thymine dimer

(redirected from Thymine dimers)

thy·mine di·mer

a product of ultraviolet irradiation of thymine (free in ice or bound in nucleic acids) in which two thymine residues become linked by formation of a cyclobutane ring involving both C-5's and both C-6's at the expense of the two double bonds; several stereoisomeric forms are possible.

thymine dimer

a pair of adjacent THYMINE residues in a single POLYNUCLEOTIDE CHAIN that have become chemically bonded, usually by the action of ULTRAVIOLET LIGHT. The lesion can inhibit DNA replication unless repaired. However, the processes responsible for repairing the lesion sometimes make errors, in turn creating MUTATIONS. see XERODERMA PIGMENTOSUM.
References in periodicals archive ?
DNA damage results when UV light induces covalent bonds between nucleic acid base pairs and forms thymine dimers, which can alter tumor suppressor gene p53 function, thereby increasing the risk of cutaneous cancers and aging.
Topical application of ascorbic acid, along with vitamin E and ferulic acid, has been demonstrated to decrease the formation of thymine dimers.
One day later, skin was evaluated for erythema and sunburn cells, and immunohistochemically for thymine dimers and p53.
The topical combination was particularly effective for reducing thymine dimer mutations which are associated with skin cancer," explained Jacknin.
Specifically, UV-C light causes damage to the nucleic acid of microorganisms by the formation of lethal thymine dimers on the microbial DNA.
Clearly, it has the propensity to prevent cellular damage, as measured by sunburned cells and thymine dimers.
Compared with placebo, treated individuals with low baseline MED had a 50% reduction in epidermal sunburned (apoptotic) cells and nearly a 60% reduction in DNA damage, as measured by thymine dimer formation.
For years, thymine dimers were considered to be the classic sign of UV damage to DNA.
According to company executives, efficacy tests have demonstrated DN-AGE LS 9653's ability to protect both nuclear and mitochondrial DNA, reducing the formation of thymine dimers caused by UVB absorption and stimulating the natural DNA repair process in skin cells.
Compared with placebo, individuals with low baseline MED who were administered the hormone demonstrated a 50% reduction in epidermal sunburned (apoptotic) cells and nearly a 60% reduction in DNA damage, as measured by thymine dimer formation.