1
|
Prakash R, Rawal Y, Sullivan MR, Grundy MK, Bret H, Mihalevic MJ, Rein HL, Baird JM, Darrah K, Zhang F, Wang R, Traina TA, Radke MR, Kaufmann SH, Swisher EM, Guérois R, Modesti M, Sung P, Jasin M, Bernstein KA. Homologous recombination-deficient mutation cluster in tumor suppressor RAD51C identified by comprehensive analysis of cancer variants. Proc Natl Acad Sci U S A 2022; 119:e2202727119. [PMID: 36099300 PMCID: PMC9499524 DOI: 10.1073/pnas.2202727119] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [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: 02/17/2022] [Accepted: 08/09/2022] [Indexed: 01/05/2023] Open
Abstract
Mutations in homologous recombination (HR) genes, including BRCA1, BRCA2, and the RAD51 paralog RAD51C, predispose to tumorigenesis and sensitize cancers to DNA-damaging agents and poly(ADP ribose) polymerase inhibitors. However, ∼800 missense variants of unknown significance have been identified for RAD51C alone, impairing cancer risk assessment and therapeutic strategies. Here, we interrogated >50 RAD51C missense variants, finding that mutations in residues conserved with RAD51 strongly predicted HR deficiency and disrupted interactions with other RAD51 paralogs. A cluster of mutations was identified in and around the Walker A box that led to impairments in HR, interactions with three other RAD51 paralogs, binding to single-stranded DNA, and ATP hydrolysis. We generated structural models of the two RAD51 paralog complexes containing RAD51C, RAD51B-RAD51C-RAD51D-XRCC2 and RAD51C-XRCC3. Together with our functional and biochemical analyses, the structural models predict ATP binding at the interface of RAD51C interactions with other RAD51 paralogs, similar to interactions between monomers in RAD51 filaments, and explain the failure of RAD51C variants in binding multiple paralogs. Ovarian cancer patients with variants in this cluster showed exceptionally long survival, which may be relevant to the reversion potential of the variants. This comprehensive analysis provides a framework for RAD51C variant classification. Importantly, it also provides insight into the functioning of the RAD51 paralog complexes.
Collapse
Affiliation(s)
- Rohit Prakash
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Yashpal Rawal
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229
| | - Meghan R. Sullivan
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - McKenzie K. Grundy
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - Hélène Bret
- Institute for Integrative Biology of the Cell, Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, 91198 France
| | - Michael J. Mihalevic
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - Hayley L. Rein
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - Jared M. Baird
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - Kristie Darrah
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - Fang Zhang
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853
| | - Raymond Wang
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Tiffany A. Traina
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Marc R. Radke
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle, WA 98195
| | - Scott H. Kaufmann
- Departments of Oncology and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905
| | - Elizabeth M. Swisher
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle, WA 98195
| | - Raphaël Guérois
- Institute for Integrative Biology of the Cell, Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, 91198 France
| | - Mauro Modesti
- Cancer Research Center of Marseille, CNRS, INSERM, Institut Paoli-Calmettes, Aix-Marseille Université, Marseille, 13273 France
| | - Patrick Sung
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Kara A. Bernstein
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| |
Collapse
|
2
|
Prakash R, Sandoval T, Morati F, Zagelbaum JA, Lim PX, White T, Taylor B, Wang R, Desclos ECB, Sullivan MR, Rein HL, Bernstein KA, Krawczyk PM, Gautier J, Modesti M, Vanoli F, Jasin M. Distinct pathways of homologous recombination controlled by the SWS1-SWSAP1-SPIDR complex. Nat Commun 2021; 12:4255. [PMID: 34253720 PMCID: PMC8275761 DOI: 10.1038/s41467-021-24205-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 06/04/2021] [Indexed: 02/06/2023] Open
Abstract
Homology-directed repair (HDR), a critical DNA repair pathway in mammalian cells, is complex, leading to multiple outcomes with different impacts on genomic integrity. However, the factors that control these different outcomes are often not well understood. Here we show that SWS1-SWSAP1-SPIDR controls distinct types of HDR. Despite their requirement for stable assembly of RAD51 recombinase at DNA damage sites, these proteins are not essential for intra-chromosomal HDR, providing insight into why patients and mice with mutations are viable. However, SWS1-SWSAP1-SPIDR is critical for inter-homolog HDR, the first mitotic factor identified specifically for this function. Furthermore, SWS1-SWSAP1-SPIDR drives the high level of sister-chromatid exchange, promotes long-range loss of heterozygosity often involved with cancer initiation, and impels the poor growth of BLM helicase-deficient cells. The relevance of these genetic interactions is evident as SWSAP1 loss prolongs Blm-mutant embryo survival, suggesting a possible druggable target for the treatment of Bloom syndrome.
