Topoisomerases are ubiquitous proteins found in all three domains of life. They change the topology of DNA via transient breaks on either one or two of the DNA strands to allow passage of another single or double DNA strand through the break. Topoisomerases are classified into two types: type I enzymes cleave one DNA strand and pass either one or two DNA strands through the break before reseali...

Computer analyses of DNA sequencing data obtained using various restriction fragments of pBR 322 DNA indicate that a trinucleotide sequence (-Pyr-G-C-) is the most preferred site for cleavage by the antitumor antibiotic bleomycin A2. Talisomycin A, a structurally related bleomycin analog, cleaved at the sequences -G-T/A- most preferentially. However, the presence of a pyrimidine at the 5' side ...

Third-generation DNA sequencing has enabled of long, unamplified fragments with minimal steps. Direct ssDNA or RNA gives valuable insights like base-level modifications, phosphoramidite synthesis yield estimates and strand quality analysis, without the need to add complimentary strand. single-stranded nucleic acid species is challenging as they are non-compatible double-stranded adapters...

Background: ˝Radioadaptive Response˝ is well-documented phenomenon appeared in low dose ionizing radiation received in vitro and in vivo. Occupational exposure has always been a great concern for radiation workers therefore this study was performed to study radioadaptive response in terms of residual DNA double strand breaks as an endpoint in peripheral blood leukocytes of occupationally expose...

DNA double-strand breaks (DSBs) can be repaired by homologous recombination (HR), which can involve Holliday junction (HJ) intermediates that are ultimately resolved by nucleolytic enzymes. An N-terminal fragment of human GEN1 has recently been shown to act as a Holliday junction resolvase, but little is known about the role of GEN-1 in vivo. Holliday junction resolution signifies the completio...

The repair of double-strand breaks in mammalian cells is carried out by two pathways: homologous recombination and nonhomologous end joining. The factors that regulate the mechanism through which a specific repair pathway is activated are still not clearly defined. To study whether the complexity of the double-strand break ends is a factor that determines the choice of the repair pathway, we ex...

Fluorescence from a single DNA molecule passing through a laser beam is proportional to the size (contour length) of the molecule, and molecules of different sizes can be counted with equal efficiencies. Single-molecule fluorescence can thus determine the average length of the molecules in a sample and hence the frequency of double-strand breaks induced by various treatments. Ionizing radiation...

background: ˝radioadaptive response˝ is well-documented phenomenon appeared in low dose ionizing radiation received in vitro and in vivo. occupational exposure has always been a great concern for radiation workers therefore this study was performed to study radioadaptive response in terms of residual dna double strand breaks as an endpoint in peripheral blood leukocytes of occupationally expose...

DNA termini at double-strand breaks are often chemically heterogeneous and require processing before initiation of repair. In a recent report, we demonstrated that CtIP and the MRE11-RAD50-NBS1 (MRN) nuclease complex cooperate with BRCA1 to specifically repair topoisomerase II-DNA adducted breaks. In contrast, BRCA1 is dispensable for repair of restriction endonuclease-generated double-strand b...