DNA damage can occur naturally or through environmental factors, leading to mutations in DNA replication and genomic instability in cells. Normally, natural d-nucleotides were selected by DNA polymerases. The template l-thymidine (l-T) has been shown to be bypassed by several types of DNA polymerases. However, DNA replication fidelity of nucleotide incorporation opposite l-thymidine in vivo remains unknown. Here, we constructed plasmids containing a restriction enzyme (PstI) recognition site in which the l-T lesion was site-specifically located within the PstI recognition sequence (CTGCAG). Further, we assessed the efficiencies of nucleotide incorporation opposite the l-T site and l-T lesion bypass replication in vitro and in vivo. We found that recombinants containing the l-T lesion site inhibited DNA replication. In addition, A was incorporated opposite the l-T lesion by routine PCR assay, whereas preference for nucleotide incorporation opposite the l-T site was A (13%), T (22%), C (46%), and G (19%), and no nucleotide insertion and deletions were detected in E. coli cells. In particular, a novel restriction enzyme-mediated method for detection of the mutagenic properties of DNA lesion was established, which allows us to readily detect restriction–digestion of the l-T-bearing plasmids. The study provided significant insight into how mirror-image nucleosides perturb the fidelity of DNA replication in vivo and whether they elicit mutagenic effects, which may help to understand both how DNA damage interferes with the flow of genetic information during DNA replication and development of diseases caused by gene mutation.

An early step in the initiation of polyomavirus DNA replication is viral large-T-antigen-mediated unwinding of the origin. We report that components of the AP1 transcription factor, Fos and Jun, interact with T antigen in vitro to enhance unwinding of the viral origin. This provides a biochemical basis for the capacity of AP1 to activate viral DNA replication in vivo.

Metrics & MoreArticle RecommendationsI n the original article, the description of the incorporation frequency opposite L-T was not completely correct and should be corrected as follows: In the abstract, "nucleotide incorporation opposite the L-T site was" (p. 2276, line 14) should be corrected to "transition from L-T to". Similarly, "that nucleotide incorporated opposite the L-T site was" in the third section of the Results (p. 2282, line 49, the left column) should be corrected to "the transition from L-T to". In the Discussion, "misincorporation of" (p. 2282, line 46, the right column) needs to be changed to "transition from L-T to" and "and", "incorporation of", and "opposite of L-T" should be deleted. In addition, "L-T → A, L-T → G, and L-T → C" (p. 2280, line 4, the left column) was mistakenly described in the first section of the Results based in Figure 3 and should be corrected to "L-T → G, L-T → C, and L-T → A".These corrections do not change the conclusions of this manuscript. We apologize for the errors and any inconvenience that they may have caused.

Enantiomers of chiral substances typically have distinct biological activities, thus, the explorations of biochemical processes at the enantiomeric level has very high significance. This study investigated DNA polymerase-catalyzed reaction modulated by various types of chiral cobalt complexes. The experimental data showed that polymerase reactions were inhibited or accelerated in the presence of KMore importantly, the stereocontrol of bioreactivity was found to be different for the enantiomers, which was reflected in their ability to bind to the polymerase reaction system. The docking simulation illustrated that the acceleration or inhibition of polymerase reaction could be correlated with diverse electrostatic energy induced by the attached metal chelates, whereas the different stereocontrol of bioreactivity for the enantiomers was attributed to a discrepancy of Van der Waals interactions between the enantiomer and polymerase catalytic sites.