Collapse
Affiliation(s)
- Rohit Prakash
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
| | - Thomas Sandoval
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Florian Morati
- Cancer Research Center of Marseille, CNRS, Inserm, Institut Paoli-Calmettes, Aix-Marseille Université, Marseille, France
| | - Jennifer A Zagelbaum
- Department of Genetics and Development and Institute for Cancer Genetics, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Pei-Xin Lim
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Travis White
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Brett Taylor
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Raymond Wang
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Emilie C B Desclos
- Department of Medical Biology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Meghan R Sullivan
- Department of Microbiology and Molecular Genetics, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Hayley L Rein
- Department of Microbiology and Molecular Genetics, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Kara A Bernstein
- Department of Microbiology and Molecular Genetics, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Przemek M Krawczyk
- Department of Medical Biology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Jean Gautier
- Department of Genetics and Development and Institute for Cancer Genetics, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Mauro Modesti
- Cancer Research Center of Marseille, CNRS, Inserm, Institut Paoli-Calmettes, Aix-Marseille Université, Marseille, France
| | - Fabio Vanoli
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
| |
Collapse
|
3
|
Sullivan MR, Prakash R, Rawal Y, Wang W, Sung P, Radke MR, Kaufmann SH, Swisher EM, Bernstein KA, Jasin M. Long-term survival of an ovarian cancer patient harboring a RAD51C missense mutation. Cold Spring Harb Mol Case Stud 2021; 7:mcs.a006083. [PMID: 33832919 PMCID: PMC8040731 DOI: 10.1101/mcs.a006083] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 01/28/2021] [Indexed: 11/30/2022] Open
Abstract
Mutations in homologous recombination (HR) genes predispose to cancer but also sensitize to chemotherapeutics. Although therapy can initially be effective, cancers frequently cease responding, leading to recurrence and poor prognosis. Here we identify a germline mutation in RAD51C, a critical HR factor and known tumor suppressor, in an ovarian cancer patient with exceptionally long, progression-free survival. The RAD51C–T132P mutation is in a highly conserved residue within the nucleotide-binding site and interferes with single-strand DNA binding of the RAD51 paralog complex RAD51B–RAD51C–RAD51D–XRCC2 and association with another RAD51 paralog XRCC3. These biochemical defects lead to highly defective HR and drug sensitivity in tumor cells, ascribing RAD51C–T132P as a deleterious mutation that was likely causal for tumor formation. Conversely, its position within a critical site suggests that it is refractory to secondary mutations that would restore RAD51C gene function and lead to therapy resistance. A need for a greater understanding of the relationship between mutation position and reversion potential of HR genes is underscored, as it may help predict the effectiveness of therapies in patients with HR-deficient cancers.
Collapse
Affiliation(s)
- Meghan R Sullivan
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA
| | - Rohit Prakash
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10021, USA
| | - Yashpal Rawal
- Department of Biochemistry and Structural Biology, UT Health Science Center at San Antonio, San Antonio, Texas 78229, USA
| | - Weibin Wang
- Department of Radiation Medicine, Peking University Health Science Center, Beijing, 100191, China
| | - Patrick Sung
- Department of Biochemistry and Structural Biology, UT Health Science Center at San Antonio, San Antonio, Texas 78229, USA
| | - Marc R Radke
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle, Washington 98195, USA
| | - Scott H Kaufmann
- Departments of Oncology and Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Elizabeth M Swisher
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle, Washington 98195, USA
| | - Kara A Bernstein
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10021, USA
| |
Collapse
|
4
|
Sullivan MR, Prakash R, Mihalevic MJ, Baird JM, Jasin M, Bernstein KA. Abstract A08: A novel system determines the functional significance of ovarian tumor mutations in the homologous recombination gene RAD51C. Clin Cancer Res 2018. [DOI: 10.1158/1557-3265.ovca17-a08] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Homologous recombination (HR) deficiency is associated with hereditary ovarian carcinomas. HR deficiency can occur through somatic and germline mutations in BRCA1, BRCA2, and other associated genes such as RAD51C. Understanding the impact of HR gene mutations on DNA double-strand break (DSB) repair is critical for developing targeted therapeutic strategies for these patients. Although BRCA1 and BRCA2 deficiency has been well characterized, limited functional analysis has occurred in patients harboring mutations in RAD51C. RAD51C mutations are found in familial breast and ovarian cancers and in Fanconi anemia-like syndrome, FANCO. To determine which RAD51C-tumor associated mutations disrupt HR, we utilized a novel RAD51C conditional knockout breast epithelial cell line (MCF10A) generated by Dr. Maria Jasin. In collaboration with the Jasin laboratory, we complemented these cells with RAD51C and RAD51C cancer-associated mutants. Using yeast-two-hybrid and co-immunoprecipitation strategies, we identified RAD51C mutations that disrupt RAD51C protein-protein interactions. For example, we identified RAD51C mutations that impair RAD51C interaction with either its binding partner RAD51B, RAD51D, or XRCC3. We next measured RAD51C mutant cells for viability and HR proficiency at an I-SceI-induced DSB using a DR-GFP reporter assay. We identified RAD51C mutations that impact HR repair, suggesting that patients harboring these mutations would be good candidates for PARPi. Our goal is to identify specific RAD51C mutations that disrupt HR to predict which RAD51C-deficient tumors will respond to therapy.
Citation Format: Meghan R. Sullivan, Rohit Prakash, Michael J. Mihalevic, Jared M. Baird, Maria Jasin, Kara A. Bernstein. A novel system determines the functional significance of ovarian tumor mutations in the homologous recombination gene RAD51C. [abstract]. In: Proceedings of the AACR Conference: Addressing Critical Questions in Ovarian Cancer Research and Treatment; Oct 1-4, 2017; Pittsburgh, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(15_Suppl):Abstract nr A08.
