Biomaterial Database

Isolation and characterization of a DNA primase from human mitochondria. 1985

T W Wong, and D A Clayton

A family of enzymatic activities isolated from human mitochondria is capable of initiating DNA replication on single-stranded templates. The principal enzymes include at least a primase and DNA polymerase gamma and require that rNTPs as well as dNTPs be present in the reaction mixture. Poly(dC) and poly(dT), as well as M13 phage DNA, are excellent templates for the primase activity. A single-stranded DNA containing the cloned origin of mitochondrial light-strand synthesis can be a more efficient template than M13 phage DNA alone. Primase and DNA polymerase activities were separated from each other by sedimentation in a glycerol density gradient. Using M13 phage DNA as template, these mitochondrial enzymes synthesize RNA primers that are 9 to 12 nucleotides in size and are covalently linked to nascent DNA. The formation of primers appears to be the rate-limiting step in the replication process. Replication of M13 DNA is sensitive to N-ethylmaleimide and dideoxynucleoside triphosphates, but insensitive to rifampicin, alpha-amanitin, and aphidicolin.

UI	MeSH Term	Description	Entries
D008928	Mitochondria	Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)	Mitochondrial Contraction,Mitochondrion,Contraction, Mitochondrial,Contractions, Mitochondrial,Mitochondrial Contractions
D009841	Oligonucleotides	Polymers made up of a few (2-20) nucleotides. In molecular genetics, they refer to a short sequence synthesized to match a region where a mutation is known to occur, and then used as a probe (OLIGONUCLEOTIDE PROBES). (Dorland, 28th ed)	Oligonucleotide
D004259	DNA-Directed DNA Polymerase	DNA-dependent DNA polymerases found in bacteria, animal and plant cells. During the replication process, these enzymes catalyze the addition of deoxyribonucleotide residues to the end of a DNA strand in the presence of DNA as template-primer. They also possess exonuclease activity and therefore function in DNA repair.	DNA Polymerase,DNA Polymerases,DNA-Dependent DNA Polymerases,DNA Polymerase N3,DNA Dependent DNA Polymerases,DNA Directed DNA Polymerase,DNA Polymerase, DNA-Directed,DNA Polymerases, DNA-Dependent,Polymerase N3, DNA,Polymerase, DNA,Polymerase, DNA-Directed DNA,Polymerases, DNA,Polymerases, DNA-Dependent 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
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D012316	RNA Nucleotidyltransferases	Enzymes that catalyze the template-directed incorporation of ribonucleotides into an RNA chain. EC 2.7.7.-.	Nucleotidyltransferases, RNA
D019915	DNA Primase	A single-stranded DNA-dependent RNA polymerase that functions to initiate, or prime, DNA synthesis by synthesizing oligoribonucleotide primers. EC 2.7.7.-.	Primase,Bacteriophage T7 Gene 4 Protein,DnaG (Primase),DnaG Gene Product,DnaG Protein,T7 DNA Primase-Helicase Protein,T7 DNA-Priming Protein,T7 gene-4 protein,DNA-Priming Protein, T7,Primase, DNA,Protein, T7 DNA-Priming,T7 DNA Primase Helicase Protein,T7 DNA Priming Protein,T7 gene 4 protein
D066298	In Vitro Techniques	Methods to study reactions or processes taking place in an artificial environment outside the living organism.	In Vitro Test,In Vitro Testing,In Vitro Tests,In Vitro as Topic,In Vitro,In Vitro Technique,In Vitro Testings,Technique, In Vitro,Techniques, In Vitro,Test, In Vitro,Testing, In Vitro,Testings, In Vitro,Tests, In Vitro,Vitro Testing, In