title: The mouse mismatch repair protein, MSH3, is a nucleoplasmic protein that aggregates into denser nuclear bodies under conditions of stress.
abstract: The mismatch repair protein, MSH3, together with MSH2, forms the MutSβ heterodimer which recognizes and repairs base pair mismatches and larger insertion/deletion loops in DNA. Lack of specific antibodies against mouse MSH3 has hampered studies of its expression and localization. Mouse MSH3 is not immunogenic in normal mice. This problem was overcome by immunizing msh3-knockout mice and generating a panel of ten monoclonal antibodies, two of which localize MSH3 specifically in cultured mouse cells and bind to an epitope containing amino-acids 33-37. The panel also includes two antibodies that recognise both mouse and human MSH3 and bind to a conserved epitope containing amino-acids 187-194. The mouse MSH3-specific antibodies show that MSH3 is a nuclear protein with a finely-granular nucleoplasmic distribution, largely absent from areas of condensed heterochromatin. Specificity of the localization was demonstrated by absence of immunostaining in a cell line from the msh3-knockout mouse. Furthermore, we show for the first time that stress treatment of mouse cells with ethanol or hydrogen peroxide caused the re-distribution of MSH3 into nuclear bodies containing the proliferating cell nuclear antigen (PCNA), a known binding partner of MutSβ.
authors.affiliation: Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, Shropshire, SY10 7AG. UK. ian.holt@rjah.nhs.uk
authors.forename: Ian
authors.initials: I
authors.lastname: Holt
authors.forename: Le
authors.initials: L
authors.lastname: Thanh Lam
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Tomé
authors.forename: Derick G
authors.initials: DG
authors.lastname: Wansink
authors.forename: Hein
authors.initials: H
authors.lastname: Te Riele
authors.forename: Geneviève
authors.initials: G
authors.lastname: Gourdon
authors.forename: Glenn E
authors.initials: GE
authors.lastname: Morris
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D015153:Blotting, Western; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D018604:Epitope Mapping; D006367:HeLa Cells; D006801:Humans; D006825:Hybridomas; D006861:Hydrogen Peroxide / Q000494:pharmacology; D051379:Mice; D018345:Mice, Knockout; D000074081:MutS Homolog 3 Protein; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D011506:Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; C089762:Msh3 protein, mouse; D000074081:MutS Homolog 3 Protein; D018809:Proliferating Cell Nuclear Antigen; D011506:Proteins; D006861:Hydrogen Peroxide