Collapse
Affiliation(s)
- Meghan R. Sullivan
- 1University of Pittsburgh Medical Center Hillman Cancer Center, Pittsburgh, PA,
| | - Rohit Prakash
- 2Memorial Sloan Kettering Cancer Center, New York, NY
| | | | - Jared M. Baird
- 1University of Pittsburgh Medical Center Hillman Cancer Center, Pittsburgh, PA,
| | - Maria Jasin
- 2Memorial Sloan Kettering Cancer Center, New York, NY
| | - Kara A. Bernstein
- 1University of Pittsburgh Medical Center Hillman Cancer Center, Pittsburgh, PA,
| |
Collapse
|
5
|
Kondrashova O, Nguyen M, Shield-Artin K, Tinker AV, Teng NNH, Harrell MI, Kuiper MJ, Ho GY, Barker H, Jasin M, Prakash R, Kass EM, Sullivan MR, Brunette GJ, Bernstein KA, Coleman RL, Floquet A, Friedlander M, Kichenadasse G, O'Malley DM, Oza A, Sun J, Robillard L, Maloney L, Bowtell D, Giordano H, Wakefield MJ, Kaufmann SH, Simmons AD, Harding TC, Raponi M, McNeish IA, Swisher EM, Lin KK, Scott CL. Secondary Somatic Mutations Restoring RAD51C and RAD51D Associated with Acquired Resistance to the PARP Inhibitor Rucaparib in High-Grade Ovarian Carcinoma. Cancer Discov 2017; 7:984-998. [PMID: 28588062 PMCID: PMC5612362 DOI: 10.1158/2159-8290.cd-17-0419] [Citation(s) in RCA: 278] [Impact Index Per Article: 39.7] [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] [Received: 04/21/2017] [Revised: 06/01/2017] [Accepted: 06/02/2017] [Indexed: 11/16/2022]
Abstract
High-grade epithelial ovarian carcinomas containing mutated BRCA1 or BRCA2 (BRCA1/2) homologous recombination (HR) genes are sensitive to platinum-based chemotherapy and PARP inhibitors (PARPi), while restoration of HR function due to secondary mutations in BRCA1/2 has been recognized as an important resistance mechanism. We sequenced core HR pathway genes in 12 pairs of pretreatment and postprogression tumor biopsy samples collected from patients in ARIEL2 Part 1, a phase II study of the PARPi rucaparib as treatment for platinum-sensitive, relapsed ovarian carcinoma. In 6 of 12 pretreatment biopsies, a truncation mutation in BRCA1, RAD51C, or RAD51D was identified. In five of six paired postprogression biopsies, one or more secondary mutations restored the open reading frame. Four distinct secondary mutations and spatial heterogeneity were observed for RAD51CIn vitro complementation assays and a patient-derived xenograft, as well as predictive molecular modeling, confirmed that resistance to rucaparib was associated with secondary mutations.Significance: Analyses of primary and secondary mutations in RAD51C and RAD51D provide evidence for these primary mutations in conferring PARPi sensitivity and secondary mutations as a mechanism of acquired PARPi resistance. PARPi resistance due to secondary mutations underpins the need for early delivery of PARPi therapy and for combination strategies. Cancer Discov; 7(9); 984-98. ©2017 AACR.See related commentary by Domchek, p. 937See related article by Quigley et al., p. 999See related article by Goodall et al., p. 1006This article is highlighted in the In This Issue feature, p. 920.
Collapse
Affiliation(s)
- Olga Kondrashova
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Victoria, Australia
| | | | - Kristy Shield-Artin
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Anna V Tinker
- British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | | | | | - Michael J Kuiper
- Melbourne Bioinformatics, The University of Melbourne, Melbourne, Victoria, Australia
| | - Gwo-Yaw Ho
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Victoria, Australia
- Department of Medical Oncology, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| | - Holly Barker
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Rohit Prakash
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Elizabeth M Kass
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Meghan R Sullivan
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Gregory J Brunette
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Kara A Bernstein
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Robert L Coleman
- The University of Texas MD Anderson Cancer Center, Houston, Texas
| | | | - Michael Friedlander
- University of New South Wales and Prince of Wales Hospital, Sydney, New South Wales, Australia
| | | | | | - Amit Oza
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - James Sun
- Foundation Medicine, Inc., Cambridge, Massachusetts
| | | | | | | | | | - Matthew J Wakefield
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- Melbourne Bioinformatics, The University of Melbourne, Melbourne, Victoria, Australia
| | | | | | | | | | - Iain A McNeish
- Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | | | | | - Clare L Scott
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia.
- Department of Medical Biology, The University of Melbourne, Melbourne, Victoria, Australia
- Department of Medical Oncology, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| |
Collapse
|
6
|
Sullivan MR, Prakash R, Jasin M, Bernstein KA. Abstract A10: The impact of cancer-associated RAD51C mutations in homologous recombination. Mol Cancer Res 2017. [DOI: 10.1158/1557-3125.dnarepair16-a10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Homologous recombination (HR) is a major pathway for the repair of DNA double-strand breaks (DSBs). Loss of function of key HR repair proteins have been linked to diseases characterized by genomic instability including cancers and Fanconi anemia. Regulation of RAD51 filaments is critical during HR repair and is mediated by several factors including the RAD51 paralogs, a group of proteins that share sequence homology with RAD51. The RAD51 paralog family consists of five proteins in humans, RAD51B, RAD51C, RAD51D, XRCC2, and XRCC3. The RAD51 paralog, RAD51C, has recently become a key protein of interest as RAD51C mutations have been linked to familial breast and ovarian cancers. However, the specific functions of RAD51C have remained enigmatic as mouse and non-tumorigenic knockout models are inviable. Given these limitations, we have identified RAD51C point mutations from breast and ovarian cancer patients to study the phenotypes of these RAD51C mutants and how they impair homologous recombination. We have found that RAD51C mutations can disrupt interactions with RAD51 paralog binding partners, RAD51B and XRCC3, required for RAD51C stability. Through yeast-two/three-hybrid and co-immunoprecipitation experiments, we isolated RAD51C mutations that disrupt interactions within RAD51 paralog complexes. These complexes have important roles in the repair of classical DSBs induced by ionizing radiation or chemotherapeutic reagents as well as in replication fork protection such as after replication stress induced by hydroxyurea. Using RAD51C mutants to complement a conditional knockout model, we investigated how the roles of RAD51C were impacted by point mutations in response to these diverse substrates to ultimately understand how tumors with RAD51C mutations can be best targeted for treatment.
