Preparation and isolation of covalently closed circular rDNA molecules from DNA of Xenopus laevis.

AUTOR(ES)

Polito, L C

RESUMO

We describe a method leading to the formation of closed circles of rDNA starting from total DNA of Xenopus laevis. Linear DNA molecules were digested with exonuclease 3 and self-annealed. Open circles were enriched and covalently closed by the simultaneous use of polynucleotide kinase, DNA polymerase and polynucleotide ligase. Closed circles of rDNA1 were shown to be alkali-resistant, to have higher density than linear molecules in cesium chloride density gradients containing ethydium bromide, and to have the sedimentation constant expected for a single repeat unit of rDNA comprehensive of its spacer.

Documentos Relacionados

• Isolation and characterization of calmodulin genes from Xenopus laevis.
• Mapping of the Xenopus laevis 5.8S rDNA by restriction and DNA sequencing.
• The external transcribed spacer and preceding region of Xenopus borealis rDNA: comparison with the corresponding region of Xenopus laevis rDNA.
• New Method for Large-Scale Preparation of Covalently Closed λ DNA Molecules
• Microscale method for rapid isolation of covalently closed circular plasmid DNA from group N streptococci.