1
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Pipe SW, Hermans C, Chitlur M, Carcao M, Castaman G, Davis JA, Ducore J, Dunn AL, Escobar M, Journeycake J, Khan O, Mahlangu J, Meeks SL, Mitha IH, Négrier C, Nowak-Göttl U, Recht M, Chrisentery-Singleton T, Stasyshyn O, Vilchevska KV, Martinez LV, Wang M, Windyga J, Young G, Alexander WA, Bonzo D, Macie C, Mitchell IS, Sauty E, Wilkinson TA, Shapiro AD. Eptacog beta efficacy and safety in the treatment and control of bleeding in paediatric subjects (<12 years) with haemophilia A or B with inhibitors. Haemophilia 2022; 28:548-556. [PMID: 35475308 PMCID: PMC9542908 DOI: 10.1111/hae.14563] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [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: 01/04/2022] [Revised: 03/12/2022] [Accepted: 03/27/2022] [Indexed: 01/19/2023]
Abstract
Introduction Eptacog beta is a new recombinant activated human factor VII bypassing agent approved in the United States for the treatment and control of bleeding in patients with haemophilia A or B with inhibitors 12 years of age or older. Aim To prospectively assess in a phase 3 clinical trial (PERSEPT 2) eptacog beta efficacy and safety for treatment of bleeding in children <12 years of age with haemophilia A or B with inhibitors. Methods Using a randomised crossover design, subjects received initial doses of 75 or 225 μg/kg eptacog beta followed by 75 μg/kg dosing at predefined intervals (as determined by clinical response) to treat bleeding episodes (BEs). Treatment success criteria included a haemostasis evaluation of ‘excellent’ or ‘good’ without use of additional eptacog beta, alternative haemostatic agent or blood product, and no increase in pain following the first ‘excellent’ or ‘good’ assessment. Results Treatment success proportions in 25 subjects (1–11 years) who experienced 546 mild or moderate BEs were 65% in the 75 μg/kg initial dose regimen (IDR) and 60% in the 225 μg/kg IDR 12 h following initial eptacog beta infusion. By 24 h, the treatment success proportions were 97% for the 75 μg/kg IDR and 98% for the 225 μg/kg IDR. No thrombotic events, allergic reactions, neutralising antibodies or treatment‐related adverse events were reported. Conclusion Both 75 and 225 μg/kg eptacog beta IDRs provided safe and effective treatment and control of bleeding in children <12 years of age.
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Affiliation(s)
| | - Cédric Hermans
- Cliniques Saint-Luc, Université Catholique de Louvain, Brussels, Belgium
| | - Meera Chitlur
- Children's Hospital of Michigan, Central Michigan University, Detroit, Michigan, USA
| | - Manuel Carcao
- The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Giancarlo Castaman
- Center for Bleeding Disorders and Coagulation, Careggi University Hospital, Florence, Italy
| | - Joanna A Davis
- Pediatric Hemophilia Treatment Center, University of Miami, Miami, Florida, USA
| | - Jonathan Ducore
- Hematology/Oncology Clinic, University of California at Davis, Sacramento, California, USA
| | - Amy L Dunn
- Nationwide Children's Hospital, Department of Pediatrics at The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Miguel Escobar
- University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Janna Journeycake
- Oklahoma Center for Bleeding and Clotting Disorders at OU Health, Oklahoma City, Oklahoma, USA
| | - Osman Khan
- Oklahoma Center for Bleeding and Clotting Disorders at OU Health, Oklahoma City, Oklahoma, USA
| | - Johnny Mahlangu
- Hemophilia Comprehensive Care Center, University of the Witwatersrand and National Health Laboratory Service, Johannesburg, South Africa
| | - Shannon L Meeks
- Emory University and Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta, Atlanta, Georgia, USA
| | | | | | - Ulrike Nowak-Göttl
- Institute of Clinical Chemistry, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Michael Recht
- American Thrombosis and Hemostasis Network, Rochester, New York, USA.,Oregon Health & Science University, Portland, Oregon, USA
| | | | | | | | | | - Michael Wang
- Hemophilia and Thrombosis Center, University of Colorado, Aurora, Colorado, USA
| | - Jerzy Windyga
- Department of Hemostasis Disorders and Internal Medicine, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Guy Young
- Children's Hospital Los Angeles, Los Angeles, California, USA.,Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | | | | | | | | | - Evelyne Sauty
- LFB, Laboratoire français du fractionnement et des biotechnologies, Les Ulis, France
| | | | - Amy D Shapiro
- Indiana Hemophilia and Thrombosis Center, Indianapolis, Indiana, USA
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2
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Escobar M, Castaman G, Boix SB, Callaghan M, Moerloose P, Ducore J, Hermans C, Journeycake J, Leissinger C, Luck J, Mahlangu J, Miesbach W, Mitha IH, Négrier C, Quon D, Recht M, Schved JF, Shapiro AD, Sidonio R, Srivastava A, Stasyshyn O, Vilchevska KV, Wang M, Young G, Alexander WA, Al‐Sabbagh A, Bonzo D, Macie C, Wilkinson TA, Kessler C. Cover Image. Haemophilia 2021. [DOI: 10.1111/hae.14463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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3
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Escobar M, Castaman G, Boix SB, Callaghan M, de Moerloose P, Ducore J, Hermans C, Journeycake J, Leissinger C, Luck J, Mahlangu J, Miesbach W, Mitha IH, Négrier C, Quon D, Recht M, Schved JF, Shapiro AD, Sidonio R, Srivastava A, Stasyshyn O, Vilchevska KV, Wang M, Young G, Alexander WA, Al-Sabbagh A, Bonzo D, Macie C, Wilkinson TA, Kessler C. The safety of activated eptacog beta in the management of bleeding episodes and perioperative haemostasis in adult and paediatric haemophilia patients with inhibitors. Haemophilia 2021; 27:921-931. [PMID: 34636112 PMCID: PMC9292935 DOI: 10.1111/hae.14419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 04/13/2021] [Revised: 08/31/2021] [Accepted: 09/06/2021] [Indexed: 01/19/2023]
Abstract