Citation Format: Meghan R. Sullivan, Rohit Prakash, Maria Jasin, Kara A. Bernstein. The impact of cancer-associated RAD51C mutations in homologous recombination [abstract]. In: Proceedings of the AACR Special Conference on DNA Repair: Tumor Development and Therapeutic Response; 2016 Nov 2-5; Montreal, QC, Canada. Philadelphia (PA): AACR; Mol Cancer Res 2017;15(4_Suppl):Abstract nr A10.
Collapse
Affiliation(s)
| | - Rohit Prakash
- 2Memorial Sloan Kettering Cancer Center, New York, NY
| | - Maria Jasin
- 2Memorial Sloan Kettering Cancer Center, New York, NY
| | | |
Collapse
|
7
|
Godin SK, Sullivan MR, Bernstein KA. Novel insights into RAD51 activity and regulation during homologous recombination and DNA replication. Biochem Cell Biol 2016; 94:407-418. [PMID: 27224545 DOI: 10.1139/bcb-2016-0012] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this review we focus on new insights that challenge our understanding of homologous recombination (HR) and Rad51 regulation. Recent advances using high-resolution microscopy and single molecule techniques have broadened our knowledge of Rad51 filament formation and strand invasion at double-strand break (DSB) sites and at replication forks, which are one of most physiologically relevant forms of HR from yeast to humans. Rad51 filament formation and strand invasion is regulated by many mediator proteins such as the Rad51 paralogues and the Shu complex, consisting of a Shu2/SWS1 family member and additional Rad51 paralogues. Importantly, a novel RAD51 paralogue was discovered in Caenorhabditis elegans, and its in vitro characterization has demonstrated a new function for the worm RAD51 paralogues during HR. Conservation of the human RAD51 paralogues function during HR and repair of replicative damage demonstrate how the RAD51 mediators play a critical role in human health and genomic integrity. Together, these new findings provide a framework for understanding RAD51 and its mediators in DNA repair during multiple cellular contexts.
Collapse
Affiliation(s)
- Stephen K Godin
- University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, and the Department of Microbiology and Molecular Genetics.,University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, and the Department of Microbiology and Molecular Genetics
| | - Meghan R Sullivan
- University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, and the Department of Microbiology and Molecular Genetics.,University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, and the Department of Microbiology and Molecular Genetics
| | - Kara A Bernstein
- University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, and the Department of Microbiology and Molecular Genetics
| |
Collapse
|
8
|
Böhm S, Szakal B, Herken BW, Sullivan MR, Mihalevic MJ, Kabbinavar FF, Branzei D, Clark NL, Bernstein KA. The Budding Yeast Ubiquitin Protease Ubp7 Is a Novel Component Involved in S Phase Progression. J Biol Chem 2016; 291:4442-52. [PMID: 26740628 DOI: 10.1074/jbc.m115.671057] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Indexed: 11/06/2022] Open
Abstract
DNA damage must be repaired in an accurate and timely fashion to preserve genome stability. Cellular mechanisms preventing genome instability are crucial to human health because genome instability is considered a hallmark of cancer. Collectively referred to as the DNA damage response, conserved pathways ensure proper DNA damage recognition and repair. The function of numerous DNA damage response components is fine-tuned by posttranslational modifications, including ubiquitination. This not only involves the enzyme cascade responsible for conjugating ubiquitin to substrates but also requires enzymes that mediate directed removal of ubiquitin. Deubiquitinases remove ubiquitin from substrates to prevent degradation or to mediate signaling functions. The Saccharomyces cerevisiae deubiquitinase Ubp7 has been characterized previously as an endocytic factor. However, here we identify Ubp7 as a novel factor affecting S phase progression after hydroxyurea treatment and demonstrate an evolutionary and genetic interaction of Ubp7 with DNA damage repair pathways of homologous recombination and nucleotide excision repair. We find that deletion of UBP7 sensitizes cells to hydroxyurea and cisplatin and demonstrate that factors that stabilize replication forks are critical under these conditions. Furthermore, ubp7Δ cells exhibit an S phase progression defect upon checkpoint activation by hydroxyurea treatment. ubp7Δ mutants are epistatic to factors involved in histone maintenance and modification, and we find that a subset of Ubp7 is chromatin-associated. In summary, our results suggest that Ubp7 contributes to S phase progression by affecting the chromatin state at replication forks, and we propose histone H2B ubiquitination as a potential substrate of Ubp7.
