Exposure to ultraviolet light leads to a cell-wide DNA damage response that includes a global reduction in transcription. Williamson et al., identify a protein involved in this process as well as a noncoding RNA produced by alternative processing of RNA transcribed from the same gene that promotes recovery from the repressed state.

Ribonucleases H (RNases H) are endonucleases which cleave the RNA moiety of RNA/DNA hybrids. Their function in mammalian cells is incompletely understood. RNase H2 mutations cause Aicardi-Goutières syndrome, an inflammatory condition clinically overlapping with lupus erythematosus. We show that RNase H2 is essential in mouse embryonic development. RNase H2-deficient cells proliferated slower th...

Monosodium glutamate added to 12-day chick embryo retinas in culture causes severe morphologic damage to the retina as judged by light microscopic examination. Damage is evident after a few hours with concentrations as low as 0.3 mM. Glutamyltransferase induction is also appreciably inhibited by the amino acid. General protein synthesis and RNA synthesis appear to be less affected.

Background: RNA interference (RNAi) is a phenomenon uses double-stranded RNA (dsRNA) to specifically inhibit gene expression. The non-specific silencing caused by interferon response to dsRNA in mammalian cells limits the potential of utilizing RNAi to study gene function. Duplexes of 21-nucleotide short interfering dsRNA (siRNA) inhibit gene expression by RNAi. In some organisms, siRNA can als...

Living cells experience DNA damage as a result of replication errors and oxidative metabolism, exposure to environmental agents (e.g., ultraviolet light, ionizing radiation (IR)), and radiation therapies and chemotherapies for cancer treatments. Accumulation of DNA damage can lead to multiple diseases such as neurodegenerative disorders, cancers, immune deficiencies, infertility, and also aging...

Cells use transcription-coupled repair (TCR) to efficiently eliminate DNA lesions such as ultraviolet light-induced cyclobutane pyrimidine dimers (CPDs). Here we present the structure-based mechanism for the first step in eukaryotic TCR, CPD-induced stalling of RNA polymerase (Pol) II. A CPD in the transcribed strand slowly passes a translocation barrier and enters the polymerase active site. T...

Bacterial and mammalian AlkB proteins are iron(II)- and 2-oxoglutarate-dependent dioxygenases that reverse methylation damage, such as 1-methyladenine and 3-methylcytosine, in RNA and DNA. An AlkB-domain is encoded by the genome of numerous single-stranded, plant-infecting RNA viruses, the majority of which belong to the Flexiviridae family. Our phylogenetic analysis of AlkB sequences suggests ...

It is widely accepted that tumorigenesis is a multistep process characterized by the sequential accumulation of genetic alterations. However, the molecular basis of genomic instability in cancer is still partially understood. The observation that hereditary cancers are often characterized by mutations in DNA repair and checkpoint genes suggests that accumulation of DNA damage is a major contrib...

Schizophrenia is associated with a substantially increased somatic morbidity and mortality, which may partly be caused by accelerated cellular aging. Oxidative stress is an established mediator of aging and a suggested aetiological mechanism in both schizophrenia and age-related medical disorders such as cardiovascular disease, type 2 diabetes and dementia. We determined the urinary excretion o...