G, Martin BA, Martin MG, Martínez-Agosto JA, Marwaha S, McCauley J, McConkie-Rosell A, McCray AT, McGee E, Mefford H, Merritt JL, Might M, Mirzaa G, Morava E, Moretti P, Nakano-Okuno M, Nelson SF, Newman JH, Nicholas SK, Nickerson D, Nieves-Rodriguez S, Novacic D, Oglesbee D, Orengo JP, Pace L, Pak S, Pallais JC, Palmer CGS, Papp JC, Parker NH, Phillips JA, Posey JE, Potocki L, Pusey Swerdzewski BN, Quinlan A, Rao DA, Raper A, Raskind W, Renteria G, Reuter CM, Rives L, Robertson AK, Rodan LH, Rosenfeld JA, Rosenwasser N, Rossignol F, Ruzhnikov M, Sacco R, Sampson JB, Saporta M, Schaechter J, Schedl T, Schoch K, Scott DA, Scott CR, Shashi V, Shin J, Silverman EK, Sinsheimer JS, Sisco K, Smith EC, Smith KS, Solem E, Solnica-Krezel L, Solomon B, Spillmann RC, Stoler JM, Sullivan K, Sullivan JA, Sun A, Sutton S, Sweetser DA, Sybert V, Tabor HK, Tan QKG, Tan ALM, Tekin M, Telischi F, Thorson W, Toro C, Tran AA, Ungar RA, Urv TK, Vanderver A, Velinder M, Viskochil D, Vogel TP, Wahl CE, Walker M, Wallace S, Walley NM, Wambach J, Wan J, Wang LK, Wangler MF, Ward PA, Wegner D, Weisz Hubshman M, Wener M, Wenger T, Wesseling Perry K, Westerfield M, Wheeler MT, Whitlock J, Wolfe LA, Worley K, Xiao C, Yamamoto S, Yang J, Zhang Z, Zuchner S, Reichert S, Thurm A, Adams DR, Introne WJ, Gorski SM, Boerkoel CF, Gahl WA, Tifft CJ, Malicdan MCV. Bi-allelic ATG4D variants are associated with a neurodevelopmental disorder characterized by speech and motor impairment. NPJ Genom Med 2023; 8:4. [PMID: 36765070 PMCID: PMC9918471 DOI: 10.1038/s41525-022-00343-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 12/06/2022] [Indexed: 02/12/2023] Open
Abstract
Autophagy regulates the degradation of damaged organelles and protein aggregates, and is critical for neuronal development, homeostasis, and maintenance, yet few neurodevelopmental disorders have been associated with pathogenic variants in genes encoding autophagy-related proteins. We report three individuals from two unrelated families with a neurodevelopmental disorder characterized by speech and motor impairment, and similar facial characteristics. Rare, conserved, bi-allelic variants were identified in ATG4D, encoding one of four ATG4 cysteine proteases important for autophagosome biogenesis, a hallmark of autophagy. Autophagosome biogenesis and induction of autophagy were intact in cells from affected individuals. However, studies evaluating the predominant substrate of ATG4D, GABARAPL1, demonstrated that three of the four ATG4D patient variants functionally impair ATG4D activity. GABARAPL1 is cleaved or "primed" by ATG4D and an in vitro GABARAPL1 priming assay revealed decreased priming activity for three of the four ATG4D variants. Furthermore, a rescue experiment performed in an ATG4 tetra knockout cell line, in which all four ATG4 isoforms were knocked out by gene editing, showed decreased GABARAPL1 priming activity for the two ATG4D missense variants located in the cysteine protease domain required for priming, suggesting that these variants impair the function of ATG4D. The clinical, bioinformatic, and functional data suggest that bi-allelic loss-of-function variants in ATG4D contribute to the pathogenesis of this syndromic neurodevelopmental disorder.
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Affiliation(s)
- Marie Morimoto
- grid.94365.3d0000 0001 2297 5165National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, MD 20892 USA
| | - Vikas Bhambhani
- grid.418506.e0000 0004 0629 5022Department of Medical Genetics, Children’s Hospitals and Clinics of Minnesota, Minneapolis, MN 55404 USA
| | - Nour Gazzaz
- grid.17091.3e0000 0001 2288 9830Department of Medical Genetics, Faculty of Medicine, University of British Columbia, Vancouver, BC V6H 3N1 Canada ,grid.414137.40000 0001 0684 7788Provincial Medical Genetics Program, British Columbia Women’s and Children’s Hospital, Vancouver, BC V6H 3N1 Canada ,grid.412125.10000 0001 0619 1117Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mariska Davids
- grid.94365.3d0000 0001 2297 5165National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, MD 20892 USA
| | - Paalini Sathiyaseelan
- grid.434706.20000 0004 0410 5424Canada’s Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, BC V5Z 1L3 Canada ,grid.61971.380000 0004 1936 7494Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6 Canada
| | - Ellen F. Macnamara
- grid.94365.3d0000 0001 2297 5165National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, MD 20892 USA
| | | | - Anna Lehman
- grid.17091.3e0000 0001 2288 9830Department of Medical Genetics, Faculty of Medicine, University of British Columbia, Vancouver, BC V6H 3N1 Canada
| | - Patricia M. Zerfas
- grid.94365.3d0000 0001 2297 5165Diagnostic and Research Services Branch, Office of Research Services, National Institutes of Health, Bethesda, MD 20892 USA
| | - Jennifer L. Murphy
- grid.94365.3d0000 0001 2297 5165National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, MD 20892 USA
| | - Maria T. Acosta
- grid.94365.3d0000 0001 2297 5165National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, MD 20892 USA
| | - Camille Wang
- grid.94365.3d0000 0001 2297 5165National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, MD 20892 USA
| | - Emily Alderman
- grid.17091.3e0000 0001 2288 9830Department of Medical Genetics, Faculty of Medicine, University of British Columbia, Vancouver, BC V6H 3N1 Canada ,grid.414137.40000 0001 0684 7788Provincial Medical Genetics Program, British Columbia Women’s and Children’s Hospital, Vancouver, BC V6H 3N1 Canada
| | | | - Sara Reichert
- grid.418506.e0000 0004 0629 5022Department of Medical Genetics, Children’s Hospitals and Clinics of Minnesota, Minneapolis, MN 55404 USA
| | - Audrey Thurm
- grid.94365.3d0000 0001 2297 5165Neurodevelopmental and Behavioral Phenotyping Service, Office of the Clinical Director, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892 USA
| | - David R. Adams
- grid.94365.3d0000 0001 2297 5165National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, MD 20892 USA ,grid.94365.3d0000 0001 2297 5165Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - Wendy J. Introne
- grid.94365.3d0000 0001 2297 5165National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, MD 20892 USA ,grid.94365.3d0000 0001 2297 5165Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892 USA ,grid.94365.3d0000 0001 2297 5165Human Biochemical Genetics Section, Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - Sharon M. Gorski
- grid.17091.3e0000 0001 2288 9830Department of Medical Genetics, Faculty of Medicine, University of British Columbia, Vancouver, BC V6H 3N1 Canada ,grid.434706.20000 0004 0410 5424Canada’s Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, BC V5Z 1L3 Canada ,grid.61971.380000 0004 1936 7494Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6 Canada
