What are DSBs in genetics?
DNA double strand breaks (DSB) are considered the most lethal form of DNA damage for eukaryotic cells. DSB can either be properly repaired, restoring genomic integrity, or misrepaired resulting in drastic consequences, such as cell death, genomic instability, and cancer.
What causes DSBs?
The genome of a cell is continuously damaged, which is inevitable because DNA damage often arises as a result of normal cellular processes. The result is double-strand breaks (DSBs) in the chromosome. A DSB can also be caused by environmental exposure to irradiation, other chemical agents, or ultraviolet light (UV).
What is DSB in biology?
Definition. A double-strand DNA break (DSB) occurs or arises when both strands of the DNA duplex are severed, often as the result of ionizing radiation.
How are DSBs detected?
The ATM kinase plays an early, pivotal role in the signaling process by detecting DSBs and relaying this information to numerous downstream transducer and effector proteins. Within minutes after DSBs occur, ATM undergoes inter-molecular autophosphorylation at Ser1981, which converts it to an active monomer.
What are double strand breaks DNA?
Abstract. 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 does synthetic lethality mean?
Listen to pronunciation. (sin-THEH-tik lee-THA-luh-tee) Describes a situation in which mutations (changes) in two genes together result in cell death, but a mutation in either gene alone does not.
What are the repair mechanism for double strand DNA breaks?
DNA double-strand breaks are repaired by means of two main mechanisms: nonhomologous end joining and homologous recombination (see Figure 1). Both mechanisms operate in all eukaryotic cells that have been examined but the relative contribution of each mechanism varies.
What is meant by the term heteroduplex DNA?
: a nucleic-acid molecule (such as DNA) composed of two chains with each derived from a different parent molecule.
Why is RNA a single-strand?
Unlike DNA, RNA in biological cells is predominantly a single-stranded molecule. This hydroxyl group make RNA less stable than DNA because it is more susceptible to hydrolysis. RNA contains the unmethylated form of the base thymine called uracil (U) (Figure 6), which gives the nucleotide uridine.
What is the other name of DSB repair pathway?
What is the other name of DSB repair pathway? Explanation: The major DSB repair pathway is also known as the RecBCD pathway. Homologous recombination in eukaryotic cells and the proteins are involved in this pathway.
What is the likely reason for DNA being double stranded?
The common theme of all the excision mechanisms is that DNA must be double stranded to provide a template for the repair. Separate from these, there are proteins involved in the direct reversal of damage (e.g., photoreactivation, O6 methylguanine DNA methyl transferase).