Collapse
Affiliation(s)
- Stefanie Böhm
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15213
| | - Barnabas Szakal
- the Department of Molecular Oncology, Fondazione Istituto Fondazione Italiana per la Ricerca sul Cancro di Oncologia Molecolare, Milan 20139, Italy
| | - Benjamin W Herken
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15213
| | - Meghan R Sullivan
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15213
| | - Michael J Mihalevic
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15213
| | - Faiz F Kabbinavar
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15213
| | - Dana Branzei
- the Department of Molecular Oncology, Fondazione Istituto Fondazione Italiana per la Ricerca sul Cancro di Oncologia Molecolare, Milan 20139, Italy
| | - Nathan L Clark
- the Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, and
| | - Kara A Bernstein
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15213,
| |
Collapse
|
9
|
Abstract
We propose the existence of a relationship of stereochemical complementarity between gene sequences that code for interacting components: nucleic acid-nucleic acid, protein-protein and protein-nucleic acid. Such a relationship would impose evolutionary constraints on the DNA sequences themselves, thus retaining these sequences and governing the direction of the evolutionary process. Therefore, we propose that prebiotic, template-directed autocatalytic synthesis of mutally cognate peptides and polynucleotides resulted in their amplification and evolutionary conservation in contemporary prokaryotic and eukaryotic organisms as a genetic regulatory apparatus. If this proposal is correct, then the relationships between the sequences in DNA coding for these interactions constitute a life code of which the genetic code is only one aspect of the many related interactions encoded in DNA.
Collapse
Affiliation(s)
- L F Harris
- David F. Hickok Memorial Cancer Research Laboratory, Abbott Northwestern Hospital, Minneapolis, MN 55407, USA.
| | | | | |
Collapse
|
10
|
Harris LF, Sullivan MR, Popken-Harris PD. Molecular dynamics simulation in solvent of the bacteriophage 434 cI repressor protein DNA binding domain amino acids (R1-69) in complex with its cognate operator (OR1) DNA sequence. J Biomol Struct Dyn 1999; 17:1-17. [PMID: 10496417 DOI: 10.1080/07391102.1999.10508336] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [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: 10/28/2022]
Abstract
We investigated protein/DNA interactions, using molecular dynamics simulations computed between a 10 Angstom water layer model of the 434 cI Repressor protein DNA binding domain (DBD) amino acids (R1-69) and DNA of operator (OR1) and its flanks consisting of 28 nucleotide base pairs. Hydrogen bonding interactions were monitored. In addition, van der Waals and electrostatic interaction energies were calculated. Amino acids of the 434 cI repressor DNA recognition helix 3 formed both direct and water mediated hydrogen bonds at cognate codon-anticodon nucleotide base and backbone sites within the OR1 DNA major groove halfsites and flanking regions. In addition, hydrophilic amino acids within the loop between helix 3 and helix 4 have strong electrostatic attraction to codon-anticodon nucleotides located within the central nucleotides of the minor groove between the OR1 major groove halfsites. These interactions together induced significant structural changes in the operator DNA manifested by overtwisting of the central nucleotide base pairs and narrowing of the minor groove between the DNA major groove halfsites. Finally, these findings offer a code for site specific DNA recognition by the 434 cI repressor protein.
Collapse
Affiliation(s)
- L F Harris
- David F. Hickok Memorial Cancer Research Laboratory, Abbott Northwestern Hospital, Minneapolis, MN 55407, USA.
| | | | | |
Collapse
|
11
|
Cochran RA, Leonardi-Cattolica AA, Sullivan MR, Kincaid LA, Leise BS, Thompson DL, Godke RA. The effects of equine somatotropin (eST) on follicular development and circulating plasma hormone profiles in cyclic mares treated during different stages of the estrous cycle. Domest Anim Endocrinol 1999; 16:57-67. [PMID: 10081663 DOI: 10.1016/s0739-7240(98)00046-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The effects of exogenous equine somatotropin (eST) administration on ovarian activity and plasma hormone levels were evaluated on horse and pony mares. The objectives of this study were to determine the effects of eST on follicular development and circulating concentrations of leutinizing hormone (LH), estradiol, progesterone, and insulin-like growth factor I (IGF-I) in cyclic horse and pony mares. Sixteen mares received daily injections (i.m.) of eST at a concentration of 25 micrograms/kg body weight on either Days 6 through 12 (Treatment A) or 13 through 19 (Treatment B) postovulation. In addition, contemporary mares were similarly given the carrier vehicle and served as controls (Treatments C and D). Blood samples were collected at 24-hr intervals and ultrasonographic evaluations were performed on the ovaries of each mare at 48-hr intervals beginning on the first day of treatment and ending either on the day of ovulation or 5 d postovulation. Circulating levels of insulin-like growth factor-I (IGF-I) were increased in treated mares by Day 3 post-treatment (P < 0.05). Also, mares in Treatment B exhibited a decrease in plasma estradiol concentrations (P < 0.05) when compared with control mares on Days 1 through 5 postovulation of the post-treated estrous cycle. In addition, circulating leutinizing hormone levels were different for mares in Treatment A compared with controls on Days--8 through--1 pre-ovulation (P < 0.05). All follicles present on the ovaries of each mare were measured and placed into one of five categories based on their diameter. Neither the mean number of follicles per size category > or = 8 mm in diameter nor the mean follicular diameter within each size category differed among treatment and control mares. However, eST treatment significantly increased the number of follicles < or = 7 mm on the ovaries of mares treated early in the estrous cycle when compared with control mares on Days 3 and 7 post-treatment and at the onset of standing estrus.