| | - Cornelius F. Boerkoel
- grid.17091.3e0000 0001 2288 9830Department of Medical Genetics, Faculty of Medicine, University of British Columbia, Vancouver, BC V6H 3N1 Canada ,grid.414137.40000 0001 0684 7788Provincial Medical Genetics Program, British Columbia Women’s and Children’s Hospital, Vancouver, BC V6H 3N1 Canada
| | - William A. Gahl
- grid.94365.3d0000 0001 2297 5165National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, MD 20892 USA ,grid.94365.3d0000 0001 2297 5165Human Biochemical Genetics Section, Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - Cynthia J. Tifft
- grid.94365.3d0000 0001 2297 5165National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, MD 20892 USA ,grid.94365.3d0000 0001 2297 5165Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - May Christine V. Malicdan
- grid.94365.3d0000 0001 2297 5165National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, MD 20892 USA ,grid.94365.3d0000 0001 2297 5165Human Biochemical Genetics Section, Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892 USA
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Miller IM, Yashar BM, Macnamara EF, Adams DR, Agrawal PB, Alvey J, Amendola L, Andrews A, Ashley EA, Azamian MS, Bacino CA, Bademci G, Baker E, Balasubramanyam A, Baldridge D, Bale J, Bamshad M, Barbouth D, Bayrak-Toydemir P, Beck A, Beggs AH, Behrens E, Bejerano G, Bellen HJ, Bennett J, Berg-Rood B, Bernstein JA, Berry GT, Bican A, Bivona S, Blue E, Bohnsack J, Bonnenmann C, Bonner D, Botto L, Boyd B, Briere LC, Brokamp E, Brown G, Burke EA, Burrage LC, Butte MJ, Byers P, Byrd WE, Carey J, Carrasquillo O, Chang TCP, Chanprasert S, Chao HT, Clark GD, Coakley TR, Cobban LA, Cogan JD, Coggins M, Cole FS, Colley HA, Cooper CM, Cope H, Craigen WJ, Crouse AB, Cunningham M, D’Souza P, Dai H, Dasari S, Davis J, Dayal JG, Dell’Angelica EC, Dipple K, Doherty D, Dorrani N, Doss AL, Douine ED, Draper DD, Duncan L, Earl D, Eckstein DJ, Emrick LT, Eng CM, Esteves C, Falk M, Fernandez L, Ferreira C, Fieg EL, Findley LC, Fisher PG, Fogel BL, Forghani I, Gahl WA, Glass I, Gochuico B, Godfrey RA, Golden-Grant K, Goldrich MP, Goldstein DB, Grajewski A, Groden CA, Gutierrez I, Hahn S, Hamid R, Hassey K, Hayes N, High F, Hing A, Hisama FM, Holm IA, Hom J, Horike-Pyne M, Huang Y, Huang A, Huryn L, Isasi R, Izumi K, Jamal F, Jarvik GP, Jarvik J, Jayadev S, Karaviti L, Kennedy J, Ketkar S, Kiley D, Kilich G, Kobren SN, Kohane IS, Kohler JN, Korrick S, Kozuira M, Krakow D, Krasnewich DM, Kravets E, Krier JB, Lalani SR, Lam B, Lam C, LaMoure GL, Lanpher BC, Lanza IR, Latham L, LeBlanc K, Lee BH, Lee H, Levitt R, Lewis RA, Lincoln SA, Liu P, Liu XZ, Longo N, Loo SK, Loscalzo J, Maas RL, MacDowall J, Macnamara EF, MacRae CA, Maduro VV, Mahoney R, Mak BC, Malicdan MCV, Mamounas LA, Manolio TA, Mao R, Maravilla K, Markello TC, Marom R, Marth G, Martin BA, Martin MG, Martfnez-Agosto JA, Marwaha S, McCauley J, McConkie-Rosell A, McCray AT, McGee E, Mefford H, Merritt JL, Might M, Mirzaa G, Morava E, Moretti PM, Moretti P, Mosbrook-Davis D, Mulvihill JJ, Nakano-Okuno M, Nath A, Nelson SF, Newman JH, Nicholas SK, Nickerson D, Nieves-Rodriguez S, Novacic D, Oglesbee D, Orengo JP, Pace L, Pak S, Pallais JC, Palmer CGS, Papp JC, Parker NH, Phillips JA, Posey JE, Potocki L, Power B, Pusey BN, Quinlan A, Raja AN, Rao DA, Raper A, Raskind W, Renteria G, Reuter CM, Rives L, Robertson AK, Rodan LH, Rosenfeld JA, Rosenwasser N, Rossignol F, Ruzhnikov M, Sacco R, Sampson JB, Saporta M, Schaechter J, Schedl T, Schoch K, Scott DA, Scott CR, Shashi V, Shin J, Signer RH, Silverman EK, Sinsheimer JS, Sisco K, Smith EC, Smith KS, Solem E, Solnica-Krezel L, Solomon B, Spillmann RC, Stoler JM, Sullivan K, Sullivan JA, Sun A, Sutton S, Sweetser DA, Sybert V, Tabor HK, Tan QKG, Tan ALM, Tekin M, Telischi F, Thorson W, Thurm A, Tifft CJ, Toro C, Tran AA, Tucker BM, Urv TK, Vanderver A, Velinder M, Viskochil D, Vogel TP, Wahl CE, Walker M, Wallace S, Walley NM, Walsh CA, Wambach J, Wan J, Wang LK, Wangler MF, Ward PA, Wegner D, Hubshman MW, Wener M, Wenger T, Perry KW, Westerfield M, Wheeler MT, Whitlock J, Wolfe LA, Woods JD, Worley K, Yamamoto S, Yang J, Yousef M, Zastrow DB, Zein W, Zhang Z, Zhao C, Zuchner S, Macnamara EF. Continuing a search for a diagnosis: the impact of adolescence and family dynamics. Orphanet J Rare Dis 2023; 18:6. [PMID: 36624503 PMCID: PMC9830697 DOI: 10.1186/s13023-022-02598-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 12/14/2022] [Indexed: 01/11/2023] Open
Abstract
The "diagnostic odyssey" describes the process those with undiagnosed conditions undergo to identify a diagnosis. Throughout this process, families of children with undiagnosed conditions have multiple opportunities to decide whether to continue or stop their search for a diagnosis and accept the lack of a diagnostic label. Previous studies identified factors motivating a family to begin searching, but there is limited information about the decision-making process in a prolonged search and how the affected child impacts a family's decision. This study aimed to understand how families of children with undiagnosed diseases decide whether to continue to pursue a diagnosis after standard clinical testing has failed. Parents who applied to the Undiagnosed Disease Network (UDN) at the National Institutes of Health (NIH) were recruited to participate in semi-structured interviews. The 2015 Supportive Care Needs model by Pelenstov, which defines critical needs in families with rare/undiagnosed diseases, provided a framework for interview guide development and transcript analysis (Pelentsov et al in Disabil Health J 8(4):475-491, 2015. https://doi.org/10.1016/J.DHJO.2015.03.009 ). A deductive, iterative coding approach was used to identify common unifying themes. Fourteen parents from 13 families were interviewed. The average child's age was 11 years (range 3-18) and an average 63% of their life had been spent searching for a diagnosis. Our analysis found that alignment or misalignment of parent and child needs impact the trajectory of the diagnostic search. When needs and desires align, reevaluation of a decision to pursue a diagnosis is limited. However, when there is conflict between parent and child desires, there is reevaluation, and often a pause, in the search. This tension is exacerbated when children are adolescents and attempting to balance their dependence on parents for medical care with a natural desire for independence. Our results provide novel insights into the roles of adolescents in the diagnostic odyssey. The tension between desired and realistic developmental outcomes for parents and adolescents impacts if, and how, the search for a diagnosis progresses.
