Regions of Single-Stranded DNA in the Growing Points of Replicating Bacteriophage T7 Chromosomes*

AUTOR(ES)

Wolfson, John

RESUMO

In partially replicated T7 chromosomes, the points where parental strands are separating and new DNA is being synthesized can be seen in the electron microscope to contain regions of single-stranded template DNA. The single-stranded regions are located on only one of the two daughter arms of the replicating chromosome. Inman and Schnös observed such single-stranded regions in 50% of the growing points of replicating lambda DNA, and, as reported in this paper, we find them in about 85% of the growing points of T7 DNA. Both studies support the conclusion that DNA synthesis involves the direct elongation of one daughter strand in the growing point. Evidently, this elongation is accompanied by the unwinding of the parental double helix to expose a region of single-stranded DNA which is then converted to the duplex state by a discontinuous mechanism involving the synthesis of DNA fragments.

Documentos Relacionados

• The Cys4 zinc finger of bacteriophage T7 primase in sequence-specific single-stranded DNA recognition
• Single-stranded DNA binding protein and DNA helicase of bacteriophage T7 mediate homologous DNA strand exchange.
• Structure of the gene 2.5 protein, a single-stranded DNA binding protein encoded by bacteriophage T7
• C-terminal Phenylalanine of Bacteriophage T7 Single-stranded DNA-binding Protein Is Essential for Strand Displacement Synthesis by T7 DNA Polymerase at a Nick in DNA*
• Bacteriophage T7 helicase/primase proteins form rings around single-stranded DNA that suggest a general structure for hexameric helicases.