Terminology

DNA Glycosylase

DNA glycosylases are a family of enzymes involved in base excision repair

Base excision repair is the mechanism by which damaged bases in DNA are removed and replaced. DNA glycosylases catalyze the first step of this process. They remove the damaged nitrogenous base while leaving the sugar-phosphate backbone intact, creating an apurinic/apyrimidinic site, commonly referred to as an AP site. This is accomplished by flipping the damaged base out of the double helix followed by cleavage of the N-glycosidic bond.

DNA AP lyase Apurinic/Apyrimidinic Lyase

An enzyme that catalyzes the cleavage of the C-O-P bond 3' from the apurinic or apyrimidinic site in DNA via β-elimination reaction, leaving a 3'-terminal unsaturated sugar and a product with a terminal 5'-phosphate.

In the 1970s, this class of enzyme was found to repair at apurinic or apyrimidinic DNA sites in E. coli and in mammalian cells. This enzyme is part of a family of lyases that cleave carbon-oxygen bonds.

The major active enzyme of this class in bacteria, and specifically, E. coli is endonuclease type III

Rad50

A protein involved in DNA double-strand break repair.

Rad50 is a member of the structural maintenance of chromosomes (SMC) family of proteins.

This protein forms a complex with MRE11 and NBS1 (also known as Xrs2 in yeast).

• This MRN complex (MRX complex in yeast) binds to broken DNA ends and displays numerous enzymatic activities that are required for double-strand break repair by nonhomologous end-joining or homologous recombination.

Recalcitrant Seeds

Are those that cannot withstand desiccation, presenting significant challenges for long-term storage, often requiring cryopreservation in liquid nitrogen.

Orthodox Seeds

Produced by a wide range of plant species, possess desiccation tolerance and are readily stored through conventional freezing.

Genes

AtOGG1

A DNA glycosylase/apurinic/apyrimidinic (AP) lyase that is involved in base excision repair for eliminating 8-oxo-G from DNA.

The transcript of AtOGG1 was detected in seeds, and it was strongly up-regulated during seed desiccation and imbibition.

Research Articles

NBS1 plays a synergistic role with telomerase in the maintenance of telomeres in Arabidopsis thaliana Najdekrova et al. 2012 Research Article

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Morphological and Physiological Framework Underlying Plant Longevity in Arabidopsis thaliana Wang et al. 2020 Research Article

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Homologous recombination in planta is stimulated in the absence of Rad50 Gherbi et al. 2001 Research Article

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Arabidopsis TAF1 is an MRE11-interacting protein required for resistance to genotoxic stress and viability of the male gametophyte Waterworth et al. 2015 Research Article

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Overexpression of AtOGG1, a DNA glycosylase/AP lyase, enhances seed longevity and abiotic stress tolerance in Arabidopsis Chen et al. 2012 Research Article

"Overexpression of AtOGG1 in Arabidopsis enhanced seed resistance to controlled deterioration treatment."

"In addition, the content of 8-hydroxy-2# deoxyguanosine (8-oxo-dG) in transgenic seeds was reduced compared to wild-type seeds, indicating a DNA damage repair function of AtOGG1 in vivo."

A plant DNA ligase is an important determinant of seed longevity Waterworth et al. 2010 Research Article

"Here, phenotypic analysis of atlig6 mutant plants reveals that this DNA ligase plays important roles in seed germination and seed longevity, particularly under genotoxic stress conditions. "

"Likewise, the delayed germination observed in atlig4 mutants, together with the rapid DNA damage transcriptional response detected in imbibing seeds, suggests that double-strand breaks (DSBs) and their associated repair pathways influence germination performance. "

"Overall, these findings highlight significant roles for DNA ligases in maintaining seed vigor and viability during storage under suboptimal conditions, such as those commonly encountered in developing regions."

"This DSB-induced DNA damage response resulted in the significant upregulation of transcripts within 3 h of imbibition (Figure 8a)", with peaks around 6 hours.