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Affiliation(s)
- Ilana M. Miller
- grid.239560.b0000 0004 0482 1586Children’s National Medical Center, Rare Disease Institute, 7125 13th Place NW, DC 20012 Washington, USA ,grid.214458.e0000000086837370Department of Human Genetics, University of Michigan, 4909 Buhl Building, Catherine St, Ann Arbor, MI 48109 USA
| | - Beverly M. Yashar
- grid.214458.e0000000086837370Department of Human Genetics, University of Michigan, 4909 Buhl Building, Catherine St, Ann Arbor, MI 48109 USA
| | | | - Ellen F. Macnamara
- grid.453125.40000 0004 0533 8641National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, NIH, Bethesda, MD USA
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Mao D, Reuter CM, Ruzhnikov MR, Beck AE, Farrow EG, Emrick LT, Rosenfeld JA, Mackenzie KM, Robak L, Wheeler MT, Burrage LC, Jain M, Liu P, Calame D, Küry S, Sillesen M, Schmitz-Abe K, Tonduti D, Spaccini L, Iascone M, Genetti CA, Koenig MK, Graf M, Tran A, Alejandro M, Lee BH, Thiffault I, Agrawal PB, Bernstein JA, Bellen HJ, Chao HT, Acosta MT, Adam M, Adams DR, Agrawal PB, Alejandro ME, Allard P, Alvey J, Amendola L, Andrews A, Ashley EA, Azamian MS, Bacino CA, Bademci G, Baker E, Balasubramanyam A, Baldridge D, Bale J, Bamshad M, Barbouth D, Batzli GF, Bayrak-Toydemir P, Beck A, Beggs AH, Bejerano G, Bellen HJ, Bennet J, Berg-Rood B, Bernier R, Bernstein JA, Berry GT, Bican A, Bivona S, Blue E, Bohnsack J, Bonnenmann C, Bonner D, Botto L, Briere LC, Brokamp E, Burke EA, Burrage LC, Butte MJ, Byers P, Carey J, Carrasquillo O, Chang TCP, Chanprasert S, Chao HT, Clark GD, Coakley TR, Cobban LA, Cogan JD, Cole FS, Colley HA, Cooper CM, Cope H, Craigen WJ, Cunningham M, D’Souza P, Dai H, Dasari S, Davids M, Dayal JG, Dell’Angelica EC, Dhar SU, Dipple K, Doherty D, Dorrani N, Douine ED, Draper DD, Duncan L, Earl D, Eckstein DJ, Emrick LT, Eng CM, Esteves C, Estwick T, Fernandez L, Ferreira C, Fieg EL, Fisher PG, Fogel BL, Forghani I, Fresard L, Gahl WA, Glass I, Godfrey RA, Golden-Grant K, Goldman AM, Goldstein DB, Grajewski A, Groden CA, Gropman AL, Hahn S, Hamid R, Hanchard NA, Hayes N, High F, Hing A, Hisama FM, Holm IA, Hom J, Horike-Pyne M, Huang A, Huang Y, Isasi R, Jamal F, Jarvik GP, Jarvik J, Jayadev S, Jiang YH, Johnston JM, Karaviti L, Kelley EG, Kiley D, Kohane IS, Kohler JN, Krakow D, Krasnewich DM, Korrick S, Koziura M, Krier JB, Lalani SR, Lam B, Lam C, Lanpher BC, Lanza IR, Lau CC, LeBlanc K, Lee BH, Lee H, Levitt R, Lewis RA, Lincoln SA, Liu P, Liu XZ, Longo N, Loo SK, Loscalzo J, Maas RL, Macnamara EF, MacRae CA, Maduro VV, Majcherska MM, Malicdan MCV, Mamounas LA, Manolio TA, Mao R, Maravilla K, Markello TC, Marom R, Marth G, Martin BA, Martin MG, Martínez-Agosto JA, Marwaha S, McCauley J, McConkie-Rosell A, McCormack CE, McCray AT, Mefford H, Merritt JL, Might M, Mirzaa G, Morava-Kozicz E, Moretti PM, Morimoto M, Mulvihill JJ, Murdock DR, Nath A, Nelson SF, Newman JH, Nicholas SK, Nickerson D, Novacic D, Oglesbee D, Orengo JP, Pace L, Pak S, Pallais JC, Palmer CG, Papp JC, Parker NH, Phillips JA, Posey JE, Postlethwait JH, Potocki L, Pusey BN, Quinlan A, Raskind W, Raja AN, Renteria G, Reuter CM, Rives L, Robertson AK, Rodan LH, Rosenfeld JA, Rowley RK, Ruzhnikov M, Sacco R, Sampson JB, Samson SL, Saporta M, Scott CR, Schaechter J, Schedl T, Schoch K, Scott DA, Shakachite L, Sharma P, Shashi V, Shin J, Signer R, Sillari CH, Silverman EK, Sinsheimer JS, Sisco K, Smith KS, Solnica-Krezel L, Spillmann RC, Stoler JM, Stong N, Sullivan JA, Sun A, Sutton S, Sweetser DA, Sybert V, Tabor HK, Tamburro CP, Tan QKG, Tekin M, Telischi F, Thorson W, Tifft CJ, Toro C, Tran AA, Urv TK, Velinder M, Viskochil D, Vogel TP, Wahl CE, Wallace S, Walley NM, Walsh CA, Walker M, Wambach J, Wan J, Wang LK, Wangler MF, Ward PA, Wegner D, Wener M, Westerfield M, Wheeler MT, Wise AL, Wolfe LA, Woods JD, Yamamoto S, Yang J, Yoon AJ, Yu G, Zastrow DB, Zhao C, Zuchner S. De novo EIF2AK1 and EIF2AK2 Variants Are Associated with Developmental Delay, Leukoencephalopathy, and Neurologic Decompensation. Am J Hum Genet 2020; 106:570-583. [PMID: 32197074 PMCID: PMC7118694 DOI: 10.1016/j.ajhg.2020.02.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 02/28/2020] [Indexed: 02/03/2023] Open
Abstract
EIF2AK1 and EIF2AK2 encode members of the eukaryotic translation initiation factor 2 alpha kinase (EIF2AK) family that inhibits protein synthesis in response to physiologic stress conditions. EIF2AK2 is also involved in innate immune response and the regulation of signal transduction, apoptosis, cell proliferation, and differentiation. Despite these findings, human disorders associated with deleterious variants in EIF2AK1 and EIF2AK2 have not been reported. Here, we describe the identification of nine unrelated individuals with heterozygous de novo missense variants in EIF2AK1 (1/9) or EIF2AK2 (8/9). Features seen in these nine individuals include white matter alterations (9/9), developmental delay (9/9), impaired language (9/9), cognitive impairment (8/9), ataxia (6/9), dysarthria in probands with verbal ability (6/9), hypotonia (7/9), hypertonia (6/9), and involuntary movements (3/9). Individuals with EIF2AK2 variants also exhibit neurological regression in the setting of febrile illness or infection. We use mammalian cell lines and proband-derived fibroblasts to further confirm the pathogenicity of variants in these genes and found reduced kinase activity. EIF2AKs phosphorylate eukaryotic translation initiation factor 2 subunit 1 (EIF2S1, also known as EIF2α), which then inhibits EIF2B activity. Deleterious variants in genes encoding EIF2B proteins cause childhood ataxia with central nervous system hypomyelination/vanishing white matter (CACH/VWM), a leukodystrophy characterized by neurologic regression in the setting of febrile illness and other stressors. Our findings indicate that EIF2AK2 missense variants cause a neurodevelopmental syndrome that may share phenotypic and pathogenic mechanisms with CACH/VWM.