Introduction Haemophilia patients with inhibitors often require a bypassing agent (BPA) for bleeding episode management. Eptacog beta (EB) is a new FDA‐approved recombinant activated human factor VII BPA for the treatment and control of bleeding in haemophilia A or B patients with inhibitors (≥12 years of age). We describe here the EB safety profile from the three prospective Phase 3 clinical trials performed to date. Aim To assess EB safety, immunogenicity and thrombotic potential in children and adults who received EB for treatment of bleeding and perioperative care. Methods Using a randomized crossover design, 27 subjects in PERSEPT 1 (12‐54 years) and 25 subjects in PERSEPT 2 (1‐11 years) treated bleeding episodes with 75 or 225 μg/kg EB initially followed by 75 μg/kg dosing at predefined intervals as determined by clinical response. Twelve PERSEPT 3 subjects (2‐56 years) received an initial preoperative infusion of 75 μg/kg (minor procedures) or 200 μg/kg EB (major surgeries) with subsequent 75 μg/kg doses administered intraoperatively and post‐operatively as indicated. Descriptive statistics were used for data analyses. Results Sixty subjects who received 3388 EB doses in three trials were evaluated. EB was well tolerated, with no allergic, hypersensitivity, anaphylactic or thrombotic events reported and no neutralizing anti‐EB antibodies detected. A death occurred during PERSEPT 3 and was determined to be unlikely related to EB treatment by the data monitoring committee. Conclusion Results from all three Phase 3 trials establish an excellent safety profile of EB in haemophilia A or B patients with inhibitors for treatment of bleeding and perioperative use.
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Affiliation(s)
- Miguel Escobar
- Gulf States Hemophilia and Thrombophilia Center, Houston, Texas, USA
| | - Giancarlo Castaman
- Center for Bleeding Disorders and Coagulation, Careggi University Hospital, Florence, Italy
| | | | | | | | - Jonathan Ducore
- Hematology/Oncology Clinic, University of California at Davis, Sacramento, California, USA
| | - Cédric Hermans
- Cliniques Saint-Luc, Université Catholique de Louvain, Brussels, Belgium
| | - Janna Journeycake
- Oklahoma Bleeding and Clotting Disorders Center at OU Health, Oklahoma City, Oklahoma, USA
| | - Cindy Leissinger
- Section of Hematology/Oncology, Tulane University School of Medicine, New Orleans, Louisiana, USA
| | - James Luck
- Orthopaedic Hemophilia Treatment Center, Los Angeles, California, USA
| | - Johnny Mahlangu
- Hemophilia Comprehensive Care Center, University of the Witwatersrand and National Health Laboratory Service, Johannesburg, South Africa
| | | | | | | | - Doris Quon
- Orthopaedic Hemophilia Treatment Center, Los Angeles, California, USA
| | - Michael Recht
- American Thrombosis and Hemostasis Network, Rochester, New York, USA.,Oregon Health & Science University, Portland, Oregon, USA
| | - Jean François Schved
- Haemophilia Treatment Centre, University Hospital Montpellier, Montpellier, France
| | - Amy D Shapiro
- Indiana Hemophilia and Thrombosis Center, Indianapolis, Indiana, USA
| | - Robert Sidonio
- Aflac Cancer and Blood Disorders Center, Emory University, Atlanta, Georgia, USA
| | | | | | | | - Michael Wang
- Hemophilia and Thrombosis Center, University of Colorado, Aurora, Colorado, USA
| | - Guy Young
- Children's Hospital Los Angeles, Los Angeles, California, USA.,Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | | | | | | | | | | | - Craig Kessler
- Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, District of Columbia, USA
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Escobar M, Luck J, Averianov Y, Ducore J, Fernández MFL, Giermasz A, Hart DP, Journeycake J, Kessler C, Leissinger C, Mahlangu J, Martinez LV, Miesbach W, Mitha IH, Quon D, Reding MT, Schved JF, Stasyshyn O, Vilchevska KV, Wang M, Windyga J, Alexander WA, Al-Sabbagh A, Bonzo D, Mitchell IS, Wilkinson TA, Hermans C. PERSEPT 3: A phase 3 clinical trial to evaluate the haemostatic efficacy of eptacog beta (recombinant human FVIIa) in perioperative care in subjects with haemophilia A or B with inhibitors. Haemophilia 2021; 27:911-920. [PMID: 34614267 PMCID: PMC9292306 DOI: 10.1111/hae.14418] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 05/14/2021] [Revised: 08/17/2021] [Accepted: 09/06/2021] [Indexed: 01/19/2023]
Abstract
INTRODUCTION Surgical procedures in persons with haemophilia A or B with inhibitors (PwHABI) require the use of bypassing agents (BPA) and carry a high risk of complications. Historically, only two BPAs have been available; these are reported to have variable responses. AIM To prospectively evaluate the efficacy and safety of a new bypassing agent, human recombinant factor VIIa (eptacog beta) in elective surgical procedures in PwHABI in a phase 3 clinical trial, PERSEPT 3. METHODS Subjects were administered 200 µg/kg (major procedures) or 75 µg/kg eptacog beta (minor procedures) immediately prior to the initial surgical incision; subsequent 75 µg/kg doses were administered to achieve postoperative haemostasis and wound healing. Efficacy was assessed on a 4-point haemostatic scale during the intra- and postoperative periods. Anti-drug antibodies, thrombotic events and changes in clinical/laboratory parameters were monitored throughout the perioperative period. RESULTS Twelve subjects underwent six major and six minor procedures. The primary efficacy endpoint success proportion was 100% (95% CI: 47.8%-100%) for minor procedures and 66.7% (95% CI: 22.3%-95.7%) for major procedures; 81.8% (95% CI: 48.2%-97.7%) of the procedures were considered successful using eptacog beta. There was one death due to bleeding from a nonsurgical site; this was assessed as unlikely related to eptacog beta. No thrombotic events or anti-eptacog beta antibodies were reported. CONCLUSION Two eptacog beta dosing regimens in PwHABI undergoing major and minor surgical procedures were well-tolerated, and the majority of procedures were successful based on surgeon/investigator assessments. Eptacog beta offers clinicians a new potential therapeutic option for procedures in PwHABI.