Collapse
Affiliation(s)
- R A Cochran
- Department of Animal Science, Louisiana State University, Baton Rouge 70803, USA
| | | | | | | | | | | | | |
Collapse
|
12
|
Harris LF, Sullivan MR, Popken-Harris PD. Molecular dynamics simulation in solvent of the estrogen receptor protein DNA binding domain in complex with a non-consensus estrogen response element DNA sequence. J Biomol Struct Dyn 1997; 15:407-30. [PMID: 9439992 DOI: 10.1080/07391102.1997.10508956] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [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: 02/05/2023]
Abstract
We investigated protein/DNA interactions, using molecular dynamics simulations computed between a 10 Angstom water layer model of the estrogen receptor (ER) protein DNA binding domain (DBD) amino acids and DNA of a non-consensus estrogen response element (ERE) consisting of 29 nucleotide base pairs. This ERE nucleotide sequence occurs naturally upstream of the Xenopus laevis Vitelligenin A1 gene. The ER DBD is encoded by three exons. Namely, exons 2 and 3 which encode the two zinc binding motifs and a sequence of exon 4 which encodes a predicted alpha helix. We generated a computer model of the ER DBD using atomic coordinates derived from the average of 30 nuclear magnetic resonance (NMR) spectroscopy coordinate sets. Amino acids on the carboxyl end of the ER DBD were disordered in both X-ray crystallography and NMR determinations and no coordinates were reported. This disordered region includes 10 amino acids of a predicted alpha helix encoded in exon 4 at the exon 3/4 splice junction. These amino acids are known to be important in DNA binding and are also believed to function as a nuclear translocation signal sequence for the ER protein. We generated a computer model of the predicted alpha helix consisting of the 10 amino acids encoded in exon 4 and attached this helix to the carboxyl end of the ER DBD at the exon 3/4 splice junction site. We docked the ER DBD model within the DNA major groove halfsites of the 29 base pair non-consensus ERE and flanking nucleotides. We constructed a solvated model with the ER DBD/ERE complex surrounded by a ten Angstrom water layer and conducted molecular dynamics simulations. Hydrogen bonding interactions were monitored. In addition, van der Waals and electrostatic interaction energies were calculated. Amino acids of the ER DBD DNA recognition helix formed both direct and water mediated hydrogen bonds at cognate codon-anticodon nucleotide base and backbone sites within the ERE DNA right major groove halfsite. Amino acids of the ER DBD exon 4 encoded predicted alpha helix formed direct and water mediated H-bonds with base and backbone sites of their cognate codon-anticodon nucleotides within the minor grooves flanking the ERE DNA major groove halfsites. These interactions together induced bending of the DNA into the protein.
Collapse
Affiliation(s)
- L F Harris
- David F. Hickok Memorial Cancer Research Laboratory, Abbott Northwestern Hospital, Minneapolis, MN 55407, USA.
| | | | | |
Collapse
|
13
|
Stephen JP, Sullivan MR, Hicks RG, Burke DJ, Woodforth IJ, Crawford MR. Cotrel-dubousset instrumentation in children using simultaneous motor and somatosensory evoked potential monitoring. Spine (Phila Pa 1976) 1996; 21:2450-7. [PMID: 8923630 DOI: 10.1097/00007632-199611010-00008] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
STUDY DESIGN To record prospectively combined motor- and somatosensory-evoked potentials in children during scoliosis surgery using Cotrel-Dubousset instrumentation, without using special anesthetic or muscle relaxant regimens. OBJECTIVE To determine the outcome of scoliosis surgery guided by a new technique of monitoring motor- and somatosensory-evoked potentials simultaneously. SUMMARY OF BACKGROUND DATA Other techniques used to assess cord function generally are limited by special anesthetic requirements or assess only a limited part of the cord or monitor motor function separately from somatosensory function. METHODS Spinal cord function was monitored using epidural leads to record simultaneously the descending motor volley (by transcranial electrical stimulation) and the ascending somatosensory volley (by tibial nerve stimulation) at two spinal levels. RESULTS Combined motor- and sensory-evoked potentials were recorded successfully in 138 of 160 children (81%). Changes in evoked potential waveforms were seen in eight patients (5%), but resolved or lessened in response to appropriate measures. Curve correction was satisfactory, and there were no new postoperative deficits or worsening of preexisting deficits in any patient. CONCLUSION A spinal cord monitoring system is described that is safe, reliable, accurate, and makes it unnecessary to resort to the "wake-up" test.
Collapse
Affiliation(s)
- J P Stephen
- Department of Orthopedic Surgery, Prince of Wales Hospital, Sydney, Australia
| | | | | | | | | | | |
Collapse
|
14
|
Gough LL, Pratt BA, Rumsey SC, Stengl AM, Sullivan MR, Wilbourn CL. Quality control and quality assurance: two sides of the same coin. Qual Assur 1995; 4:348-50. [PMID: 8890365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- L L Gough
- Corning Hazleton Inc, Madison, WI 53707-7545, USA
| | | | | | | | | | | |
Collapse
|
15
|
Harris LF, Sullivan MR, Popken-Harris PD, Hickok DF. A one nanosecond molecular dynamics simulation of the glucocorticoid receptor protein in complex with a glucocorticoid response element DNA sequence in a 10 Angstrom water layer. J Biomol Struct Dyn 1995; 13:423-40. [PMID: 8825722 DOI: 10.1080/07391102.1995.10508852] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [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: 02/02/2023]
Abstract
We investigated protein/DNA interactions, using molecular dynamics simulations computed for one nanosecond, between a 10 Angstom water layer model of the glucocorticoid receptor (GR) DNA binding domain (DBD) amino acids and DNA of a glucocorticoid receptor response element (GRE) consisting of 29 nucleotide base pairs. Hydrogen bonding interactions were monitored. In addition, van der Waals and electrostatic interaction energies were calculated. Amino acids of the GR DBD DNA recognition helix formed both direct and water mediated hydrogen bonds at cognate codon-anticodon nucleotide base and backbone sites within the GRE DNA right major groove halfsite. Likewise amino acids in a beta strand structure adjacent to the DNA recognition helix formed both direct and water mediated hydrogen bonds at cognate codon-anticodon nucleotide base and backbone sites within both the GRE right and left major groove halfsites. In addition, amino acids within a predicted alpha helix located on the carboxyl terminus of the GR DBD interacted at codon-anticodon nucleotide sites on the DNA backbone of the GRE right major groove flanking nucleotides. These interactions together induced breakage of Watson-Crick nucleotide base pairing hydrogen bonds, resulting in significant structural changes and bending of the DNA into the protein.