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Wiederkehr C, Basavaraj R, Sarrauste de Menthière C, Hermida L, Koch R, Schlecht U, Amon A, Brachat S, Breitenbach M, Briza P, Caburet S, Cherry M, Davis R, Deutschbauer A, Dickinson HG, Dumitrescu T, Fellous M, Goldman A, Grootegoed JA, Hawley R, Ishii R, Jégou B, Kaufman RJ, Klein F, Lamb N, Maro B, Nasmyth K, Nicolas A, Orr-Weaver T, Philippsen P, Pineau C, Rabitsch KP, Reinke V, Roest H, Saunders W, Schröder M, Schedl T, Siep M, Villeneuve A, Wolgemuth DJ, Yamamoto M, Zickler D, Esposito RE, Primig M. GermOnline, a cross-species community knowledgebase on germ cell differentiation. Nucleic Acids Res 2004; 32:D560-7. [PMID: 14681481 PMCID: PMC308789 DOI: 10.1093/nar/gkh055] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
GermOnline provides information and microarray expression data for genes involved in mitosis and meiosis, gamete formation and germ line development across species. The database has been developed, and is being curated and updated, by life scientists in cooperation with bioinformaticists. Information is contributed through an online form using free text, images and the controlled vocabulary developed by the GeneOntology Consortium. Authors provide up to three references in support of their contribution. The database is governed by an international board of scientists to ensure a standardized data format and the highest quality of GermOnline's information content. Release 2.0 provides exclusive access to microarray expression data from Saccharomyces cerevisiae and Rattus norvegicus, as well as curated information on approximately 700 genes from various organisms. The locus report pages include links to external databases that contain relevant annotation, microarray expression and proteome data. Conversely, the Saccharomyces Genome Database (SGD), S.cerevisiae GeneDB and Swiss-Prot link to the budding yeast section of GermOnline from their respective locus pages. GermOnline, a fully operational prototype subject-oriented knowledgebase designed for community annotation and array data visualization, is accessible at http://www.germonline.org. The target audience includes researchers who work on mitotic cell division, meiosis, gametogenesis, germ line development, human reproductive health and comparative genomics.
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Affiliation(s)
- C Wiederkehr
- Biozentrum and Swiss Institute of Bioinformatics, Basel, Switzerland
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6
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Primig M, Wiederkehr C, Basavaraj R, Sarrauste de Menthière C, Hermida L, Koch R, Schlecht U, Dickinson HG, Fellous M, Grootegoed JA, Hawley RS, Jégou B, Maro B, Nicolas A, Orr-Weaver T, Schedl T, Villeneuve A, Wolgemuth DJ, Yamamoto M, Zickler D, Lamb N, Esposito RE. GermOnline, a new cross-species community annotation database on germ-line development and gametogenesis. Nat Genet 2004; 35:291-2. [PMID: 14647278 DOI: 10.1038/ng1203-291] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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7
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Gumienny TL, Brugnera E, Tosello-Trampont AC, Kinchen JM, Haney LB, Nishiwaki K, Walk SF, Nemergut ME, Macara IG, Francis R, Schedl T, Qin Y, Van Aelst L, Hengartner MO, Ravichandran KS. CED-12/ELMO, a novel member of the CrkII/Dock180/Rac pathway, is required for phagocytosis and cell migration. Cell 2001; 107:27-41. [PMID: 11595183 DOI: 10.1016/s0092-8674(01)00520-7] [Citation(s) in RCA: 445] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The C. elegans genes ced-2, ced-5, and ced-10, and their mammalian homologs crkII, dock180, and rac1, mediate cytoskeletal rearrangements during phagocytosis of apoptotic cells and cell motility. Here, we describe an additional member of this signaling pathway, ced-12, and its mammalian homologs, elmo1 and elmo2. In C. elegans, CED-12 is required for engulfment of dying cells and for cell migrations. In mammalian cells, ELMO1 functionally cooperates with CrkII and Dock180 to promote phagocytosis and cell shape changes. CED-12/ELMO-1 binds directly to CED-5/Dock180; this evolutionarily conserved complex stimulates a Rac-GEF, leading to Rac1 activation and cytoskeletal rearrangements. These studies identify CED-12/ELMO as an upstream regulator of Rac1 that affects engulfment and cell migration from C. elegans to mammals.
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Affiliation(s)
- T L Gumienny
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11743, USA
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8
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Abstract
Caenorhabditis elegans GLD-1, a KH motif containing RNA-binding protein of the GSG/STAR subfamily, controls diverse aspects of germ line development, suggesting that it may have multiple mRNA targets. We used an immunoprecipitation/subtractive hybridization/cloning strategy to identify 15 mRNAs that are putative targets of GLD-1 binding and regulation. For one target, the rme-2 yolk receptor mRNA, GLD-1 acts as a translational repressor to spatially restrict RME-2 accumulation, and thus yolk uptake, to late-stage oocytes. We found that GLD-1 binds sequences in both 5' coding and the 3' untranslated region of rme-2 mRNA. Initial characterization of the other 14 targets shows that (1) they are coexpressed with GLD-1; (2) they can have mutant/RNA-mediated interference depletion phenotypes indicating functions in germ line development or as maternal products necessary for early embryogenesis; and (3) GLD-1 may coregulate mRNAs corresponding to functionally redundant subsets of genes within two gene families. Thus, a diverse set of genes have come under GLD-1-mediated regulation to achieve normal germ line development. Previous work identified tra-2 as a GLD-1 target for germ line sex determination. Comparisons of GLD-1-mediated translational control of rme-2 and tra-2 suggests that the mechanisms may differ for distinct target mRNA species.
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Affiliation(s)
- M H Lee
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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9
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Miller MA, Nguyen VQ, Lee MH, Kosinski M, Schedl T, Caprioli RM, Greenstein D. A sperm cytoskeletal protein that signals oocyte meiotic maturation and ovulation. Science 2001; 291:2144-7. [PMID: 11251118 DOI: 10.1126/science.1057586] [Citation(s) in RCA: 301] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Caenorhabditis elegans oocytes, like those of most animals, arrest during meiotic prophase. Sperm promote the resumption of meiosis (maturation) and contraction of smooth muscle-like gonadal sheath cells, which are required for ovulation. We show that the major sperm cytoskeletal protein (MSP) is a bipartite signal for oocyte maturation and sheath contraction. MSP also functions in sperm locomotion, playing a role analogous to actin. Thus, during evolution, MSP has acquired extracellular signaling and intracellular cytoskeletal functions for reproduction. Proteins with MSP-like domains are found in plants, fungi, and other animals, suggesting that related signaling functions may exist in other phyla.
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Affiliation(s)
- M A Miller
- Department of Cell Biology, Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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Abstract
Germ cells are essential for reproduction, yet the molecular mechanisms that underlie their unique development are only beginning to be understood. Here we review important events that lead to the establishment of the germline and the initiation of meiotic development in C. elegans. Formation of the germline begins in the pregastrulation embryo, where it depends on polarization along the anterior/posterior axis and on the asymmetric segregation of P granules and associated factors. During postembryonic development, the germline expands using the GLP-1/Notch signaling pathway to promote proliferation and regulate entry into meiosis. Throughout their development, germ cells also employ unique "silencing" mechanisms to regulate their genome and protect themselves against unwanted expression from repetitive sequences including transposable elements. Together these mechanisms preserve the health and reproductive potential of the germline.
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Affiliation(s)
- G Seydoux
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
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11
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Clifford R, Lee MH, Nayak S, Ohmachi M, Giorgini F, Schedl T. FOG-2, a novel F-box containing protein, associates with the GLD-1 RNA binding protein and directs male sex determination in the C. elegans hermaphrodite germline. Development 2000; 127:5265-76. [PMID: 11076749 DOI: 10.1242/dev.127.24.5265] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Male sex determination in the Caenorhabditis elegans hermaphrodite germline requires translational repression of tra-2 mRNA by the GLD-1 RNA binding protein. We cloned fog-2 by finding that its gene product physically interacts with GLD-1, forming a FOG-2/GLD-1/tra-2 3′untranslated region ternary complex. FOG-2 has an N-terminal F-box and a novel C-terminal domain called FTH. Canonical F-box proteins act as bridging components of the SCF ubiquitin ligase complex; the N-terminal F-box binds a Skp1 homolog, recruiting ubiquination machinery, while a C-terminal protein-protein interaction domain binds a specific substrate for degradation. However, since both fog-2 and gld-1 are necessary for spermatogenesis, FOG-2 cannot target GLD-1 for ubiquitin-mediated degradation. We propose that FOG-2 also acts as a bridge, bringing GLD-1 bound to tra-2 mRNA into a multiprotein translational repression complex, thus representing a novel function for an F-box protein. fog-2 is a member of a large, apparently rapidly evolving, C. elegans gene family that has expanded, in part, by local duplications; fog-2 related genes have not been found outside nematodes. fog-2 may have arisen during evolution of self-fertile hermaphroditism from an ancestral female/male species.