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Affiliation(s)
- Miguel Escobar
- Gulf States Hemophilia and Thrombophilia Center, Houston, Texas, USA
| | - James Luck
- Orthopaedic Hemophilia Treatment Center, Los Angeles, California, USA
| | - Yevhenii Averianov
- City Research and Development Center for Diagnostics and Treatment of Patients with Abnormal Hemostasis, Kyiv, Ukraine
| | - Jonathan Ducore
- Hematology/Oncology Clinic, University of California at Davis, Sacramento, California, USA
| | | | - Adam Giermasz
- Division of Hematology/Oncology, University of California at Davis, Sacramento, California, USA
| | - Daniel P Hart
- The Royal London Hospital Haemophilia Centre, Barts and The London School of Medicine and Dentistry, QMUL, London, UK
| | - Janna Journeycake
- Oklahoma Center for Bleeding and Clotting Disorders, Oklahoma City, Oklahoma, USA
| | - Craig Kessler
- Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, District of Columbia, USA
| | - Cindy Leissinger
- Section of Hematology/Oncology, Tulane University School of Medicine, New Orleans, Louisiana, USA
| | - Johnny Mahlangu
- Hemophilia Comprehensive Care Center, University of the Witwatersrand and National Health Laboratory Service, Johannesburg, South Africa
| | | | | | | | - Doris Quon
- Orthopaedic Hemophilia Treatment Center, Los Angeles, California, USA
| | - Mark T Reding
- Center for Bleeding and Clotting Disorders, University of Minnesota Medical Center, Minneapolis, Minnesota, USA
| | - Jean-François Schved
- Haemophilia Treatment Centre, University Hospital Montpellier, Montpellier, France
| | | | | | - Michael Wang
- Hemophilia and Thrombosis Center, University of Colorado, Aurora, Colorado, USA
| | - Jerzy Windyga
- Department of Hemostasis Disorders and Internal Medicine, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | | | | | | | | | | | - Cédric Hermans
- Cliniques Saint-Luc, Université Catholique de Louvain, Brussels, Belgium
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5
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Cohen R, Borzutzky C, Wilkinson TA, Thompson M, Collins J. POSTER ABSTRACTS. Contraception 2021. [DOI: 10.1016/j.contraception.2021.07.096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Wilkinson TA, Maurer CE, Flood CJ, Lander G, Chafin S, Flagg EB. Complete Stokes vector analysis with a compact, portable rotating waveplate polarimeter. Rev Sci Instrum 2021; 92:093101. [PMID: 34598489 DOI: 10.1063/5.0052835] [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] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 08/14/2021] [Indexed: 06/13/2023]
Abstract
Accurate calibration of polarization-dependent optical elements is often necessary in optics experiments. A versatile polarimeter device to measure the polarization state of light is a valuable tool in these experiments. Here, we report a rotating waveplate-based polarimeter capable of complete Stokes vector analysis of collimated light. Calibration of the device allows accurate measurements over a range of wavelengths, with a bandwidth of >30 nm in this implementation. A photo-interrupter trigger system supplies the phase information necessary for full determination of the Stokes vector. An Arduino microcontroller performs rapid analysis and displays the results on a liquid crystal display. The Arduino can also be interfaced with a computer to store time series of Stokes vectors. The optical measurement apparatus of the polarimeter is compact and can be placed anywhere on an optical table on a single standard post. The components to construct the device are only a fraction of the cost of commercially available devices, while the accuracy and precision of the measurements are of the same order of magnitude.