Collapse
Affiliation(s)
- L F Harris
- Abbott Northwestern Hospital Cancer Research Laboratory, Minneapolis, MN 55407, USA
| | | | | | | |
Collapse
|
16
|
Stengl AM, Bronson DC, Gouch LL, Rumsey SC, Sullivan MR, Wilbourn CL. Good Laboratory Practices, Total Quality Management, and International Organization for Standardization: a foundation for excellence. Qual Assur 1995; 4:316-8. [PMID: 8890358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- A M Stengl
- Corning Hazleton Inc., Madison, WI 53707-7545, USA
| | | | | | | | | | | |
Collapse
|
17
|
Harris LF, Sullivan MR, Popken-Harris PD, Hickok DF. Molecular dynamics simulations in solvent of the glucocorticoid receptor protein in complex with a glucocorticoid response element DNA sequence. J Biomol Struct Dyn 1994; 12:249-70. [PMID: 7702769 DOI: 10.1080/07391102.1994.10508740] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [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: 01/26/2023]
Abstract
We investigated protein/DNA interactions, using molecular dynamics simulations computed in solvent, between the glucocorticoid receptor (GR) DNA binding domain (DBD) amino acids and DNA of a glucocorticoid receptor response element (GRE). We compared findings obtained from a fully solvated 80 Angstrom water droplet GR DBD/GRE model with those from a 10 Angstrom water layer GR DBD/GRE model. Hydrogen bonding interactions were monitored. In addition, van der Waals and electrostatic interaction energies were calculated. Molecular dynamics simulations from both models yielded similar findings; amino acids of the GR DBD DNA recognition helix formed both direct and water mediated hydrogen bonds at cognate codon/anticodon nucleotide base sites within the GRE right major groove halfsite. Likewise GR DBD amino acids in a beta strand structure adjacent to the DNA recognition helix formed both direct and water mediated hydrogen bonds at cognate codon/anticodon nucleotide base and backbone sites. We also investigated protein/DNA interactions with a 10 Angstrom water layer model consisting of the same GR DBD as above but with a predicted alpha helix attached to the carboxyl terminus of the GR DBD docked at the same GRE as above with additional flanking nucleotides. In this model, the interactions between amino acids of the DNA recognition helix and beta strand and nucleotides within the GRE right major groove halfsite were at cognate codon/anticodon nucleotide sites as found in the two models above. In addition, amino acids within the predicted alpha helix located on the carboxyl terminus of the GR DBD interacted at codon/anticodon nucleotide sites on the DNA backbone of the GRE flanking nucleotides. These interactions together induced breakage of Watson-Crick nucleotide base pairing hydrogen bonds, resulting in bending of the DNA, strand elongation and unwinding events similar to those described for helicases.
Collapse
Affiliation(s)
- L F Harris
- Abbott Northwestern Hospital Cancer Research Laboratory, Minneapolis, MN 55407
| | | | | | | |
Collapse
|
18
|
Abstract
We present findings of genetic information conservation between the glucocorticoid response element (GRE) DNA and the cDNA encoding the glucocorticoid receptor (GR) DNA-binding domain (DBD). The regions of nucleotide sub-sequence similarity to the GRE in the GR DBD occur specifically at nucleotide sequences on the ends of exons 3,4, and 5 at their splice junction sites. These sequences encode the DNA recognition helix on exon 3, a beta-strand on exon 4, and a putative alpha-helix on exon 5, respectively. The nucleotide sequence of exon 5 that encodes the putative alpha-helix located on the carboxyl terminus of the GR DBD shares sequence similarity with the flanking nucleotide regions of the GRE. We generated a computer model of the GR DBD using atomic coordinates derived from nuclear magnetic resonance spectroscopy to which we attached the exon 5-encoded putative alpha-helix. We docked this GR DBD structure at the 39-base-pair nucleotide sequence containing the GRE binding site and flanking nucleotides, which contained conserved genetic information. We observed that amino acids of the DNA recognition helix, the beta-strand, and the putative alpha-helix are spatially aligned with trinucleotides identical to their cognate codons within the GRE and its flanking nucleotides.