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Affiliation(s)
- R Clifford
- Department of Genetics, Washington University School of Medicine, Campus Box 8232, St Louis, MO 63110, USA
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12
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Kuwabara PE, Lee MH, Schedl T, Jefferis GS. A C. elegans patched gene, ptc-1, functions in germ-line cytokinesis. Genes Dev 2000; 14:1933-44. [PMID: 10921907 PMCID: PMC316821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Patched (Ptc), initially identified in Drosophila, defines a class of multipass membrane proteins that control cell fate and cell proliferation. Biochemical studies in vertebrates indicate that the membrane proteins Ptc and Smoothened (Smo) form a receptor complex that binds Hedgehog (Hh) morphogens. Smo transduces the Hh signal to downstream effectors. The Caenorhabditis elegans genome encodes two Ptc homologs and one related pseudogene but does not encode obvious Hh or Smo homologs. We have analyzed ptc-1 by RNAi and mutational deletion and find that it is an essential gene, although the absence of ptc-1 has no detectable effect on body patterning or proliferation. Therefore, the C. elegans ptc-1 gene is functional despite the lack of Hh and Smo homologs. We find that the activity and expression of ptc-1 is essentially confined to the germ line and its progenitors. ptc-1 null mutants are sterile with multinucleate germ cells arising from a probable cytokinesis defect. We have also identified a surprisingly large family of PTC-related proteins containing sterol-sensing domains, including homologs of Drosophila dispatched, in C. elegans and other phyla. These results suggest that the PTC superfamily has multiple functions in animal development.
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Affiliation(s)
- P E Kuwabara
- The Sanger Centre, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK.
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Abstract
Prior to fertilization, oocytes undergo meiotic maturation (cell cycle progression) and ovulation (expulsion from the ovary). To begin the study of these processes in Caenorhabditis elegans, we have defined a time line of germline and somatic events by video microscopy. As the oocyte matures, its nuclear envelope breaks down and its cell cortex rearranges. Immediately thereafter, the oocyte is ovulated by increasing contraction of the myoepithelial gonadal sheath and relaxation of the distal spermatheca. By systematically altering the germ cell contents of the hermaphrodite using mutant strains, we have uncovered evidence of four cell-cell interactions that regulate maturation and ovulation. (1) Both spermatids and spermatozoa induce oocyte maturation. In animals with a feminized germline, maturation is inhibited and oocytes arrest in diakinesis. The introduction of sperm by mating restores maturation. (2) Sperm also directly promote sheath contraction. In animals with a feminized or tumorous germline, contractions are infrequent, whereas in animals with a masculinized germline or with sperm introduced by mating, contractions are frequent. (3 and 4) The maturing oocyte both induces spermathecal dilation and modulates sheath contractions at ovulation; dilation of the distal spermatheca and sharp increases in sheath contraction rates are only observed in the presence of a maturing oocyte.
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Affiliation(s)
- J McCarter
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
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14
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Berry LW, Westlund B, Schedl T. Germ-line tumor formation caused by activation of glp-1, a Caenorhabditis elegans member of the Notch family of receptors. Development 1997; 124:925-36. [PMID: 9043073 DOI: 10.1242/dev.124.4.925] [Citation(s) in RCA: 189] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Caenorhabditis elegans germ-line proliferation is controlled by an inductive interaction between the somatic distal tip cell and the germ line. GLP-1, a member of the Notch family of transmembrane receptors, is required continuously in the germ line to transduce the proliferative signal. In the absence of GLP-1, all proliferative germ cells exit the mitotic cell cycle and enter meiotic prophase. We have characterized an activating mutation in glp-1, oz112gf, that has the opposite phenotype. Homozygous glp-1(oz112gf) hermaphrodites and males have a completely tumorous germ line in which germ cells never leave the mitotic cycle. In glp-1(oz112gf) heterozygotes, germ-line polarity is established correctly, but as adults age, the distal proliferative population expands leading to a late-onset tumorous phenotype. The mutant receptor is constitutively active, promoting proliferation in the absence of ligand. The normal distal-proximal spatial restriction of GLP-1 expression is lost in tumorous and late-onset tumorous animals; ectopically proliferating germ cells contain membrane-associated GLP-1. The correlation between proliferation and expression, both in wild-type where glp-1 signalling is limited by localized ligand and in glp-1(oz112gf) where signalling is ligand-independent, suggests that glp-1 signalling positively regulates GLP-1 expression. In addition to germ-line defects, glp-1(oz112gf) causes inappropriate vulval cell fate specification. A missense mutation in a conserved extracellular residue, Ser642, adjacent to the transmembrane domain, is sufficient to confer the glp-1(oz112gf) mutant phenotypes. Two mammalian Notch family members, TAN-1 and int-3, are proto-oncogenes. Thus, activating mutations in both invertebrate and vertebrate Notch family members can lead to tumor formation.
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Affiliation(s)
- L W Berry
- Department of Genetics, Washington University School of Medicine, St Louis, MO 63110, USA
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15
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McCarter J, Bartlett B, Dang T, Schedl T. Soma-germ cell interactions in Caenorhabditis elegans: multiple events of hermaphrodite germline development require the somatic sheath and spermathecal lineages. Dev Biol 1997; 181:121-43. [PMID: 9013925 DOI: 10.1006/dbio.1996.8429] [Citation(s) in RCA: 209] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Germ cells complete multiple events to form functional oocytes and sperm. In the Caenorhabditis elegans hermaphrodite, germ cells develop in proximity to the somatic gonad sheath and spermathecal cells. We present evidence from cellular laser ablation studies indicating that cells of the somatic sheath and spermathecal lineages play critical roles in four events of hermaphrodite germline development. (1) Cells of the sheath and spermathecal lineage support germline proliferation; ablation of sheath/spermathecal precursor cells reduces mitotic proliferation. (2) These cells also play a role in the exit of germ cells from the pachytene stage of meiotic prophase and/or gamete differentiation; ablation can result in undifferentiated germ cells arrested in pachytene. (3) Proximal sheath and distal spermatheca cells are required for ovulation of the oocyte. During wild-type ovulation, the mature oocyte is expelled from the gonad arm by contraction of the proximal myoepithelial sheath and dilation of the distal spermatheca. Ablation of these cells traps mature oocytes in the gonad arm where they endomitotically replicate their DNA (the Emo phenotype). (4) Cells of the sheath and spermathecal lineage also appear to promote the male germ cell fate since ablation of one sheath/spermathecal precursor cell can feminize the hermaphrodite germ line. These somatic ablation-induced germline phenotypes demonstrate that the somatic gonad is required for multiple events in C. elegans germline development. Further, these results suggest that soma to germline cell-cell interactions in C. elegans are physiological in character (i.e., contraction during ovulation) as well as regulatory.