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Affiliation(s)
- T A Wilkinson
- Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506, USA
| | - C E Maurer
- Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506, USA
| | - C J Flood
- Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506, USA
| | - G Lander
- Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506, USA
| | - S Chafin
- Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506, USA
| | - E B Flagg
- Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506, USA
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Horie M, Castaldi A, Sunohara M, Wang H, Ji Y, Liu Y, Li F, Wilkinson TA, Hung L, Shen H, Kage H, Offringa IA, Marconett CN, Flodby P, Zhou B, Borok Z. Integrated Single-Cell RNA-Sequencing Analysis of Aquaporin 5-Expressing Mouse Lung Epithelial Cells Identifies GPRC5A as a Novel Validated Type I Cell Surface Marker. Cells 2020; 9:cells9112460. [PMID: 33187367 PMCID: PMC7697677 DOI: 10.3390/cells9112460] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [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: 09/19/2020] [Revised: 10/30/2020] [Accepted: 11/05/2020] [Indexed: 12/01/2022] Open
Abstract
Molecular and functional characterization of alveolar epithelial type I (AT1) cells has been challenging due to difficulty in isolating sufficient numbers of viable cells. Here we performed single-cell RNA-sequencing (scRNA-seq) of tdTomato+ cells from lungs of AT1 cell-specific Aqp5-Cre-IRES-DsRed (ACID);R26tdTomato reporter mice. Following enzymatic digestion, CD31-CD45-E-cadherin+tdTomato+ cells were subjected to fluorescence-activated cell sorting (FACS) followed by scRNA-seq. Cell identity was confirmed by immunofluorescence using cell type-specific antibodies. After quality control, 92 cells were analyzed. Most cells expressed ‘conventional’ AT1 cell markers (Aqp5, Pdpn, Hopx, Ager), with heterogeneous expression within this population. The remaining cells expressed AT2, club, basal or ciliated cell markers. Integration with public datasets identified three robust AT1 cell- and lung-enriched genes, Ager, Rtkn2 and Gprc5a, that were conserved across species. GPRC5A co-localized with HOPX and was not expressed in AT2 or airway cells in mouse, rat and human lung. GPRC5A co-localized with AQP5 but not pro-SPC or CC10 in mouse lung epithelial cell cytospins. We enriched mouse AT1 cells to perform molecular phenotyping using scRNA-seq. Further characterization of putative AT1 cell-enriched genes revealed GPRC5A as a conserved AT1 cell surface marker that may be useful for AT1 cell isolation.
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Affiliation(s)
- Masafumi Horie
- Hastings Center for Pulmonary Research and Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA; (M.H.); (A.C.); (M.S.); (H.W.); (Y.J.); (Y.L.); (H.S.); (P.F.); (B.Z.)
| | - Alessandra Castaldi
- Hastings Center for Pulmonary Research and Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA; (M.H.); (A.C.); (M.S.); (H.W.); (Y.J.); (Y.L.); (H.S.); (P.F.); (B.Z.)
| | - Mitsuhiro Sunohara
- Hastings Center for Pulmonary Research and Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA; (M.H.); (A.C.); (M.S.); (H.W.); (Y.J.); (Y.L.); (H.S.); (P.F.); (B.Z.)
- Department of Respiratory Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan;
- Division for Health Service Promotion, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hongjun Wang
- Hastings Center for Pulmonary Research and Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA; (M.H.); (A.C.); (M.S.); (H.W.); (Y.J.); (Y.L.); (H.S.); (P.F.); (B.Z.)
| | - Yanbin Ji
- Hastings Center for Pulmonary Research and Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA; (M.H.); (A.C.); (M.S.); (H.W.); (Y.J.); (Y.L.); (H.S.); (P.F.); (B.Z.)
| | - Yixin Liu
- Hastings Center for Pulmonary Research and Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA; (M.H.); (A.C.); (M.S.); (H.W.); (Y.J.); (Y.L.); (H.S.); (P.F.); (B.Z.)
| | - Fan Li
- Single-Cell, Sequencing, and CyTOF Core (SC2), Children’s Hospital Los Angeles, Los Angeles, CA 90027, USA; (F.L.); (T.A.W.); (L.H.)
| | - Thomas A. Wilkinson
- Single-Cell, Sequencing, and CyTOF Core (SC2), Children’s Hospital Los Angeles, Los Angeles, CA 90027, USA; (F.L.); (T.A.W.); (L.H.)
| | - Long Hung
- Single-Cell, Sequencing, and CyTOF Core (SC2), Children’s Hospital Los Angeles, Los Angeles, CA 90027, USA; (F.L.); (T.A.W.); (L.H.)
| | - Hua Shen
- Hastings Center for Pulmonary Research and Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA; (M.H.); (A.C.); (M.S.); (H.W.); (Y.J.); (Y.L.); (H.S.); (P.F.); (B.Z.)
| | - Hidenori Kage
- Department of Respiratory Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan;
| | - Ite A. Offringa
- Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA; (I.A.O.); (C.N.M.)
- USC Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
- Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Crystal N. Marconett
- Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA; (I.A.O.); (C.N.M.)
- USC Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
- Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Per Flodby
- Hastings Center for Pulmonary Research and Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA; (M.H.); (A.C.); (M.S.); (H.W.); (Y.J.); (Y.L.); (H.S.); (P.F.); (B.Z.)
| | - Beiyun Zhou
- Hastings Center for Pulmonary Research and Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA; (M.H.); (A.C.); (M.S.); (H.W.); (Y.J.); (Y.L.); (H.S.); (P.F.); (B.Z.)
- USC Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Zea Borok
- Hastings Center for Pulmonary Research and Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA; (M.H.); (A.C.); (M.S.); (H.W.); (Y.J.); (Y.L.); (H.S.); (P.F.); (B.Z.)
