Origin DNA melting and unwinding in DNA replication

Common determinants in DNA melting and helicase-catalysed DNA unwinding by papillomavirus replication protein E1

E1 and T-antigen of the tumour viruses bovine papillomavirus (BPV-1) and Simian virus 40 (SV40) are the initiator proteins that recognize and melt their respective origins of replication in the initial phase of DNA replication. These proteins then assemble into processive hexameric helicases upon the single-stranded DNA that they create. In T-antigen, a characteristic loop and hairpin structure...

Active DNA unwinding dynamics during processive DNA replication.

Duplication of double-stranded DNA (dsDNA) requires a fine-tuned coordination between the DNA replication and unwinding reactions. Using optical tweezers, we probed the coupling dynamics between these two activities when they are simultaneously carried out by individual Phi29 DNA polymerase molecules replicating a dsDNA hairpin. We used the wild-type and an unwinding deficient polymerase varian...

The inefficient replication origin from yeast ribosomal DNA is naturally impaired in the ARS consensus sequence and in DNA unwinding.

Ribosomal DNA (rDNA) replication origins of Saccharomyces cerevisiae are known to function inefficiently, both in the context of the tandem rDNA repeats in the chromosome and as single copy autonomously replicating sequences (ARSs) in plasmids. Here we examined components of the rDNA ARS that might contribute to inefficient extrachromosomal replication. Like the efficient H4 ARS, the rDNA ARS r...

Origin and Role of DNA Damage in Varicocele

Oligomeric initiator protein-mediated DNA looping negatively regulates plasmid replication in vitro by preventing origin melting.

Although DNA looping between the initiator binding sites (iterons) of the replication origin (ori) of a plasmid and the iterons located in a cis-acting control sequence called inc has been postulated to promote negative control of plasmid DNA replication, not only was definitive evidence for such looping lacking, but also the detailed molecular mechanism of this control had not been elucidated....