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Affiliation(s)
- J McCarter
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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16
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Jones AR, Francis R, Schedl T. GLD-1, a cytoplasmic protein essential for oocyte differentiation, shows stage- and sex-specific expression during Caenorhabditis elegans germline development. Dev Biol 1996; 180:165-83. [PMID: 8948583 DOI: 10.1006/dbio.1996.0293] [Citation(s) in RCA: 234] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
GLD-1, a putative RNA binding protein, is essential for oocyte development in Caenorhabditis elegans. A gld-1 null mutation abolishes hermaphrodite oogenesis and confers a tumorous germline phenotype in which presumptive female germ cells exit the meiotic pathway and return to the mitotic cell cycle. Here we demonstrate that gld-1(null) germ lines express female-specific, but not male-specific, molecular markers, indicating that gld-1 acts downstream of sexual fate specification to regulate oocyte differentiation. Immunolocalization studies identify GLD-1 as a cytoplasmic germline protein that displays differential accumulation during germline development. First, germ cells that are in the mitotic cell cycle contain low levels of GLD-1 that likely reflect a nonessential gld-1 function (negative regulation of proliferation in the mitotic germ line) revealed in previous genetic studies. Second, entry of presumptive oocytes into the meiotic pathway is accompanied by a strong increase in GLD-1 expression/accumulation. GLD-1 levels are high through the pachytene stage but fall to background as germ cells exit pachytene and complete oogenesis. The meiotic prophase accumulation pattern is consistent with GLD-1's essential role in oocyte differentiation, which may be to repress the translation of a subset of maternal RNAs synthesized during early oogenesis until late oogenesis when GLD-1 is absent.
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Affiliation(s)
- A R Jones
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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17
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Abstract
BACKGROUND The nematode Caenorhabditis elegans offers many advantages as a model organism for studying volatile anesthetic actions. It has a simple, well-understood nervous system; it allows the researcher to do forward genetics; and its genome will soon be completely sequenced. C. elegans is immobilized by volatile anesthetics only at high concentrations and with an unusually slow time course. Here other behavioral dysfunctions are considered as anesthetic endpoints in C. elegans. METHODS The potency of halothane for disrupting eight different behaviors was determined by logistic regression of concentration and response data. Other volatile anesthetics were also tested for some behaviors. Established protocols were used for behavioral endpoints that, except for pharyngeal pumping, were set as complete disruption of the behavior. Time courses were measured for rapid behaviors. Recovery from exposure to 1 or 4 vol% halothane was determined for mating, chemotaxis, and gross movement. All experiments were performed at 20 to 22 degrees C. RESULTS The median effective concentration values for halothane inhibition of mating (0.30 vol%-0.21 mM), chemotaxis (0.34 vol%-0.24 mM), and coordinated movement (0.32 vol% - 0.23 mM) were similar to the human minimum alveolar concentration (MAC; 0.21 mM). In contrast, halothane produced immobility with a median effective concentration of 3.65 vol% (2.6 mM). Other behaviors had intermediate sensitivities. Halothane's effects reached steady-state in 10 min for all behaviors tested except immobility, which required 2 h. Recovery was complete after exposure to 1 vol% halothane but was significantly reduced after exposure to immobilizing concentrations. CONCLUSIONS Volatile anesthetics selectively disrupt C. elegans behavior. The potency, time course, and recovery characteristics of halothane's effects on three behaviors are similar to its anesthetic properties in vertebrates. The affected nervous system molecules may express structural motifs similar to those on vertebrate anesthetic targets.
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Affiliation(s)
- C M Crowder
- Department of Anesthesiology, Washington University School of Medicine, Saint Louis, Missouri, USA.
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18
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Kloek AP, McCarter JP, Setterquist RA, Schedl T, Goldberg DE. Caenorhabditis globin genes: rapid intronic divergence contrasts with conservation of silent exonic sites. J Mol Evol 1996; 43:101-8. [PMID: 8660434 DOI: 10.1007/bf02337354] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Globin genes from the Caenorhabditis species briggsae and remanei were identified and compared with a previously described C. elegans globin gene. The encoded globins share between 86% and 93% amino acid identity, with most of the changes in or just before the putative B helix. C. remanei was found to have two globin alleles, Crg1-1 and Crg1-2. The coding sequence for each is interrupted by a single intron in the same position. The exons of the two genes are only 1% divergent at the nucleotide level and encode identical polypeptides. In contrast, intron sequence divergence is 16% and numerous insertions and deletions have significantly altered the size and content of both introns. Genetic crosses show that Crg1-1 and Crg1-2 segregate as alleles. Homozygous lines for each allele were constructed and northern analysis confirmed the expression of both alleles. These data reveal an unusual situation wherein two alleles encoding identical proteins have diverged much more rapidly in their introns than the silent sites of their coding sequences, suggesting multiple gene conversion events.
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Affiliation(s)
- A P Kloek
- Department of Molecular Microbiology, Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, MO 63110, USA
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19
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Abstract
emo-1(oz1) is a member of a class of hermaphrodite sterile mutations in Caenorhabditis elegans that produce endomitotic oocytes in the gonad arm. Oocytes in emo-1(oz1) mutants exhibit multiple defects during oogenesis. After meiotic maturation, ovulation fails, trapping oocytes in the gonad arm where they become endomitotic. emo-1 encodes a homologue of the Sec61p gamma subunit, a protein necessary for translocation of secretory and transmembrane proteins into the endoplasmic reticulum of yeast and mammalian cells. A putative emo-1 null mutation, oz151, displays embryonic lethality. The oz1 sterile mutation is a transposable element insertion into the emo-1 3' untranslated region that almost completely eliminates germline mRNA accumulation. Genetic mosaic analysis using the oz1 allele indicates that emo-1(+) expression in germ cells is required for fertility. The J67 monoclonal antibody, which recognizes an oocyte surface antigen (Strome, S. 1986. In Gametogenesis and the Early Embryo. J.G. Gall, editor. Alan R. Liss, Inc., New York. 77-95.), does not stain oz1 oocytes, a finding consistent with defective protein transport in the mutant. We propose that the emo-1 gene product acts in the transport of secreted and transmembrane proteins in C. elegans oocytes, and is necessary for both oogenesis and the coupling of ovulation with meiotic maturation.
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Affiliation(s)
- K Iwasaki
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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20
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Jones AR, Schedl T. Mutations in gld-1, a female germ cell-specific tumor suppressor gene in Caenorhabditis elegans, affect a conserved domain also found in Src-associated protein Sam68. Genes Dev 1995; 9:1491-504. [PMID: 7601353 DOI: 10.1101/gad.9.12.1491] [Citation(s) in RCA: 217] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The gld-1 gene of Caenorhabditis elegans is a germ-line-specific tumor suppressor gene that is essential for oogenesis. We have cloned the gld-1 gene and find that it encodes two proteins that differ by 3 amino acids. The predicted proteins contain a approximately 170-amino-acid region that we term the GSG domain (GRP33/Sam68/GLD-1), on the basis of significant similarity between GLD-1, GRP33 from shrimp, and the Src-associated protein Sam68 from mouse (also described as GAPap62 from humans). A conserved structural motif called the KH domain is found within the larger GSG domain, suggesting a biochemical function for GLD-1 protein in binding RNA. The importance of the GSG domain to the function of gld-1 in vivo is revealed by mutations that affect 5 different conserved GSG domain residues. These include missense mutations in an absolutely conserved residue of the KH domain that eliminate the tumor suppressor function of gld-1.
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Affiliation(s)
- A R Jones
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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21
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Francis R, Maine E, Schedl T. Analysis of the multiple roles of gld-1 in germline development: interactions with the sex determination cascade and the glp-1 signaling pathway. Genetics 1995; 139:607-30. [PMID: 7713420 PMCID: PMC1206369 DOI: 10.1093/genetics/139.2.607] [Citation(s) in RCA: 157] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The Caenorhabditis elegans gene gld-1 is essential for oocyte development; in gld-1 (null) hermaphrodites, a tumor forms where oogenesis would normally occur. We use genetic epistasis analysis to demonstrate that tumor formation is dependent on the sexual fate of the germline. When the germline sex determination pathway is set in the female mode (terminal fem/fog genes inactive), gld-1 (null) germ cells exit meiotic prophase and proliferate to form a tumor, but when the pathway is set in the male mode, they develop into sperm. We conclude that the gld-1 (null) phenotype is cell-type specific and that gld-1(+) acts at the end of the cascade to direct oogenesis. We also use cell ablation and epistasis analysis to examine the dependence of tumor formation on the glp-1 signaling pathway. Although glp-1 activity promotes tumor growth, it is not essential for tumor formation by gld-1 (null) germ cells. These data also reveal that gld-1(+) plays a nonessential (and sex nonspecific) role in regulating germ cell proliferation before their entry into meiosis. Thus gld-1(+) may negatively regulate proliferation at two distinct points in germ cell development: before entry into meiotic prophase in both sexes (nonessential premeiotic gld-1 function) and during meiotic prophase when the sex determination pathway is set in the female mode (essential meiotic gld-1 function).