Collapse
Affiliation(s)
- L F Harris
- Abbott Northwestern Hospital Cancer Research Laboratory, Minneapolis, MN 55407-3799
| | | | | |
Collapse
|
19
|
Hwang SJ, Harris HW, Otuechere G, Yalla S, Sullivan MR, Kashgarian M, Benos DJ, Kleyman TR, Zeidel ML. Transport defects of rabbit inner medullary collecting duct cells in obstructive nephropathy. Am J Physiol 1993; 264:F808-15. [PMID: 8388652 DOI: 10.1152/ajprenal.1993.264.5.f808] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Urinary obstruction markedly reduces collecting duct Na+ reabsorption. To define the cellular mechanisms of this derangement in Na+ reabsorption in inner medullary collecting duct (IMCD) of obstructed kidneys, suspensions of intact IMCD cells and inner medulla plasma membranes (IMPM) were prepared from 24 h obstructed and untreated control kidneys. Oxygen consumption (QO2) studies revealed marked reductions in both amiloride-sensitive and ouabain-sensitive QO2 but not ouabain-insensitive QO2 in intact IMCD cells from obstructed, compared with control animals, indicating a reduction in oxygen-dependent transport activities of both the Na+ channel and the Na(+)-K(+)-adenosinetriphosphatase (ATPase). Amiloride-sensitive conductive 22Na+ uptake in intact IMCD cells from obstructed kidneys was significantly decreased by 45% at 10 s, 30 s, and 1-5 min (10 s: 2.42 +/- 0.63 vs. 4.49 +/- 0.64 nmol Na+ flux/mg protein, n = 7, P < 0.05; 1 min: 4.65 +/- 0.7 vs. 8.27 +/- 0.98 nmol Na+ flux/mg protein, n = 7, P < 0.05), indicating decreased activity of amiloride-sensitive Na+ channels in these cells. However, immunoblots of IMPM with antibodies to Na+ channel proteins did not show significant differences in content of Na+ channel proteins between membranes from obstructed and control groups. Ouabain-sensitive Na(+)-K(+)-ATPase activity in IMPM of obstructed kidneys was also reduced (61.1 +/- 18.1 vs. 152.6 +/- 25.8 nmol ATP degradation.min-1.mg protein-1, n = 6, P < 0.02), and immunoblots with monoclonal antibodies against the alpha 1- and beta-subunits of rabbit Na(+)-K(+)-ATPase showed a 51 +/- 7% reduction of both subunits in IMPM from obstructed kidneys (n = 4).(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- S J Hwang
- Research Service, West Roxbury Department of Veterans Affairs Medical Center, Massachusetts 02132
| | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Hwang SJ, Haas M, Harris HW, Silva P, Yalla S, Sullivan MR, Otuechere G, Kashgarian M, Zeidel ML. Transport defects of rabbit medullary thick ascending limb cells in obstructive nephropathy. J Clin Invest 1993; 91:21-8. [PMID: 8380811 PMCID: PMC329990 DOI: 10.1172/jci116173] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [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: 01/30/2023] Open
Abstract
To characterize the sodium transport defect responsible for salt wasting in obstructive nephropathy, the major sodium transporters in the medullary thick ascending limb (mTAL), the apical Na-K-2Cl cotransporter and the basolateral Na-K-ATPase, were studied in fresh suspensions of mTAL cells and outer medulla plasma membranes prepared from obstructed and untreated kidneys. Oxygen consumption (QO2) studies in intact cells revealed marked reductions in the inhibitory effects of both furosemide and ouabain on QO2 in cells from obstructed, as compared with control animals, indicating a reduction in activities of both the Na-K-2Cl cotransporter and the Na-K-ATPase. Saturable [3H]bumetanide binding was reduced in membranes isolated from obstructed kidneys, but the Kd for [3H]bumetanide was unchanged, indicating a decrease in the number of functional luminal Na-K-2Cl cotransporters in obstructed mTAL. Ouabain sensitive Na-K-ATPase activity in plasma membranes was also reduced, and immunoblots using specific monoclonal antibodies directed against the alpha and beta subunits of rabbit Na-K-ATPase showed decreased amounts of both subunits in outer medullas of obstructed kidney. A significant decrease in [3H]bumetanide binding was detected after 4 h of ureteral obstruction, whereas Na-K-ATPase activity at this time was still not different from control. We conclude that ureteral obstruction reduces the amounts of both luminal Na-K-2Cl cotransporter and basolateral Na-K-ATPase in mTAL of obstructed kidney and that these reductions contribute to the salt wasting observed after release of obstruction.
Collapse
Affiliation(s)
- S J Hwang
- Research Service, West Roxbury Department of Veterans Affairs Medical Center, Massachusetts 02132
| | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Abstract
Dermatofibrosarcoma is a relatively common, locally aggressive, soft tissue fibrous histiocytoma. Ignorance of its marked propensity for locally invasive growth can lead to inadequate excision, and patients often suffer multiple recurrences. We present a case of dermatofibrosarcoma arising on the hand, and discuss its natural history and proper surgical therapy.
Collapse
|
22
|
Goodman EN, Sandler BT, Sullivan MR. An endoscopic method for recording DC potentials in the upper gastrointestinal tract. Am J Gastroenterol 1975; 63:13-9. [PMID: 1119466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
An endoscopic sensing electrode for measuiring mucosal potential differences along the duodenum, stomach and esophagus is described. Potential profiles were plotted for 31 humans. The profiles of 11 patients with documented carcinoma differed in shape from the profiles of 20 reference subjects with no such documentiation. The profiles of all the reference subjects demonstrated a distinct concave shape with a single pronounced dip. On the other hand, carcinoma profiles did not manifest such a dip but were flattened out and/or manifested an undulatory trend.
Collapse
|
23
|
|
24
|
Pirruccello FW, Sullivan MR. Ossified stylohyoid ligament (epihyal bone): an unusual case. Dent Dig 1972; 78:126-9. [PMID: 4501377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
25
|
Pirruccello FW, Sullivan MR. Unilateral osteocardilaginous exostosis osteoma of the mandible and hyperostosis: report of a case. Dent Dig 1972; 78:76-82. [PMID: 4500449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
26
|
|
27
|
Goodman EN, Flood CA, Sandler BT, Sullivan MR. A method of studying motility in the esophagus by recording electrical potentials. Am J Dig Dis 1966; 11:958-62. [PMID: 5922629 DOI: 10.1007/bf02233085] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
|