Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0043346 (xeroderma pigmentosum)
 2,924 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have examined the incorporation of biotinyl-11-deoxyuridine triphosphate (BiodUTP) into excision repair patches of UV-irradiated confluent human fibroblasts. Cells were reversibly permeabilized to BiodUTP with lysolecithin, and biotin was detected in DNA on nylon filters using a streptavidin/alkaline phosphatase colorimetric assay. Following a UV dose of 12 J/m2, maximum incorporation of BioUTP occurred at a lysolecithin concentration (80-100 micrograms/mL) similar to that for incorporation of dTTP. Incorporation of BiodUTP into repair patches increased with UV dose up to 4 and 8 J/m2 in two normal human fibroblast strains, while no incorporation of BiodUTP was observed in xeroderma pigmentosum (group A) human fibroblasts. The repair-incorporated biotin was not removed from the DNA over a 48-h period, and only slowly disappeared after longer times (approximately 30% in 72 h), while little of the biotin remained in cells induced to divide. Furthermore, the stability of the biotin in repaired DNA was unaffected by a second dose of UV radiation several hours after the biotin-labeling period to induce a "second round" of excision repair. Exonuclease III digestion and gap-filling with DNA polymerase I indicate that the majority of biotin-labeled repair patches (approximately 80%) are rapidly ligated in confluent human cells. However, the remaining patches were not ligated after a 24-h chase period, in contrast to dTTP-labeled repair patches. The BiodUMP repair label in both chromatin and DNA is preferentially digested by staphylococcal nuclease, preventing the use of this enzyme for nucleosome mapping in these regions.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Characterization of biotinylated repair regions in reversibly permeabilized human fibroblasts. 147 61

Neocarzinostatin (NCS) induces repair in a xeroderma pigmentosum lymphoblastoid line deficient in the ability to repair DNA damage induced with (acetoxyacetyl-amino)fluorene. Repair was demonstrated by the induction of repair synthesis and by the disappearance of NCS-induced single-strand breaks and/or alkaline-labile sites in DNA. Estimation of NCS-induced repair patch size, based on the density shift induced in DNA by extensive shear after incubation of treated cells in medium with bromodeoxyuridine or by calculation from the extent of restoration of DNA sedimentation profiles in alkaline sucrose gradients and the amount of repair synthesis measured by the BND cellulose method, indicated that only a few nucleotides were inserted per repaired region. NCS-treated bacteriophage T7 DNA requires incubation with alkaline phosphatase to make it a substrate for DNA polymerase I. NCS-reacted T7 DNA, even after phosphatase treatment, is not a substrate for a DNA polymerase alpha obtained from human lymphoma cells. NCS-treated T7 DNA did serve as a substrate for the DNA polymerase alpha when incubated with an apurinic/apyrimidinic (AP) endonuclease with associated 5'-3'-exonuclease activity. The results suggest that NCS-induced AP sites could be intermediates for the in vivo repair synthesis.
 ...
PMID:Repair of neocarzinostatin-induced deoxyribonucleic acid damage in human lymphoblastoid cells: possible involvement of apurinic/apyrimidinic sites as intermediates. 625 59

In order to conveniently measure cellular DNA repair in immortalized and primary human cells we have combined the features of high cellular infectivity of adenovirus (Ad) with that of host-cell reactivation (HCR) of ultraviolet light (UV)-damaged reporter genes. We show that Ads having either the cat (chloramphenicol acetyltransferase) or seap (secreted alkaline phosphatase) reporter gene under control of a strong constitutive promoter can be used to measure relative levels of DNA repair by HCR. Most importantly, the SEAP assay allows for a convenient, inexpensive, and sensitive colorimetric microtiter assay. Only a few steps are involved and it is possible to process many samples simultaneously in a relatively short time, which is not as easily done with other reporter gene assays. Furthermore, we show that co-infection of UV-damaged SEAP Ad with an Ad carrying a prokaryotic repair gene significantly increased the HCR levels in xeroderma pigmentosum cells. The Ad gene delivery system, and the SEAP assay in particular, should simplify existing HCR assays considerably. By using non-lytic Ad as a vehicle it should be possible to quantitatively introduce normal or dominant negative mutant DNA repair genes into bulk cell populations for DNA repair studies.
 ...
PMID:Host-cell reactivation of reporter genes introduced into cells by adenovirus as a convenient way to measure cellular DNA repair. 752