title: The yeast STM1 gene encodes a purine motif triple helical DNA-binding protein.
abstract: The formation of triple helical DNA has been evoked in several cellular processes including transcription, replication, and recombination. Using conventional and affinity chromatography, we purified from Saccharomyces cerevisiae whole-cell extract a 35-kDa protein that avidly and specifically bound a purine motif triplex (with a K(d) of 61 pM) but not a pyrimidine motif triplex or duplex DNA. Peptide microsequencing identified this protein as the product of the STM1 gene. Confirmation that Stm1p is a purine motif triplex-binding protein was obtained by electrophoretic mobility shift assays using either bacterially expressed, recombinant Stm1p or whole-cell extracts from stm1Delta yeast. Stm1p has previously been identified as G4p2, a G-quartet nucleic acid-binding protein. This suggests that some proteins actually recognize features shared by G4 DNA and purine motif triplexes, e.g. Hoogsteen hydrogen-bonded guanines. Genetically, the STM1 gene has been identified as a multicopy suppressor of mutations in several genes involved in mitosis (e.g. TOM1, MPT5, and POP2). A possible role for multiplex DNA and its binding proteins in mitosis is discussed.
authors.affiliation: Department of Cancer Biology, The University of Texas M.D. Anderson Cancer, Houston, Texas 77030, USA.
authors.forename: L D
authors.initials: LD
authors.lastname: Nelson
authors.forename: M
authors.initials: M
authors.lastname: Musso
authors.forename: M W
authors.initials: MW
authors.lastname: Van Dyke
mesh_terms: D001120:Arginine / Q000378:metabolism; D001667:Binding, Competitive; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics*; D004591:Electrophoresis, Polyacrylamide Gel; D039642:Eukaryotic Initiation Factors; D005656:Fungal Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D007700:Kinetics; D008239:Lysine / Q000378:metabolism; D008957:Models, Genetic; D010448:Peptide Initiation Factors; D011687:Purines / Q000378:metabolism; D012316:RNA Nucleotidyltransferases / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D011994:Recombinant Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins
chemical_list: D004268:DNA-Binding Proteins; D039642:Eukaryotic Initiation Factors; D005656:Fungal Proteins; D010448:Peptide Initiation Factors; D011687:Purines; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; C083432:TIF3 protein, S cerevisiae; C051802:triplex DNA; D004247:DNA; D001120:Arginine; D012316:RNA Nucleotidyltransferases; D008239:Lysine