Estrogen receptor α (ERα) is the key transcriptional driver in a large proportion of breast cancers. We report that APOBEC3B (A3B) is required for regulation of gene expression by ER and acts by causing C-to-U deamination at ER binding regions. We show that these C-to-U changes lead to the generation of DNA strand breaks through activation of base excision repair (BER) and to repair by non-homo...

Deamination of cytosine to uracil is the most common promutagenic change in DNA, and it is greatly increased at the elevated growth temperatures of hyperthermophilic archaea. If not repaired to cytosine prior to replication, uracil in a template strand directs incorporation of adenine, generating a G.C --> A.U transition mutation in half the progeny. Surprisingly, genomic analysis of archaea ha...

Deoxycytosine methylase (Dcm) enzyme activity causes mutagenesis in vitro either directly by enzyme-induced deamination of cytosine to uracil in the absence of the methyl donor, S-adenosylmethionine (SAM), or indirectly through spontaneous deamination of [5-methyl]cytosine to thymine. Using a Lac reversion assay, we investigated the contribution of the first mechanism to Dcm mutagenesis in vivo...

Genomic methylation is variable under biotic and abiotic stresses in plants. In particular, viral infection is thought to significantly increase genomic methylation with particularly high activity around transposable elements. Here we present the genomic methylation profiles of grains of archaeological barley (Hordeum vulgare) from several strata from a site in southern Egypt, from the Napatan ...

The activation induced cytidine deaminase (AID) protein is known to initiate somatic hypermutation, gene conversion or switch recombination by cytidine deamination within the immunoglobulin loci. Using chromosomally integrated fluorescence reporter transgenes, we demonstrate a new recombinogenic activity of AID leading to intra- and intergenic deletions via homologous recombination of sequence ...

The toxicity of urea in mammals has long been a vexed question. Although most investigations seem to suggest that this snbstanee, as sueh, is not toxic, the possibility still exists that a sustained high level of urea in the blood may, in accordance with the law of mass action, result in tlie accumulation of intermediary nitrogenous compounds whieh are toxic. Since it has been shown (Schmidt et...

Deamination of DNA bases can create missense mutations predisposing humans to cancer and also interfere with other basic molecular genetic processes; this deamination generates deoxyinosine from deoxyadenosine. In Escherichia coli, the highly conserved endonuclease V is involved in alternative excision repair that removes deoxyinosine from DNA. However, its exact activities and roles in humans ...

Glutamate dehydrogenase, GDH (L-glutamate:NAD+ oxidoreductase (deaminating) EC 1.4.1.2) was purified from the plant fraction of lupin nodules and the purity of the preparation established by gel electrophoresis and electrofocusing. The purified enzyme existed as 4 charge isozymes with a MW of 270000. The subunit MW, as determined by dodecyl sulphate electrophoresis, was 45000. On the basis of t...