An Activity from Mammalian Cells That Untwists Superhelical DNA—A Possible Swivel For DNA Replication

AUTOR(ES)

Champoux, James J.

RESUMO

Nuclei from secondary mouse-embryo cells contain an activity capable of untwisting closed-circular DNAs containing either negative or positive superhelical turns. The activity has no apparent effect on a closed-circular DNA containing no superhelical turns, and is not due to the combined action of an endonuclease and polynucleotide ligase. The enzyme apparently acts by introducing a single-strand nick into the DNA, forming a DNA-enzyme complex that allows the strands to rotate relative to the helix axis before reversing the reaction and sealing the break. The enzyme might possibly serve as a swivel during DNA replication.

Documentos Relacionados

• Variable region genes for the immunoglobulin framework are assembled from small segments of DNA—A hypothesis
• Mycobacterium smegmatis dnaA region and autonomous replication activity.
• Variation in DNA swivel enzyme activity during the mammalian cell cycle.
• The DNA-A Component of a Plant Geminivirus (Indian Mung Bean Yellow Mosaic Virus) Replicates in Budding Yeast Cells
• DnaA dependent replication of plasmid R1 occurs in the presence of point mutations that disrupt the dnaA box of oriR.