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In U. maydis the multiallelic b locus controls sexual and pathogenic development. In the b locus a gene coding for a regulatory protein had been identified, and it was suggested that the interaction of two b polypeptides specified by different alleles programs sexual development in this fungus. We now demonstrate the existence of a second regulatory gene in(More)
Mitochondrial DNA mutations play a major role in human aging processes and degenerative diseases. The most frequently reported marker for mutations of the mitochondrial DNA in human skin is a 4977 bp large-scale deletion, called the Common Deletion. Although this deletion is rarely detectable and constitutes only one example of the multitude of about 50,000(More)
Poly(ADP-ribose) (PAR) is a complex and reversible post-translational modification that controls protein function and localization through covalent modification of, or noncovalent binding to target proteins. Previously, we and others characterized the noncovalent, high-affinity binding of the key nucleotide excision repair (NER) protein XPA to PAR. In the(More)
Matrix metalloproteinase 1 (MMP-1) is widely regarded as a biomarker of photoageing. We tested the hypothesis that MMP-1 mRNA expression and erythema share a common action spectrum by comparing the effects of erythemally equivalent doses of UVB, UVA1 and solar simulated radiation (SSR) on acute MMP-1 mRNA expression in whole human skin in vivo. Our results(More)
The processes of aging and photoaging are associated with an increase in cellular oxidation. This may be in part due to a decline in the levels of the endogenous cellular antioxidant coenzyme Q10 (ubiquinone, CoQ10). Therefore, we have investigated whether topical application of CoQ10 has the beneficial effect of preventing photoaging. We were able to(More)
Smokers look older than non-smokers of the same age. We have compared the concentrations of mRNA for matrix metalloproteinase 1 (MMP-1) in the buttock skin of smokers and non-smokers with quantitative real-time polymerase chain reactions. MMP-1 degrades collagen, which accounts for at least 70% of the dry weight of dermis. We report significantly more MMP-1(More)
OBJECTIVE AND DESIGN Ultraviolet (UV) exposure induces local immunosuppression and inflammation in human skin. Cytokines are, in part, responsible for these responses. To investigate the effects of UV-induced gene expression at the molecular level we established a sensitive in vivo/ex vivo method for a comparative quantification of cytokines and receptors(More)
Repeated exposure to solar ultraviolet radiation results in premature skin aging due, in part, to the degradation of dermal collagen by fibroblast collagenase (matrix metalloproteinase 1 [MMP-1]). We have established TaqMan reverse transcription (RT) polymerase chain reaction (PCR) systems to quantify the messenger RNA (mRNA) expression of MMP-1 and its(More)
Animal and human studies have shown that low levels of folic acid are associated with an impaired DNA Repair Capacity (DRC) and an increased cancer risk. However, the molecular evidence that folic acid enhances the DRC of cultured human cells is still limited because of a paucity of in vitro studies. We investigated the effect of folic acid depletion in(More)
BACKGROUND The Host Cell Reactivation Assay (HCRA) is widely used to identify circumstances and substances affecting the repair capacity of cells, however, it is restricted by the transfection procedure used and the sensitivity of the detection method. Primary skin cells are particularly difficult to transfect, and therefore sensitive methods are needed to(More)