1
|
Jayaraj A, Thayer KM, Beveridge DL, Hingorani MM. Molecular dynamics of mismatch detection-How MutS uses indirect readout to find errors in DNA. Biophys J 2023; 122:3031-3043. [PMID: 37329136 PMCID: PMC10432192 DOI: 10.1016/j.bpj.2023.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 04/30/2023] [Accepted: 06/12/2023] [Indexed: 06/18/2023] Open
Abstract
The mismatch repair protein MutS safeguards genomic integrity by finding and initiating repair of basepairing errors in DNA. Single-molecule studies show MutS diffusing on DNA, presumably scanning for mispaired/unpaired bases, and crystal structures show a characteristic "mismatch-recognition" complex with DNA enclosed within MutS and kinked at the site of error. But how MutS goes from scanning thousands of Watson-Crick basepairs to recognizing rare mismatches remains unanswered, largely because atomic-resolution data on the search process are lacking. Here, 10 μs all-atom molecular dynamics simulations of Thermus aquaticus MutS bound to homoduplex DNA and T-bulge DNA illuminate the structural dynamics underlying the search mechanism. MutS-DNA interactions constitute a multistep mechanism to check DNA over two helical turns for its 1) shape, through contacts with the sugar-phosphate backbone, 2) conformational flexibility, through bending/unbending engineered by large-scale motions of the clamp domain, and 3) local deformability, through basepair destabilizing contacts. Thus, MutS can localize a potential target by indirect readout due to lower energetic costs of bending mismatched DNA and identify a site that distorts easily due to weaker base stacking and pairing as a mismatch. The MutS signature Phe-X-Glu motif can then lock in the mismatch-recognition complex to initiate repair.
Collapse
Affiliation(s)
- Abhilash Jayaraj
- Chemistry Department, Wesleyan University, Middletown, Connecticut.
| | - Kelly M Thayer
- Chemistry Department, Wesleyan University, Middletown, Connecticut
| | | | - Manju M Hingorani
- Molecular Biology and Biochemistry Department, Wesleyan University, Middletown, Connecticut.
| |
Collapse
|
2
|
Fan X, Bai Q, Shi C, Xiao Y, Wang X. External quality assessment for the molecular detection of microsatellite instability in China, 2021-2022. Expert Rev Mol Diagn 2023; 23:1037-1043. [PMID: 37682059 DOI: 10.1080/14737159.2023.2257133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 08/14/2023] [Accepted: 08/27/2023] [Indexed: 09/09/2023]
Abstract
BACKGROUND Microsatellite instability (MSI) analysis of tumors informs Lynch syndrome testing, therapeutic choice, and prognosis. The status of MSI is mainly detected by polymerase chain reaction coupled with capillary electrophoresis. However, there are various assays with different detection loci and the obtained results may vary. The objective of this study was to evaluate the concordance among different assays and the performance among different laboratories. METHODS External quality assessment (EQA) for the detection of MSI was performed in 2021 and 2022. Each sample panel consisted of five samples, including microsatellite-stable and MSI tumor tissues. The sample panels were coded at random, and the returned results were compared and scored. RESULTS The fully validated sample panels showed appropriate applicability with commercially available assays. There were eight false-negative results in 2021 and five false results (two false-positives and three false-negatives) in 2022. Among the participating laboratories, in 2021, 20 (74.07%) provided completely correct results; in 2022, 38 (92.68%) obtained an optimal score. CONCLUSION The molecular detection of MSI in China exhibited an improvement in a 2-year EQA study. Participation in EQA program is an efficient way of assessing the performance of laboratories and improving their ability.