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Affiliation(s)
- R Francis
- Department of Genetics, Washington University School of Medicine, St. Louis Missouri 63110, USA
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22
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Abstract
We have characterized 31 mutations in the gld-1 (defective in germline development) gene of Caenorhabditis elegans. In gld-1 (null) hermaphrodites, oogenesis is abolished and a germline tumor forms where oocyte development would normally occur. By contrast, gld-1 (null) males are unaffected. The hermaphrodite germline tumor appears to derive from germ cells that enter the meiotic pathway normally but then exit pachytene and return to the mitotic cycle. Certain gld-1 partial loss-of-function mutations also abolish oogenesis, but germ cells arrest in pachytene rather than returning to mitosis. Our results indicate that gld-1 is a tumor suppressor gene required for oocyte development. The tumorous phenotype suggests that gld-1(+) may function to negatively regulate proliferation during meiotic prophase and/or act to direct progression through meiotic prophase. We also show that gld-1(+) has an additional nonessential role in germline sex determination: promotion of hermaphrodite spermatogenesis. This function of gld-1 is inferred from a haplo-insufficient phenotype and from the properties of gain-of-function gld-1 mutations that cause alterations in the sexual identity of germ cells.
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Affiliation(s)
- R Francis
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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23
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Graham PL, Schedl T, Kimble J. More mog genes that influence the switch from spermatogenesis to oogenesis in the hermaphrodite germ line of Caenorhabditis elegans. Dev Genet 1993; 14:471-84. [PMID: 8111975 DOI: 10.1002/dvg.1020140608] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The Caenorhabditis elegans XX animal possesses a hermaphrodite germ line, producing first sperm, then oocytes. In this paper, we report the genetic identification of five genes, mog-2, mog-3, mog-4, mog-5, and mog-6, that influence the hermaphrodite switch from spermatogenesis to oogenesis. In mog-2-mog-6 mutants, spermatogenesis continues past the time at which hermaphrodites normally switch into oogenesis and no oocytes are observed. Therefore, in these mutants, germ cells are transformed from a female fate (oocyte) to a male fate (sperm). The fem-3 gene is one of five genes that acts at the end of the germline sex determination pathway to direct spermatogenesis. Analyses of mog;fem-3 double mutants suggest that the mog-2-mog-6 genes act before fem-3; thus these genes may be in a position to negatively regulate fem-3 or one of the other terminal regulators of germline sex determination. Double mutants of fem-3 and any one of the mog mutations make oocytes. Using these double mutants, we show that oocytes from any mog;fem-3 double mutant are defective in their ability to support embryogenesis. This maternal effect lethality indicates that each of the mog genes is required for embryogenesis. The two defects in mog-2-mog-6 mutants are similar to those of mog-1: all six mog genes eliminate the sperm/oocyte switch in hermaphrodites and cause maternal effect lethality. We propose that the mog-2-mog-6 mutations identify genes that act with mog-1 to effect the sperm/oocyte switch. We further speculate that the mog-1-mog-6 mutations all interfere with translational controls of fem-3 and other maternal mRNAs.
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Affiliation(s)
- P L Graham
- Department of CMS Biology, Northwestern University Medical School, Chicago, Illinois
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24
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Abstract
This review addresses the role of cell-cell interactions in the development of the Caenorhabditis elegans germ line: specifically, the relative contributions of germ-line-soma interactions versus autonomous processes are considered. Current knowledge of the interacting cell types and the genes essential for various aspects of germ-line development is discussed.
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Affiliation(s)
- T Schedl
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri
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25
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Abstract
In each gonadal arm of wild-type C. elegans hermaphrodites, the somatic distal tip cell (DTC) maintains distal germline nuclei in mitosis, while proximal nuclei enter meiosis. We have identified two conditions under which a proximal somatic cell, the anchor cell (AC), inappropriately maintains proximal germline nuclei in mitosis: when defined somatic gonadal cells have been ablated in wild type, and in lin-12 null mutants. Laser ablations and mosaic analysis indicate that somatic gonadal cells neighboring the AC normally require lin-12 activity to prevent the inappropriate AC-germline interaction. The AC-germline interaction, like the DTC-germline interaction, requires glp-1 activity. In one model, we propose that the AC sends an intercellular signal intended to interact with the lin-12 product in somatic gonadal cells; when lin-12 activity is absent, the signal interacts instead with the related glp-1 product in germline. Our data illustrate the importance of mechanisms that prevent inappropriate interactions during development.
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Affiliation(s)
- G Seydoux
- Department of Biology, Princeton University, New Jersey 08544
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26
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Abstract
In wild-type Caenorhabditis elegans there are two sexes, self-fertilizing hermaphrodites (XX) and males (XO). To investigate the role of tra-1 in controlling sex determination in germline tissue, we have examined germline phenotypes of nine tra-1 loss-of-function (lf) mutations. Previous work has shown that tra-1 is needed for female somatic development as the nongonadal soma of tra-1(lf) XX mutants is masculinized. In contrast, the germline of tra-1(lf) XX and XO animals is often feminized; a brief period of spermatogenesis is followed by oogenesis, rather than the continuous spermatogenesis observed in wild-type males. In addition, abnormal gonadal (germ line and somatic gonad) phenotypes are observed which may reflect defects in development or function of somatic gonad regulatory cells. Analysis of germline feminization and abnormal gonadal phenotypes of the various mutations alone or in trans to a deficiency reveals that they cannot be ordered in an allelic series and they do not converge to a single phenotypic endpoint. These observations lead to the suggestion that tra-1 may produce multiple products and/or is autoregulated. One interpretation of the germline feminization is that tra-1(+) is necessary for continued specification of spermatogenesis in males. We also report the isolation and characterization of tra-1 gain-of-function (gf) mutations with novel phenotypes. These include temperature sensitive, recessive germline feminization, and partial somatic loss-of-function phenotypes.
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Affiliation(s)
- T Schedl
- Laboratory of Molecular Biology, Graduate School, University of Wisconsin, Madison 53706
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27
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Abstract
This paper describes the isolation and characterization of 16 mutations in the germ-line sex determination gene fog-2 (fog for feminization of the germ line). In the nematode Caenorhabditis elegans there are normally two sexes, self-fertilizing hermaphrodites (XX) and males (XO). Wild-type XX animals are hermaphrodite in the germ line (spermatogenesis followed by oogenesis), and female in the soma. fog-2 loss-of-function mutations transform XX animals into females while XO animals are unaffected. Thus, wild-type fog-2 is necessary for spermatogenesis in hermaphrodites but not males. The fem genes and fog-1 are each essential for specification of spermatogenesis in both XX and XO animals. fog-2 acts as a positive regulator of the fem genes and fog-1. The tra-2 and tra-3 genes act as negative regulators of the fem genes and fog-1 to allow oogenesis. Two models are discussed for how fog-2 might positively regulate the fem genes and fog-1 to permit spermatogenesis; fog-2 may act as a negative regulator of tra-2 and tra-3, or fog-2 may act positively on the fem genes and fog-1 rendering them insensitive to the negative action of tra-2 and tra-3.