- USC Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
- Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
- Correspondence: ; Tel.: +323-409-7184; Fax: +323-226-2738
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Bender JM, Li F, Adisetiyo H, Lee D, Zabih S, Hung L, Wilkinson TA, Pannaraj PS, She RC, Bard JD, Tobin NH, Aldrovandi GM. Quantification of variation and the impact of biomass in targeted 16S rRNA gene sequencing studies. Microbiome 2018; 6:155. [PMID: 30201048 PMCID: PMC6131952 DOI: 10.1186/s40168-018-0543-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Accepted: 08/29/2018] [Indexed: 05/20/2023]
Abstract
BACKGROUND Recent advances in sequencing technologies and bioinformatics tools have allowed for large-scale microbiome studies that are rapidly advancing medical research. However, small changes in technique or analysis can significantly alter the results and lead to conflicting findings. Quantifying the technical versus biological variation expected in targeted 16S rRNA gene sequencing studies and how this variation changes with input biomass is critical to guide meaningful interpretation of the current literature and plan future research. RESULTS Data were compiled from 469 sequencing libraries across 19 separate targeted 16S rRNA gene sequencing runs over a 2.5-year time period. Following removal of contaminant sequences identified from negative controls, 244 samples retained sufficient reads for further analysis. Coefficients of variation for intra- and inter-assay variation from repeated measurements of a bacterial mock community ranged from 8.7 to 37.6% (intra) and 15.6 to 80.5% (inter) for all but one genus of bacteria whose relative abundance was greater than 1%. Intra- versus inter-assay Bray-Curtis pairwise distances for a single stool sample were 0.11 versus 0.31, whereas intra-assay variation from repeat stool samples from the same donor was greater at 0.38 (Wilcoxon p = 0.001). A dilution series of the bacterial mock community was used to assess the effect of input biomass on variability. Pairwise distances increased with more dilute samples, and estimates of relative abundance became unreliable below approximately 100 copies of the 16S rRNA gene per microliter. Using this data, we created a prediction model to estimate the expected variation in microbiome measurements for given input biomass and relative abundance values. CONCLUSIONS Well-controlled microbiome studies are sufficiently robust to capture small biological effects and can achieve levels of variability consistent with clinical assays. Relative abundance is negatively associated with measures of variability and has a stronger effect on variability than does absolute biomass, suggesting that it is feasible to detect differences in bacterial populations in very low-biomass samples. Further, by quantifying the effect of biomass and relative abundance on compositional variability, we developed a tool for defining the expected variance in a given microbiome study.
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Affiliation(s)
- Jeffrey M. Bender
- USC Keck School of Medicine and Children’s Hospital Los Angeles, 4650 Sunset Blvd, Los Angeles, CA 90027 USA
| | - Fan Li
- Children’s Hospital Los Angeles, 4650 Sunset Blvd, Los Angeles, CA 90027 USA
| | - Helty Adisetiyo
- Children’s Hospital Los Angeles, 4650 Sunset Blvd, Los Angeles, CA 90027 USA
| | - David Lee
- David Geffen School of Medicine at UCLA, 10833 Le Conte Ave, Los Angeles, CA 90095 USA
| | - Sara Zabih
- David Geffen School of Medicine at UCLA, 10833 Le Conte Ave, Los Angeles, CA 90095 USA
| | - Long Hung
- Children’s Hospital Los Angeles, 4650 Sunset Blvd, Los Angeles, CA 90027 USA
| | - Thomas A. Wilkinson
- Children’s Hospital Los Angeles, 4650 Sunset Blvd, Los Angeles, CA 90027 USA
| | - Pia S. Pannaraj
- USC Keck School of Medicine and Children’s Hospital Los Angeles, 4650 Sunset Blvd, Los Angeles, CA 90027 USA
| | - Rosemary C. She
- USC Keck School of Medicine, 1975 Zonal Ave, Los Angeles, CA 90033 USA
| | - Jennifer Dien Bard
- USC Keck School of Medicine and Children’s Hospital Los Angeles, 4650 Sunset Blvd, Los Angeles, CA 90027 USA
| | - Nicole H. Tobin
- David Geffen School of Medicine at UCLA, 10833 Le Conte Ave, Los Angeles, CA 90095 USA
| | - Grace M. Aldrovandi
- David Geffen School of Medicine at UCLA, 10833 Le Conte Ave, Los Angeles, CA 90095 USA
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9
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Nakamura KJ, Heath L, Sobrera ER, Wilkinson TA, Semrau K, Kankasa C, Tobin NH, Webb NE, Lee B, Thea DM, Kuhn L, Mullins JI, Aldrovandi GM. Breast milk and in utero transmission of HIV-1 select for envelope variants with unique molecular signatures. Retrovirology 2017; 14:6. [PMID: 28122636 PMCID: PMC5267468 DOI: 10.1186/s12977-017-0331-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [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: 08/17/2016] [Accepted: 01/12/2017] [Indexed: 01/06/2023] Open
Abstract
Background Mother-to-child transmission of human immunodeficiency virus-type 1 (HIV-1) poses a serious health threat in developing countries, and adequate interventions are as yet unrealized. HIV-1 infection is frequently initiated by a single founder viral variant, but the factors that influence particular variant selection are poorly understood. Results Our analysis of 647 full-length HIV-1 subtype C and G viral envelope sequences from 22 mother–infant pairs reveals unique genotypic and phenotypic signatures that depend upon transmission route. Relative to maternal strains, intrauterine HIV transmission selects infant variants that have shorter, less-glycosylated V1 loops that are more resistant to soluble CD4 (sCD4) neutralization. Transmission through breastfeeding selects for variants with fewer potential glycosylation sites in gp41, are more sensitive to the broadly neutralizing antibodies PG9 and PG16, and that bind sCD4 with reduced cooperativity. Furthermore, experiments with Affinofile cells indicate that infant viruses, regardless of transmission route, require increased levels of surface CD4 receptor for productive infection. Conclusions These data provide the first evidence for transmission route-specific selection of HIV-1 variants, potentially informing therapeutic strategies and vaccine designs that can be tailored to specific modes of vertical HIV transmission. Electronic supplementary material The online version of this article (doi:10.1186/s12977-017-0331-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kyle J Nakamura
- Division of Infectious Diseases, Children's Hospital Los Angeles, Los Angeles, CA, USA.,Systems Biology and Disease Program, USC Keck School of Medicine, Los Angeles, CA, USA
| | - Laura Heath
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Edwin R Sobrera
- Division of Infectious Diseases, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Thomas A Wilkinson
- Division of Infectious Diseases, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Katherine Semrau
- Division of Global Health Equity, Brigham and Women's Hospital, Harvard Medical School, and Ariadne Labs, Boston, MA, USA
| | - Chipepo Kankasa
- University Teaching Hospital, University of Zambia, Lusaka, Zambia
| | - Nicole H Tobin
- Division of Pediatric Infectious Diseases, Department of Pediatrics, David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, CA, USA
| | - Nicholas E Webb
- Division of Pediatric Infectious Diseases, Department of Pediatrics, David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, CA, USA
| | - Benhur Lee
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Donald M Thea
- Division of Global Health Equity, Brigham and Women's Hospital, Harvard Medical School, and Ariadne Labs, Boston, MA, USA
| | - Louise Kuhn
- Department of Epidemiology, Columbia University, New York, NY, USA
| | - James I Mullins
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Grace M Aldrovandi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, CA, USA.