Collapse
Affiliation(s)
- Xiaoyu Fan
- Department of Molecular Biology, Shanghai Center for Clinical Laboratory, Shanghai, P.R. China
| | - Qianming Bai
- Department of Pathology, Fudan University Shanghai Cancer Center, Shanghai, P.R. China
| | - Chunli Shi
- Department of Molecular Biology, Shanghai Center for Clinical Laboratory, Shanghai, P.R. China
| | - Yanqun Xiao
- Department of Molecular Biology, Shanghai Center for Clinical Laboratory, Shanghai, P.R. China
| | - Xueliang Wang
- Department of Molecular Biology, Shanghai Center for Clinical Laboratory, Shanghai, P.R. China
- Department of Molecular Diagnostic Innovation Technology, Shanghai Academy of Experimental Medicine, Shanghai, P.R. China
| |
Collapse
|
3
|
Parente P, Grillo F, Vanoli A, Macciomei MC, Ambrosio MR, Scibetta N, Filippi E, Cataldo I, Baron L, Ingravallo G, Cazzato G, Melocchi L, Liserre B, Giordano C, Arborea G, Pilozzi E, Scapinello A, Aquilano MC, Gafà R, Battista S, Dal Santo L, Campora M, Carbone FG, Sartori C, Lazzi S, Hanspeter E, Angerilli V, Mastracci L, Fassan M. The Day-To-Day Practice of MMR and MSI Assessment in Colorectal Adenocarcinoma: What We Know and What We Still Need to Explore. Dig Dis 2023; 41:746-756. [PMID: 37231848 DOI: 10.1159/000531003] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 05/03/2023] [Indexed: 05/27/2023]
Abstract
BACKGROUND The DNA mismatch repair (MMR) system is a highly preserved protein complex recognizing short insertions, short deletions, and single base mismatches during DNA replication and recombination. MMR protein status is identified using immunohistochemistry. Deficit in one or more MMR proteins, configuring deficient MMR status (dMMR), leads to frameshift mutations particularly clustered in microsatellite repeats. Thus, microsatellite instability (MSI) is the epiphenomenon of dMMR. In colorectal cancer (CRC), MMR/MSI status is a biomarker with prognostic and predictive value of resistance to 5-fluorouracil and response to immune checkpoint inhibitor therapy. SUMMARY In this Review, we describe the challenges the practicing pathologist may face in relation to the assessment of MMR/MSI status and any open issues which still need to be addressed, focusing on pre-analytic issues, pitfalls in the interpretation, and technical aspects of the different assays. KEY MESSAGES The current methods of detecting dMMR/MSI status have been optimized for CRCs, and whether these techniques can be applied to all tumor and specimen types is still not fully understood. Following the Food and Drug Administration (FDA), tissue/site agnostic drug approval of pembrolizumab for advanced/metastatic MSI tumors, MMR/MSI status in gastrointestinal tract is a common request from the oncologist. In this setting, several issues still need to be addressed, including criteria for sample adequacy.
Collapse
Affiliation(s)
- Paola Parente
- Unit of Pathology, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Federica Grillo
- Anatomic Pathology, Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy
- Pathology Unit, Ospedale Policlinico San Martino IRCCS, Genoa, Italy
| | - Alessandro Vanoli
- Anatomic Pathology Unit, Department of Molecular Medicine, University of Pavia and Fondazione IRCCS San Matteo Hospital, Pavia, Italy
| | | | | | - Nunzia Scibetta
- UOC Anatomia Patologica ARNAS Ospedali Civico e G. Di Gristina, Palermo, Italy
| | | | - Ivana Cataldo
- Surgical Pathology Section University and Hospital Trust of Treviso, Treviso, Italy
| | - Luigi Baron
- Surgical Pathology Unit ASL Napoli 3 Sud, Ospedale S. Leonardo, Naples, Italy
| | - Giuseppe Ingravallo
- Section of Pathology, Department of Precision and Regenerative Medicine and Ionian Area, University of Bari "Aldo Moro", Bari, Italy
| | - Gerardo Cazzato
- Section of Pathology, Department of Precision and Regenerative Medicine and Ionian Area, University of Bari "Aldo Moro", Bari, Italy
| | - Laura Melocchi
- Unit of Pathology, Department of Oncology, Fondazione Poliambulanza Hospital Institute, Brescia, Italy
| | - Barbara Liserre
- Unit of Pathology, Department of Oncology, Fondazione Poliambulanza Hospital Institute, Brescia, Italy
| | - Carla Giordano
- Pathology Unit, Università La Sapienza; Policlinico Umberto I, Rome, Italy
| | - Graziana Arborea
- Department of Pathology, National Institute of Gastroenterology IRCCS "S. de Bellis", Castellana Grotte, Italy
| | - Emanuela Pilozzi
- Department of Clinical and Molecular Medicine, "Sapienza" University of Rome, Rome, Italy
| | | | - Maria Costanza Aquilano
- Department of Hematology, Oncology and Molecular Medicine, ASST Grande Ospedale Metropolitano/Niguarda, Milan, Italy
| | - Roberta Gafà
- Anatomic Pathology Unit, University Hospital of Ferrara, Ferrara, Italy
| | - Serena Battista
- Pathology Department, S. Maria della Misericordia Hospital, Udine, Italy
| | - Luca Dal Santo
- Department of Pathology, Ospedale dell'Angelo, Venice, Italy
| | - Michela Campora
- U.O.M. Anatomia e Istologia Patologica e Citodiagnostica Ospedale S. Chiara, Trento, Italy
| | | | - Chiara Sartori
- U.O.M. Anatomia e Istologia Patologica e Citodiagnostica Ospedale S. Chiara, Trento, Italy
| | - Stefano Lazzi
- Department of Medical Biotechnology, Section of Pathology, University of Siena, Siena, Italy
| | - Ester Hanspeter
- Department of Pathology, Provincial Hospital of Bolzano (SABES-ASDAA), Bolzano-Bozen, Italy
| | - Valentina Angerilli
- Surgical Pathology Unit, Department of Medicine (DIMED), University of Padua, Padua, Italy