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Affiliation(s)
- T Schedl
- Laboratory of Cell and Molecular Biology, Graduate School, Univesity of Wisconsin, Madison 53706
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Krämmer G, Singhofer-Wowra M, Seedorf K, Little M, Schedl T. A plasmodial alpha-tubulin cDNA from Physarum polycephalum. Nucleotide sequence and comparative analysis. J Mol Biol 1985; 183:633-8. [PMID: 4020874 DOI: 10.1016/0022-2836(85)90176-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
As the first step towards correlating structure and function of tubulin in the slime mold Physarum polycephalum we have elucidated the nucleotide sequence of a cDNA that appears to code for all but the last 25 to 30 C-terminal amino acids of a plasmodial alpha-tubulin. Differences in amino acid sequence from those of other alpha-tubulins are distributed fairly evenly throughout the sequence, although a relatively extensive conserved region is found in position 396 to 426 near the C terminus. A small region in position 298 to 307 contains a cluster of amino acid residues unique to Physarum alpha-tubulin. The sequence is 70% homologous to two yeast alpha-tubulins and about 83% homologous to five animal alpha-tubulins. A comparison of the homologies of all the known alpha-tubulins indicates that a large decrease in the accepted point mutation rate has occurred during the evolution of the metazoa, suggesting a major functional specialization of microtubules.
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29
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Abstract
The organization of the alpha- and beta-tubulin gene families in Physarum was investigated by Mendelian analysis. Restriction endonuclease-generated DNA fragments homologous to alpha- and beta-tubulin show length polymorphisms that can be used as markers for genetic mapping. Analysis of meiotic assortment among progeny of heterozygotes allowed alpha- and beta-tubulin sequence loci to be defined. There are four unlinked alpha-tubulin sequence loci (altA, altB, altC and altD) and at least three unlinked beta-tubulin sequence loci (betA, betB and betC). The alpha-tubulin loci are not linked to the beta-tubulin loci. --Segregation of tubulin sequence loci with respect to ben mutations that confer resistance to antitubulin benzimidazole drugs was used to investigate whether any members of the alpha- or beta-tubulin gene families are allelic to ben loci. The beta-tubulin sequence locus betB is allelic to the resistance locus benD, the betA locus is probably allelic to benA and the alpha-tubulin sequence locus altC may be allelic to benC. The molecular implications of benzimidazole resistance phenotypes when only one of the expressed beta-tubulin gene family members mutates to drug resistance are discussed in relation to tubulin function.
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Burland TG, Schedl T, Gull K, Dove WF. Genetic analysis of resistance to benzimidazoles in Physarum: differential expression of beta-tubulin genes. Genetics 1984; 108:123-41. [PMID: 6479584 PMCID: PMC1202390 DOI: 10.1093/genetics/108.1.123] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Physarum displays two vegetative cell types, uninucleate myxamoebae and multinucleate plasmodia. Mutant myxamoebae of Physarum resistant to the antitubulin drug methylbenzimidazole-2-yl-carbamate (MBC) were isolated. All mutants tested were cross-resistant to other benzimidazoles but not to cycloheximide or emetine. Genetic analysis showed that mutation to MBC resistance can occur at any one of four unlinked loci, benA, benB, benC or benD. MBC resistance of benB and benD mutants was expressed in plasmodia, but benA and benC mutant plasmodia were MBC sensitive, suggesting that benA and benC encode myxamoeba-specific products. Myxamoebae carrying the recessive benD210 mutation express a beta-tubulin with novel electrophoretic mobility, in addition to a beta-tubulin with wild-type mobility. This and other evidence indicates that benD is a structural gene for beta-tubulin, and that at least two beta-tubulin genes are expressed in myxamoebae. Comparisons of the beta-tubulins of wild-type and benD210 strains by gel electrophoresis revealed that, of the three (or more) beta-tubulin genes expressed in Physarum, one, benD, is expressed in both myxamoebae and plasmodia, one is expressed specifically in myxamoebae and one is expressed specifically in plasmodia. However, mutation in only one gene, benD, is sufficient to confer MBC resistance on both myxamoebae and plasmodia.
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Schedl T, Burland TG, Gull K, Dove WF. Cell cycle regulation of tubulin RNA level, tubulin protein synthesis, and assembly of microtubules in Physarum. J Cell Biol 1984; 99:155-65. [PMID: 6203916 PMCID: PMC2275639 DOI: 10.1083/jcb.99.1.155] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The temporal relationship between tubulin expression and the assembly of the mitotic spindle microtubules has been investigated during the naturally synchronous cell cycle of the Physarum plasmodium. The cell cycle behavior of the tubulin isoforms was examined by two-dimensional gel electrophoresis of proteins labeled in vivo and by translation of RNA in vitro. alpha 1-, alpha 2-, beta 1-, and beta 2-tubulin synthesis increases coordinately until metaphase, and then falls, with beta 2 falling more rapidly than beta 1. Nucleic acid hybridization demonstrated that alpha- and beta-tubulin RNAs accumulate coordinately during G2, peaking at metaphase. Quantitative analysis demonstrated that alpha-tubulin RNA increases with apparent exponential kinetics, peaking with an increase over the basal level of greater than 40-fold. After metaphase, tubulin RNA levels fall exponentially, with a short half-life (19 min). Electron microscopic analysis of the plasmodium showed that the accumulation of tubulin RNA begins long before the polymerization of mitotic spindle microtubules. By contrast, the decay of tubulin RNA after metaphase coincides with the depolymerization of the spindle microtubules.
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32
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Abstract
Three alpha-tubulins and two beta-tubulins have been resolved by two-dimensional gel electrophoresis of whole cell lysates of Physarum myxamoebae or plasmodia. Criteria used to identify the tubulins included migration on two-dimensional gels with myxamoebal tubulins purified by self-assembly into microtubules in vitro, peptide mapping with Staphylococcus V8 protease and with chymotrypsin, immunoprecipitation with a monoclonal antibody specific for beta-tubulin, and, finally, hybrid selection of specific mRNA by cloned tubulin DNA sequences, followed by translation in vitro. Differential expression of the Physarum tubulins was observed. The alpha 1- and beta 1-tubulins were detected in both myxamoebae and plasmodia; alpha 2 and beta 2 were detected only in plasmodia, alpha 3 was detected only in the myxamoebal phase, and may be specific to the flagellate. Observation of more tubulin species in plasmodia than in myxamoebae was remarkable; the only microtubules detected in plasmodia are those of the mitotoic spindle, whereas myxamoebae display cytoplasmic, centriolar, flagellar, and mitotic-spindle microtubules. In vitro translation of myxamoebal and plasmodial RNAs indicated that there are distinct mRNAs, and therefore probably separate genes, for the alpha 1-, alpha 2-, beta 1-, and beta 2-tubulins. Thus, the different patterns of tubulin expression in myxamoebae and plasmodia reflect differential expression of tubulin genes.
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Kinniburgh AJ, Maquat LE, Schedl T, Rachmilewitz E, Ross J. mRNA-deficient beta o-thalassemia results from a single nucleotide deletion. Nucleic Acids Res 1982; 10:5421-7. [PMID: 6292840 PMCID: PMC320886 DOI: 10.1093/nar/10.18.5421] [Citation(s) in RCA: 90] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The beta-globin gene of a patient with mRNA-deficient beta o-thalassemia has been sequenced. We find a single nucleotide deletion in amino acid codon 44 that produces a UGA terminator at codon 60. We have previously shown that the beta-globin mRNA of this patient is correctly spliced and polyadenylated, but rapidly turns over with a half-life of less than 30 min. We suggest that the rapid mRNA turnover is influenced by the deletion of this single nucleotide as well as by the nonsense codon.
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