Characterization of nascent DNA fragments produced by excision of uracil residues in DNA.
AUTOR(ES)
Machida, Y
RESUMO
Nascent short DNA chains could result from repair of incorporated uracil residues or be intermediates in discontinuous replication. We have characterized short DNA chains having apyrimidinic/apurinic-sites at 5' ends, the expected intermediates of repair, to distinguish them from RNA-linked replication intermediates. We have synthesized model substrates for the repair products; d(pRib[32P]poly(T)) and d(Rib[32P]poly(T)). Alkaline hydrolysis of both substrates has produced [5'-32P]poly(dT). Nascent short DNA was prepared from an Escherichia coli sof (dut) mutant, in this strain fragments from excision repair of uracil residues accumulate. The products of alkaline treatment are hardly digested by spleen exonuclease which selectively degrades 5'-hydroxyl-terminated DNA. These two results show that alkaline hydrolysis of the uracil repair fragments produces 5'-phosphoryl-terminated DNA, whereas it is known that 5'-hydroxyl-terminated DNA is generated from RNA-linked DNA molecules. The two types of nascent fragments thus can be distinguished by the 5'-terminal structure produced by an alkaline hydrolysis.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=327473Documentos Relacionados
- Transient accumulation of Okazaki fragments as a result of uracil incorporation into nascent DNA.
- Generation of single-nucleotide repair patches following excision of uracil residues from DNA.
- Perturbations of enzymic uracil excision due to purine damage in DNA.
- Excision of uracil residues in DNA: mechanism of action of Escherichia coli and Micrococcus luteus uracil-DNA glycosylases.
- DNA base excision repair of uracil residues in reconstituted nucleosome core particles