| | - Luca Mastracci
- Anatomic Pathology, Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy
- Pathology Unit, Ospedale Policlinico San Martino IRCCS, Genoa, Italy
| | - Matteo Fassan
- Veneto Institute of Oncology, IOV-IRCCS, Padua, Italy
- Surgical Pathology Unit, Department of Medicine (DIMED), University of Padua, Padua, Italy
| |
Collapse
|
4
|
Inoue K, Takada S, Terakawa T. Coarse-grained molecular dynamics simulations of base-pair mismatch recognition protein MutS sliding along DNA. Biophys Physicobiol 2022; 19:1-16. [PMID: 35797408 PMCID: PMC9173861 DOI: 10.2142/biophysico.bppb-v19.0015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 04/12/2022] [Indexed: 12/01/2022] Open
Abstract
DNA mismatches are frequently generated by various intrinsic and extrinsic factors including DNA replication errors, oxygen species, ultraviolet, and ionizing radiation. These mismatches should be corrected by the mismatches repair (MMR) pathway to maintain genome integrity. In the Escherichia coli (E. coli) MMR pathway, MutS searches and recognizes a base-pair mismatch from millions of base-pairs. Once recognized, ADP bound to MutS is exchanged with ATP, which induces a conformational change in MutS. Previous single-molecule fluorescence microscopy studies have suggested that ADP-bound MutS temporarily slides along double-stranded DNA in a rotation-coupled manner to search a base-pair mismatch and so does ATP-bound MutS in a rotation-uncoupled manner. However, the detailed structural dynamics of the sliding remains unclear. In this study, we performed coarse-grained molecular dynamics simulations of the E. coli MutS bound on DNA in three different conformations: ADP-bound (MutSADP), ATP-bound open clamp (MutSOpenATP), and ATP-bound closed clamp (MutSClosedATP) conformations. In the simulations, we observed conformation-dependent diffusion of MutS along DNA. MutSADP and MutSClosedATP diffused along DNA in a rotation-coupled manner with rare and frequent groove-crossing events, respectively. In the groove-crossing events, MutS overcame an edge of a groove and temporarily diffused in a rotation-uncoupled manner. It was also indicated that mismatch searches by MutSOpenATP is inefficient in terms of mismatch checking even though it diffuses along DNA and reaches unchecked regions more rapidly than MutSADP.
Collapse
Affiliation(s)
- Keisuke Inoue
- Department of Biophysics, Graduate School of Science, Kyoto University
| | - Shoji Takada
- Department of Biophysics, Graduate School of Science, Kyoto University
| | - Tsuyoshi Terakawa
- Department of Biophysics, Graduate School of Science, Kyoto University
| |
Collapse
|
5
|
Abstract
DNA repair is an important component of genome integrity and organisms with reduced repair capabilities tend to accumulate mutations at elevated rates. Microsporidia are intracellular parasites exhibiting high levels of genetic divergence postulated to originate from the lack of several proteins, including the heterotrimeric Rad9–Rad1–Hus1 DNA repair clamp. Microsporidian species from the Encephalitozoonidae have undergone severe streamlining with small genomes coding for about 2,000 proteins. The highly divergent sequences found in Microsporidia render functional inferences difficult such that roughly half of these 2,000 proteins have no known function. Using a structural homology-based annotation approach combining protein structure prediction and tridimensional similarity searches, we found that the Rad9–Rad1–Hus1 DNA clamp is present in Microsporidia, together with many other components of the DNA repair machinery previously thought to be missing from these organisms. Altogether, our results indicate that the DNA repair machinery is present and likely functional in Microsporidia.
Collapse
|
6
|
Bigman LS, Greenblatt HM, Levy Y. What Are the Molecular Requirements for Protein Sliding along DNA? J Phys Chem B 2021; 125:3119-3131. [PMID: 33754737 PMCID: PMC8041311 DOI: 10.1021/acs.jpcb.1c00757] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
![]()
DNA-binding proteins rely on linear
diffusion along the longitudinal
DNA axis, supported by their nonspecific electrostatic affinity for
DNA, to search for their target recognition sites. One may therefore
expect that the ability to engage in linear diffusion along DNA is
universal to all DNA-binding proteins, with the detailed biophysical
characteristics of that diffusion differing between proteins depending
on their structures and functions. One key question is whether the
linear diffusion mechanism is defined by translation coupled with
rotation, a mechanism that is often termed sliding. We conduct coarse-grained
and atomistic molecular dynamics simulations to investigate the minimal
requirements for protein sliding along DNA. We show that coupling,
while widespread, is not universal. DNA-binding proteins that slide
along DNA transition to uncoupled translation–rotation (i.e.,
hopping) at higher salt concentrations. Furthermore, and consistently
with experimental reports, we find that the sliding mechanism is the
less dominant mechanism for some DNA-binding proteins, even at low
salt concentrations. In particular, the toroidal PCNA protein is shown
to follow the hopping rather than the sliding mechanism.
Collapse
Affiliation(s)
- Lavi S Bigman
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Harry M Greenblatt
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yaakov Levy
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| |
Collapse
|