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10
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Chow SA, Wilkinson TA, Zhang M, Januszyk K, Phillips ML, Le Grice SFJ, Clubb RT. Specific HIV‐1 integrase‐reverse transcriptase interactions as a mechanism for promoting reverse transcription. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.501.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Samson A. Chow
- Molecular and Medical PharmacologyUCLA School of MedicineLos AngelesCA
| | | | - Min Zhang
- Molecular and Medical PharmacologyUCLA School of MedicineLos AngelesCA
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11
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Wilkinson TA, Januszyk K, Phillips ML, Tekeste SS, Zhang M, Miller JT, Le Grice SFJ, Clubb RT, Chow SA. Identifying and characterizing a functional HIV-1 reverse transcriptase-binding site on integrase. J Biol Chem 2009; 284:7931-9. [PMID: 19150986 DOI: 10.1074/jbc.m806241200] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Integrase (IN) from human immunodeficiency virus, type 1 (HIV-1) exerts pleiotropic effects in the viral replication cycle. Besides integration, IN mutations can impact nuclear import, viral maturation, and reverse transcription. IN and reverse transcriptase (RT) interact in vitro, and the IN C-terminal domain (CTD) is both necessary and sufficient for binding RT. We used nuclear magnetic resonance spectroscopy to identify a putative RT-binding surface on the IN CTD, and surface plasmon resonance to obtain kinetic parameters and the binding affinity for the IN-RT interaction. An IN K258A substitution that disrupts reverse transcription in infected cells is located at the putative RT-binding surface, and we found that this substitution substantially weakens IN CTD-RT interactions. We also identified two additional IN amino acid substitutions located at the putative RT-binding surface (W243E and V250E) that significantly impair viral replication in tissue culture. These results strengthen the notion that IN-RT interactions are biologically relevant during HIV-1 replication and also provide insights into this interaction at the molecular level.
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Affiliation(s)
- Thomas A Wilkinson
- Department of Molecular & Medical Pharmacology, University of California, Los Angeles, California 90095, USA
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12
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Vatakis DN, Bristol G, Wilkinson TA, Chow SA, Zack JA. Immediate activation fails to rescue efficient human immunodeficiency virus replication in quiescent CD4+ T cells. J Virol 2007; 81:3574-82. [PMID: 17229711 PMCID: PMC1866069 DOI: 10.1128/jvi.02569-06] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [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: 11/20/2022] Open
Abstract
Unlike activated T cells, quiescent CD4+ T cells have shown resistance to human immunodeficiency virus (HIV) infection due to a block in the early events of the viral life cycle. To further investigate the nature of this block, we infected quiescent CD4+ T cells with HIV-1(NL4-3) and immediately stimulated them. Compared to activated (prestimulated) cells, these poststimulated cells showed slightly decreased viral entry and delays in the completion of reverse transcription. However, the relative efficiency of integration was similar to that of prestimulated cells. Together, this resulted in decreased expression of tat/rev mRNA and synthesis of viral protein. Furthermore, based on cell cycle staining and BrdU incorporation, poststimulated cells expressing viral protein failed to initiate a second round of their cell cycle, independently of Vpr-mediated arrest. Together, these data demonstrate that the early stages of the HIV life cycle are inefficient in these poststimulated cells and that efficient replication cannot be induced by subsequent activation.
