Translesion DNA synthesis (TLS) by specialized DNA polymerases (Pols) is a conserved mechanism for tolerating replication blocking DNA lesions. The actions of TLS Pols are managed in part by ring-shaped sliding clamp proteins. In addition to catalyzing TLS, altered expression of TLS Pols impedes cellular growth. The goal of this study was to define the relationship between the physiological fun...

in order to study adaptation ability of 15 commercial olive cultivars, this experiment was carried out using a randomized complete block design with three replication during the period from 2007 to 2009 in dry-warm climate of sar-pol-e-zehab dallaho olive station of kermanshah province. in this experiment, vegetative and reproductive traits were measured according to i.o.o.c. descriptors. flora...

Purified RNA polymerase II (pol II) from the yeast Saccharomyces cerevisiae pauses without releasing at many locations during in vitro transcription. Pausing can be induced by intrinsic DNA sequence as well as by specific DNA bound proteins such as the RNA pol I termination factor, Reb1p, or lac repressor. Addition of rho termination factor from E. coli induces RNA pol II to release at all of t...

Reaction of bifunctional electrophiles with DNA in the presence of peptides can result in DNA-peptide cross-links. In particular, the linkage can be formed in the major groove of DNA via the exocyclic amino group of adenine (N⁶-dA). We previously demonstrated that an A family human polymerase, Pol ν, can efficiently and accurately synthesize DNA past N⁶-dA-linked peptides. Based on these result...

The E. coli umuDC gene products participate in two temporally distinct roles: UmuD2C acts in a DNA damage checkpoint control, while UmuD'2C, also known as DNA polymerase V (Pol V), catalyzes replication past DNA lesions via a process termed translesion DNA synthesis. These different roles of the umuDC gene products are managed in part by the dnaN-encoded β sliding clamp protein. Co-overexpressi...

Irradiation of organisms with UV light produces genotoxic and mutagenic lesions in DNA. Replication through these lesions (translesion DNA synthesis, TSL) in Escherichia coli requires polymerase V (Pol V) and polymerase III (Pol III) holoenzyme. However, some evidence indicates that in the absence of Pol V, and with Pol III inactivated in its proofreading activity by the mutD5 mutation, efficie...

Escherichia coli DNA polymerase I (pol I), discovered by Arthur Kornberg and colleagues in 1956. Thirteen years later, Paula de Lucia and John Cairns, at Stony Brook, New York, isolated an E. coli mutant, polA (its designation being a play on de Lucia’s first name, as proposed to Cairns by Julian Gross) that seemed to have less than 1% of the normal pol I activity. From this strain, a new DNA-p...

W e used to think cells could get by with just a few DNA polymerases. One processive polymerase in Escherichia coli [polymerase III (Pol III)] was needed to make the long trip around the genome, and another one (Pol I) was needed to replace Okazaki fragment primers or damaged nucleotides. This view changed radically after 2 seminal studies by Nelson, Lawrence, and Hinkle (1, 2) in which 2 yeast...

Reactive oxygen species generate many lesions in DNA, including R and S diastereomers of 8,5'-cyclo-2'-deoxyadenosine (cdA) and 8,5'-cyclo-2'-deoxyguanosine (cdG). Herein, the result of replication of a plasmid containing S-cdA in Escherichia coli is reported. S-cdA was found mutagenic and highly genotoxic. Viability and mutagenicity of the S-cdA construct were dependent on functional pol V, bu...

Pol I is the most abundant polymerase in E. coli and plays an important role in short patch repair. In accord with this role in the cell, the purified polymerase exhibits low processivity and high fidelity in vitro. Pol I is also the polymerase responsible for leader strand synthesis during ColE1 plasmid replication. In a previous publication, we described the generation of a highly error-prone...