title: The carboxyl-terminal region common to lamins A and C contains a DNA binding domain.
abstract: Lamins A and C are intermediate filament proteins which polymerize into the nucleus to form the nuclear lamina network. The lamina is apposed to the inner nuclear membrane and functions in tethering chromatin to the nuclear envelope and in maintaining nuclear shape. We have recently characterized a globular domain that adopts an immunoglobulin fold in the carboxyl-terminal tail common to lamins A and C. Using an electrophoretic mobility shift assay (EMSA), we show that a peptide containing this domain interacts in vitro with DNA after dimerization through a disulfide bond, but does not interact with the core particle or the dinucleosome. The covalent dimer binds a 30-40 bp DNA fragment with a micromolar affinity and no sequence specificity. Using nuclear magnetic resonance (NMR) and an EMSA, we observed that two peptide regions participate in the DNA binding: the unstructured amino-terminal part containing the nuclear localization signal and a large positively charged region centered around amino acid R482 at the surface of the immunoglobulin-like domain. Mutations R482Q and -W, which are responsible for Dunnigan-type partial lipodystrophy, lower the affinity of the peptide for DNA. We conclude that the carboxyl-terminal end of lamins A and C binds DNA and suggest that alterations in lamin-DNA interactions may play a role in the pathophysiology of some lamin-linked diseases.
authors.affiliation: Département de Biologie Supramoléculaire et Cellulaire, Institut Jacques Monod-CNRS UMR 7592, Universités Paris 6/Paris 7, 2 place Jussieu, 75251 Paris cedex 05, France.
authors.forename: Vérène
authors.initials: V
authors.lastname: Stierlé
authors.forename: Joël
authors.initials: J
authors.lastname: Couprie
authors.forename: Cecilia
authors.initials: C
authors.lastname: Ostlund
authors.forename: Isabelle
authors.initials: I
authors.lastname: Krimm
authors.forename: Sophie
authors.initials: S
authors.lastname: Zinn-Justin
authors.forename: Paul
authors.initials: P
authors.lastname: Hossenlopp
authors.forename: Howard J
authors.initials: HJ
authors.lastname: Worman
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Courvalin
authors.forename: Isabelle
authors.initials: I
authors.lastname: Duband-Goulet
mesh_terms: D019943:Amino Acid Substitution; D001483:Base Sequence; D001665:Binding Sites; D001666:Binding Sites, Antibody; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D019281:Dimerization; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D006801:Humans; D034904:Lamin Type A / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D034921:Lamin Type B / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008060:Lipodystrophy / Q000235:genetics; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D013577:Syndrome
chemical_list: D034904:Lamin Type A; D034921:Lamin Type B; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D004247:DNA; D005982:Glutathione Transferase