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Affiliation(s)
- Dimitrios N Vatakis
- David Geffen School of Medicine at UCLA, 650 Charles Young Dr. South, Box 951678, 11-934 Factor, Los Angeles, CA 90095-1678, USA
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13
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Tan W, Dong Z, Wilkinson TA, Barbas CF, Chow SA. Human immunodeficiency virus type 1 incorporated with fusion proteins consisting of integrase and the designed polydactyl zinc finger protein E2C can bias integration of viral DNA into a predetermined chromosomal region in human cells. J Virol 2006; 80:1939-48. [PMID: 16439549 PMCID: PMC1367172 DOI: 10.1128/jvi.80.4.1939-1948.2006] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [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: 10/26/2005] [Accepted: 12/01/2005] [Indexed: 12/31/2022] Open
Abstract
In vitro studies using fusion proteins consisting of human immunodeficiency virus type 1 integrase (IN) and a synthetic polydactyl zinc finger protein E2C, a sequence-specific DNA-binding protein, showed that integration of retroviral DNA can be biased towards a contiguous 18-bp E2C-recognition site. To determine whether the fusion protein strategy can achieve site-specific integration in vivo, viruses were prepared by cotransfection and various IN-E2C fusion proteins were packaged in trans into virions. The resulting viruses incorporated with the IN-E2C fusion proteins were functional and capable of performing integration at a level ranging from 1 to 24% of that of viruses containing wild-type (WT) IN. Two of the more infectious viruses, which contained E2C fused to either the N (E2C/IN) or to the C (IN/E2C) terminus of IN, were tested for their ability to direct integration into a unique E2C-binding site present within the 5' untranslated region of erbB-2 gene on human chromosome 17. The copy number of proviral DNA was measured using a quantitative real-time nested-PCR assay, and the specificity of directed integration was determined by comparing the number of proviruses within the vicinity of the E2C-binding site to that in the whole genome. Viruses containing IN/E2C fusion proteins had sevenfold higher preference for integrating near the E2C-binding site than those viruses containing WT IN, whereas viruses containing E2C/IN had 10-fold higher preference. The results indicated that the IN-E2C fusion protein strategy is capable of directing integration of retroviral DNA into a predetermined chromosomal region in the human genome.
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Affiliation(s)
- Wenjie Tan
- Department of Molecular and Medical Pharmacology, Molecular Biology Institute, and UCLA AIDS Institute, UCLA School of Medicine, Los Angeles, CA 90095, USA
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Wilkinson TA, Tellinghuisen TL, Kuhn RJ, Post CB. Association of sindbis virus capsid protein with phospholipid membranes and the E2 glycoprotein: implications for alphavirus assembly. Biochemistry 2005; 44:2800-10. [PMID: 15723524 DOI: 10.1021/bi0479961] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [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: 11/29/2022]
Abstract
A late stage in assembly of alphaviruses within infected cells is thought to be directed by interactions between the nucleocapsid and the cytoplasmic domain of the E2 protein, a component of the viral E1/E2 glycoprotein complex that is embedded in the plasma membrane. Recognition between the nucleocapsid protein and the E2 protein was explored in solution using NMR spectroscopy, as well as in binding assays using a model phospholipid membrane system that incorporated a variety of Sindbis virus E2 cytoplasmic domain (cdE2) and capsid protein constructs. In these binding assays, synthetic cdE2 peptides were reconstituted into phospholipid vesicles to simulate the presentation of cdE2 on the inner leaflet of the plasma membrane. Results from these binding assays showed a direct interaction between a peptide containing the C-terminal 16 amino acids of the cdE2 sequence and a Sindbis virus capsid protein construct containing amino acids 19-264. Additional experiments that probed the sequence specificity of this cdE2-capsid interaction are also described. Further binding assays demonstrated an interaction between the 19-264 capsid protein and artificial vesicles containing neutral or negatively charged phospholipids, while capsid protein constructs with N-terminal truncations displayed either little or no affinity for such vesicles. The membrane-binding property of the capsid protein suggests that the membrane may play an active role in alphavirus assembly. The results are consistent with an assembly process involving an initial membrane association, whereby an association with E2 glycoprotein further enhances capsid binding to facilitate membrane envelopment of the nucleocapsid for budding. Collectively, these experiments elucidate certain requirements for the binding of Sindbis virus capsid protein to the cytoplasmic domain of the E2 glycoprotein, a critical event in the alphavirus maturation pathway.
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Affiliation(s)
- Thomas A Wilkinson
- Department of Biological Sciences and the Markey Center for Structural Biology, Purdue University, West Lafayette, Indiana 47907, USA
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Abstract
Sequence-specific recognition between HIV-1 Rev and viral RNA mediates the nuclear export of the viral mRNA and thus is important for the viral life cycle. HIV Rev binds to its viral RNA target with high affinity and specificity and also binds to an in vitro selected RNA aptamer that has a significantly different sequence from the viral RNA target with a 6-fold higher affinity than its natural target. The high-resolution structures of HIV Rev Arg-rich motif (ARM) in complexes with the wild-type RNA and the RNA aptamer reveal that, despite the significantly different RNA sequences, the two complexes share similar structural features and the protein-RNA interactions are mediated mostly by the Arg side chains in Rev ARM. To gain further insight into the role of these Arg side chains in the sequence-specific protein-RNA recognition, we have characterized the flexibility of these Arg side chains at the interfaces of the two high-affinity complexes using (15)N R(1), R(2), nuclear Overhauser effect, and chemical-shift anisotropy dipolar cross-correlation relaxation measurements. The ARM peptide contains uniformly (13)C/(15)N-labeled Arg residues, and the RNA samples were unlabeled. Despite the apparently similar roles of Arg side chains in both complexes, most of them display a different dynamic behavior in the context of different RNA molecules, and extensive and highly diverse motions have been observed for all of these side chains that interact with RNA. Most of the differences in side-chain dynamics between the complexes cannot be inferred from the three-dimensional structures. Additionally, more than half of the residues have increased flexibility in the Rev-RNA aptamer complex that has a higher affinity. This study provides new insights into ARM-RNA recognition and indicates that retention of conformational flexibility is likely important in high-affinity ARM-RNA recognition.
