Biomaterial Database

Termination within oligo(dT) tracts in template DNA by DNA polymerase gamma occurs with formation of a DNA triplex structure and is relieved by mitochondrial single-stranded DNA-binding protein. 1996

V S Mikhailov, and D F Bogenhagen

Department of Pharmacological Sciences, State University of New York at Stony Brook, Stony Brook, New York 11794, USA.

Xenopus laevis DNA polymerase gamma (pol gamma) exhibits low activity on a poly(dT)-oligo(dA) primer-template. We prepared a single-stranded phagemid template containing a dT41 sequence to test the ability of pol gamma to extend a primer through a defined oligo(dT) tract. pol gamma terminates in the center of this dT41 sequence. This replication arrest is abrogated by addition of single-stranded DNA-binding protein or by substitution of 7-deaza-dATP for dATP. These features are consistent with the formation of a T.A*T DNA triplex involving the primer stem. Replication arrest occurs under conditions that permit highly processive DNA synthesis by pol gamma. A similar replication arrest occurs for T7 DNA polymerase, which is also a highly processive DNA polymerase. These results suggest the possibility that DNA triplex formation can occur prior to dissociation of DNA polymerase. Primers with 3'-oligo(dA) termini annealed to a template with a longer oligo(dT) tract are not efficiently extended by pol gamma unless single-stranded DNA-binding protein is added. Thus, one of the functions of single-stranded DNA-binding protein in mtDNA maintenance may be to enable pol gamma to successfully replicate through dT-rich sequences.

UI	MeSH Term	Description	Entries
D009690	Nucleic Acid Conformation	The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.	DNA Conformation,RNA Conformation,Conformation, DNA,Conformation, Nucleic Acid,Conformation, RNA,Conformations, DNA,Conformations, Nucleic Acid,Conformations, RNA,DNA Conformations,Nucleic Acid Conformations,RNA Conformations
D009838	Oligodeoxyribonucleotides	A group of deoxyribonucleotides (up to 12) in which the phosphate residues of each deoxyribonucleotide act as bridges in forming diester linkages between the deoxyribose moieties.	Oligodeoxynucleotide,Oligodeoxyribonucleotide,Oligodeoxynucleotides
D004247	DNA	A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).	DNA, Double-Stranded,Deoxyribonucleic Acid,ds-DNA,DNA, Double Stranded,Double-Stranded DNA,ds DNA
D004258	DNA Polymerase III	A DNA-dependent DNA polymerase characterized in E. coli and other lower organisms but may be present in higher organisms. Use also for a more complex form of DNA polymerase III designated as DNA polymerase III* or pol III* which is 15 times more active biologically than DNA polymerase I in the synthesis of DNA. This polymerase has both 3'-5' and 5'-3' exonuclease activities, is inhibited by sulfhydryl reagents, and has the same template-primer dependence as pol II.	DNA Polymerase delta,DNA-Dependent DNA Polymerase III,DNA Pol III,DNA Dependent DNA Polymerase III,Polymerase III, DNA,Polymerase delta, DNA
D004261	DNA Replication	The process by which a DNA molecule is duplicated.	Autonomous Replication,Replication, Autonomous,Autonomous Replications,DNA Replications,Replication, DNA,Replications, Autonomous,Replications, DNA
D004268	DNA-Binding Proteins	Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.	DNA Helix Destabilizing Proteins,DNA-Binding Protein,Single-Stranded DNA Binding Proteins,DNA Binding Protein,DNA Single-Stranded Binding Protein,SS DNA BP,Single-Stranded DNA-Binding Protein,Binding Protein, DNA,DNA Binding Proteins,DNA Single Stranded Binding Protein,DNA-Binding Protein, Single-Stranded,Protein, DNA-Binding,Single Stranded DNA Binding Protein,Single Stranded DNA Binding Proteins
D004277	DNA, Single-Stranded	A single chain of deoxyribonucleotides that occurs in some bacteria and viruses. It usually exists as a covalently closed circle.	Single-Stranded DNA,DNA, Single Stranded,Single Stranded DNA
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D001482	Base Composition	The relative amounts of the PURINES and PYRIMIDINES in a nucleic acid.	Base Ratio,G+C Composition,Guanine + Cytosine Composition,G+C Content,GC Composition,GC Content,Guanine + Cytosine Content,Base Compositions,Base Ratios,Composition, Base,Composition, G+C,Composition, GC,Compositions, Base,Compositions, G+C,Compositions, GC,Content, G+C,Content, GC,Contents, G+C,Contents, GC,G+C Compositions,G+C Contents,GC Compositions,GC Contents,Ratio, Base,Ratios, Base
D013698	Templates, Genetic	Macromolecular molds for the synthesis of complementary macromolecules, as in DNA REPLICATION; GENETIC TRANSCRIPTION of DNA to RNA, and GENETIC TRANSLATION of RNA into POLYPEPTIDES.	Genetic Template,Genetic Templates,Template, Genetic