What causes a single strand break?

What causes a single strand break?

Forcing cells into the radiosensitive phase of the cell cycle or increasing the presence of oxygen prior to irradiating can enhance cell kill. Radiation induces single-strand DNA breaks and double-strand breaks (dsDNA breaks) which are repaired by nonhomologous recombination and homologous recombination.

What is a single strand DNA break?

DNA single-strand breaks (SSBs) are discontinuities in one strand of the DNA double helix, and are often associated with damaged or mismatched 5′- and/or 3′-termini at the sites of SSBs [1].

What is single strand break repair?

Abstract. DNA single-strand break repair (SSBR) is critical for the survival and genetic stability of mammalian cells. Three papers have recently associated mutations in putative human SSBR genes with hereditary spinocerebellar ataxia. The emerging links between SSBR and neurodegenerative disorders are discussed.

What is single strand break and double strand break?

Single strand break is DNA damage that occurs in one strand out of the double strands hence, only one strand defects in single strand break DNA damage. Double strand break is DNA damage that occurs in both strands hence, the chemical structure of both strands is altered in the double strand damage.

Does UV cause double-strand breaks?

UV-C irradiation also causes the production of reactive oxygen species, which can result in DNA double-strand breaks (DSBs) (6, 44).

What is a double-strand break?

The DNA double-strand break (DSB) is the principle cytotoxic lesion for ionizing radiation and radio-mimetic chemicals but can also be caused by mechanical stress on chromosomes or when a replicative DNA polymerase encounters a DNA single-strand break or other type of DNA lesion.

What is single strand damage?

Of the different types of DNA damage that arise in cells, single-strand breaks (SSBs) are the most common, arising at a frequency of tens of thousands per cell per day from direct attack by intracellular metabolites and from spontaneous DNA decay.

What does single-stranded mean?

Biology definition: Single-stranded DNA is a DNA molecule that consists of only a single strand contrary to the typical two strands of nucleotides in helical form.

What is double stranded DNA antibody?

Description. Anti-(double stranded)-DNA antibodies are highly specific markers of SLE and autoimmune (lupoid) hepatitis. Raised levels are found in 50-70% of patients with active, particularly untreated, SLE. Some patients with SLE (40-60%) however, never develop anti-DNA antibodies.

What causes double-strand breaks?

Double-strand breaks (DSBs) in DNA form as a result of exposure to exogenous agents such as radiation and certain chemicals, as well as through endogenous processes, including DNA replication and repair.

What does single stranded mean?

What are ssDNA viruses?

Abstract. Single-stranded (ss)DNA viruses are extremely widespread, infect diverse hosts from all three domains of life and include important pathogens. Most ssDNA viruses possess small genomes that replicate by the rolling-circle-like mechanism initiated by a distinct virus-encoded endonuclease.

Why is single-stranded unstable?

However, single-stranded DNA (ssDNA) is frequently exposed as a result of many cellular processes, including replication, transcription, and recombination. The exposed ssDNA is vulnerable to chemical attack and nucleolytic degradation; therefore, it must be properly protected to avoid mutations.