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Affiliation(s)
- Thomas A Wilkinson
- Division of Immunology, Beckman Research Institute of the City of Hope National Medical Center, Duarte, California 91010, USA
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Abstract
Posttranslational modification by the ubiquitin homologue, small ubiquitin-like modifier 1 (SUMO-1), has been established as an important regulatory mechanism. However, in most cases it is not clear how sumoylation regulates various cellular functions. Emerging evidence suggests that sumoylation may play a general role in regulating protein-protein interactions, as shown in RanBP2/Nup358 and RanGAP1 interaction. In this study, we have defined an amino acid sequence motif that binds SUMO. This motif, V/I-X-V/I-V/I, was identified by NMR spectroscopic characterization of interactions among SUMO-1 and peptides derived from proteins that are known to bind SUMO or sumoylated proteins. This motif binds all SUMO paralogues (SUMO-1-3). Using site-directed mutagenesis, we also show that this SUMO-binding motif in RanBP2/Nup358 is responsible for the interaction between RanBP2/Nup358 and sumoylated RanGAP1. The SUMO-binding motif exists in nearly all proteins known to be involved in SUMO-dependent processes, suggesting its general role in sumoylation-dependent cellular functions.
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Affiliation(s)
- Jing Song
- Division of Immunology, Beckman Research Institute of the City of Hope, 1450 East Duarte Road, Duarte, CA 91010, USA
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17
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Wilkinson TA, Chen Y. Analysis of soluble sugar permease domains by solution NMR. Methods Mol Biol 2004; 227:321-34. [PMID: 12824656 DOI: 10.1385/1-59259-387-9:321] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Thomas A Wilkinson
- Division of Immunology, Beckman Research Institute of the City of Hope National Medical Center, Duarte, CA, USA
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Abstract
The binding of human immunodeficiency virus type 1 (HIV-1) Rev protein to its viral RNA target, stem-loop IIB (SLIIB) within the Rev Response element (RRE), mediates the export of singly-spliced and unspliced viral mRNA from the nucleus to the cytoplasm of infected cells; this Rev-mediated transport of viral RNA is absolutely required for the replication of infectious virus. To identify important features that influence the binding affinity and specificity of this Rev-RRE interaction, we have characterized the arginine side-chain dynamics of the Rev arginine-rich motif (ARM) while bound to a 34 nt RNA oligomer that corresponds to SLIIB. As the specificity of the Rev-RRE interaction varies with salt concentration, arginine side-chain dynamics were characterized at two different salt conditions. Following NMR measurements of (15)N spin relaxation parameters for the arginine (15)N(epsilon) nuclei, the dynamics of the corresponding N(epsilon)-H(epsilon) bond vectors were interpreted in terms of Lipari-Szabo model-free parameters using anisotropic expressions for the spectral density functions. Results from these analyses indicate that a number of arginine side-chains display a surprising degree of conformational freedom when bound to RNA, and that arginine residues having known importance for specific RRE recognition show striking differences in side-chain mobility. The (15)N relaxation measurements at different salt conditions suggest that the previously reported increase in Rev-RRE specificity at elevated salt concentrations is likely due to reduced affinity of non-specific Rev-RNA interactions. The observed dynamical behavior of the arginine side-chains at this protein-RNA interface likely plays an important role in the specificity and affinity of Rev-SLIIB complex formation.
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Affiliation(s)
- T A Wilkinson
- Division of Immunology, Beckman Research Institute of the City of Hope National Medical Center, Duarte, CA, 91010, USA
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Abstract
Numerous proteins that are involved in cell signaling and viral replication require post-translational modification by palmitoylation to function properly. The molecular details by which this palmitoyl modification affects protein function remain poorly understood. To facilitate in vitro biochemical and structural studies of the role of palmitoylation on protein function, a method was developed for alkylating peptides with saturated C16 groups at cysteine residues and demonstrated using peptides derived from the palmitoylated region of Sindbis virus E2 glycoprotein. The synthetic approach takes advantage of disulfide chemistry to specifically modify only the cysteine residues within peptides and covalently links C16 groups via disulfide bridges using a new thioalkylating reagent, hexyldexyldithiopyridine. The chemistry presented here takes place in solution under mild conditions without the need for protection of the peptide functional groups. A method for purifying these modified peptides is also described. This protocol can be of general use to investigators studying the role of palmitoylation in biological systems.
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Affiliation(s)
- T A Wilkinson
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907-1392, USA
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Wilkinson TA, James RS, Crolla JA, Cockwell AE, Campbell PL, Temple IK. A case of maternal uniparental disomy of chromosome 9 in association with confined placental mosaicism for trisomy 9. Prenat Diagn 1996; 16:371-4. [PMID: 8734817 DOI: 10.1002/(sici)1097-0223(199604)16:4<371::aid-pd866>3.0.co;2-s] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [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
We describe the first case of maternal uniparental disomy (UPD) of chromosome 9 in a fetus who was shown to have mosaic trisomy 9 in a chorionic villus sample. Karyotyping and molecular studies following termination of the pregnancy confirmed mosaicism in the placenta and maternal UPD(9) in the fetal tissues. This case demonstrates that the mechanism of trisomy correction may result in a fetus with UPD(9).
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Affiliation(s)
- T A Wilkinson
- Wessex Regional Genetics Laboratory, Salisbury District Hospital, Wiltshire, U.K
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Abstract
Three families in which a satellited Y chromosome (Yqs) was segregating without apparent phenotypic effect were re-investigated with non-isotopic in situ hybridization methods. Active nucleolus organizer regions were seen in the distal long arm region of all Yqs chromosomes studied and in situ hybridization with the probe D15Z1 showed that, in all three families, the Yqs was the result of a 15p;Yq translocation. In one case, an additional focus of D15Z1 hybridization was seen on 21p.
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Affiliation(s)
- T A Wilkinson
- Wessex Regional Genetics Laboratory, Salisbury District Hospital, Odstock, UK
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