Clustered repair of excisable 4-nitroquinoline-1-oxide adducts in a larger fraction of genomic DNA of xeroderma pigmentosum complementation group C cells

Carcinogenesis
Y Fujiwara

Abstract

4-Nitroquinoline-1-oxide (4NQO) produced unstable and stable purine adducts to the DNA in human cells. Alkali-labile single-strand breaks (AL-SSBs) arose from 40% of the total adducts immediately after a 30 min alkali-denaturation of DNA. Near-ultraviolet (NUV) induced photochemical SSBs at each site of the remaining 60% adducts. Normal human, xeroderma pigmentosum group A (XPA) and C (XPC) cells removed rapidly all of the AL-SSBs and half of the 60% photobreakable adducts in a similar fashion. Thus, 60-70% labile 4NQO adducts in cells were suggested to be depurinated. Only 30-40% photo-breakable stable adducts of the total were excised almost completely in 24 h by nucleotide excision repair in normal cells, but remained unexcised in XPA cells. XPC cells excised approximately 50% of such excisable adducts in 6 h without further greater loss, as revealed by the kinetics of cumulative unscheduled DNA synthesis, excision-break accumulation and reduction in photochemical SSBs. Bimodal alkali-sucrose sedimentation profiles of photolysed DNA of growing and quiescent XPC cells following a 6 h repair of 4NQO damage presented the normal preferential excision repair in 50% of genomic DNA domains and no or greatly retarded repair in the r...Continue Reading

Related Concepts

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.