Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1852044 (HS3)
 171 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human blood leukocytes were exposed to X rays to analyze the initial level of DNA breakage induced within different satellite DNA sequence areas and telomeres, using the DNA breakage detection-FISH procedure. The satellite DNA families analyzed comprised alphoid sequences, satellite 1, and 5-bp classical satellite DNA sequences from chromosome 1 (D1Z1 locus), from chromosome 9 (D9Z3 locus), and from the Y chromosome (DYZ1 locus). Since the control hybridization signal was quite different in each of the DNA targets, the relative increase in whole fluorescence intensity with respect to unirradiated controls was the parameter used for comparison. Irradiation of nucleoids obtained after protein removal demonstrated that the alkaline unwinding solution generates around half the amount of signal when breaks are present in the 5-bp classical DNA satellites as when the same numbers of breaks are present the genome overall, whereas the signal is slightly stronger when the breaks are within the alphoids or satellite 1 sequences. After correction for differences in sensitivity to the alkaline unwinding-renaturation, DNA housed in chromatin corresponding to 5-bp classical satellites proved to be more sensitive to breakage than the overall genome, whereas DNA in the chromatin corresponding to alphoids or satellite 1 showed a sensitivity similar to that of the whole genome. The minimum detectable dose was 0.1 Gy for the whole genome, 0.2 Gy for alphoids and satellite 1, and 0.4 Gy for the 5-bp classical satellites. Telomeric DNA sequences appeared to be maximally labeled in unirradiated cells. Thus telomeric ends behave like DNA breaks, constituting a source of background in alkaline unwinding assays.
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PMID:Radiation-induced DNA breaks in different human satellite DNA sequence areas, analyzed by DNA breakage detection-fluorescence in situ hybridization. 1200 51

Constitutive heterochromatin mainly consists of different classes of satellite DNAs and is defined as a transcriptionally inactive chromatin that remains compact throughout the cell cycle. The aim of this work was to investigate the level of condensation, methylation and transcriptional status of centromeric (alphoid DNA) and pericentromeric satellites (human satellite 3, HS3) in tissues (lymphocytes, placenta cells) and in cultured primary (MRC5, VH-10, AT2Sp) and malignant (A431) cells. We found that alphoid DNA remained condensed and heavily methylated in all the cell types. The HS3 of chromosome 1 (HS3-1) but not of chromosome 9 (HS3-9) was strongly decondensed and demethylated in A431 cells. The same observation was made for aged embryonic lung (MRC5) and juvenile foreskin (VH-10) fibroblasts obtained at late passages (32(nd) and 23(rd), respectively). Decondensation was also found in ataxia telangiectasia AT2Sp fibroblasts at the 16(th) passage. One of the manifestations of the disease is premature aging. The level of HS3-1 decondensation was higher in aged primary fibroblasts as compared to A431. The HS3-1 extended into the territory of neighbouring chromosomes. An RT-PCR product was detected in A431 and senescent MRC5 fibroblasts using primers specific for HS3-1. The RNA was polyadenylated and transcribed from the reverse chain. Our results demonstrate the involvement of satellite DNA in associations between human chromosomes and intermingling of chromosome territories. The invading satellite DNA can undergo decondensation to a certain level. This process is accompanied by demethylation and transcription.
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PMID:Human chromosome 1 satellite 3 DNA is decondensed, demethylated and transcribed in senescent cells and in A431 epithelial carcinoma cells. 1790 99