In Vitro Synthesis of Short DNA Pieces by DNA Polymerase α from Mouse Myeloma

• Published in: Journal of biochemistry (Tokyo) Vol. 88; no. 6; pp. 1869 - 1877
• Main Authors: MATSUKAGE, Akio, NISHIZAWA, Miwako, TAKAHASHI, Taijo, HOZUMI, Tatsunobu
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.12.1980
• Subjects: Animals; Cattle; DNA - biosynthesis; DNA Polymerase I - metabolism; DNA Polymerase II - metabolism; DNA-Directed DNA Polymerase - metabolism; Mice; Mice, Inbred BALB C; Multiple Myeloma - enzymology; Neoplasms, Experimental - enzymology; Nucleic Acid Denaturation; Nucleic Acid Hybridization; RNA - metabolism; Templates, Genetic
• ISSN: 0021-924X
• DOI: 10.1093/oxfordjournals.jbchem.a133163

The DNA chain elongation mechanisms of mouse DNA polymerases α and β have been analyzed by using denatured DNA with a (dT)n block at the 3′-end as a template in combination with RNA ((rA)12-20- primer. The (rA) DNA product synthesized by DNA polymerase a was 3–5 s in size even after prolonged reaction; instead of a size increase, the number of 3–5 s molecules increased with the reaction time. The size of products was not affected by differences in 3H-labeled substrate (dATP or dTTP), enzyme amount, KCI concentration, or the length of 3′-(dT)n blocks. On the other hand, DNA polymerase β syn thesized long DNA products by a highly distributive reaction mechanism. 3–5 a DNA pieces synthesized by DNA polymerase a were not elongated any further by DNA polymerase a, but were converted into long DNA chains by DNA polymerase . The results imply that DNA polymerase α recognizes the size of the product DNA, and shuts off further elongation.