Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.30.2 (endonuclease)
18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We recently purified and cloned the gene for a DNA structure-specific endonuclease, FEN-1, from murine cells. The murine protein recognizes 5' DNA flap structures that have been proposed in DNA replication, repair, and recombination. Here, we report the sequence of the human FEN1 gene. The translated sequence is identical to peptide sequence obtained from maturation factor-1, which is 1 of the 10 essential proteins for cell-free DNA replication. The human protein has the same structure-specific DNA endonuclease activity as the murine protein. Two human chromosomal hybridization signals, 11q12 and 1p22.2, were observed by FISH analysis using human genomic clones homologous to the mouse Fen-1 gene. The localization on human 11q12 was confirmed using radiation-reduced hybrids. The mouse Fen-1 gene is assigned to chromosome 19 based on somatic cell hybrids. The significance of these FEN1 gene localizations in human and mouse is discussed.
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PMID:Sequence of human FEN-1, a structure-specific endonuclease, and chromosomal localization of the gene (FEN1) in mouse and human. 777 22

The efficiency of restriction endonuclease in situ digestion (REISD) with Sau3A to analyze chimerism and residual disease (RD) has been tested before and after an allogenic bone marrow transplant (BMT) in an acute lymphoblastic leukemia (ALL) patient. The combined results obtained with REISD and FISH using the appropriate probes for detecting chromosome rearrangements have proven to be useful for the identification and quantification of both the hemopoietic chimerism achieved after BMT and the RD persistent in the patient. The sensitivity of REISD has been determined to be around 95%, i.e., similar to that obtained by FISH. REISD with Sau3A was particularly useful in the analysis of chimerism since this enzyme revealed the polymorphic status of constitutive heterochromatin in human chromosome 3 and thus allowed discrimination of cells derived from donor and recipient. The method itself seems promising since neither a donor/recipient sex mismatch nor a cytogenetic disease marker are needed for its application.
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PMID:Restriction endonuclease in situ digestion (REISD) and fluorescence in situ hybridization (FISH) as complementary methods to analyze chimerism and residual disease after bone marrow transplantation. 869 21

FRA7G is an aphidicolin-inducible common fragile site at human chromosomal band 7q31.2. This region is frequently altered in a number of different tumor types including prostate, breast, and ovarian cancer. It has also been hypothesized that this region contains an important tumor suppressor gene which is mutated during the development of these cancers or an oncogene which is amplified. We previously used a FISH-based approach to isolate YAC clones which spanned FRA7G. In this report, we describe the isolation and restriction endonuclease mapping of three overlapping P1 clones which cover FRA7G and the region frequently altered in the different cancers. FISH-based analysis of these clones reveals that aphidicolin-induced breakage in the FRA7G region occurs over a region of at least 300 Kb in length. We have also localized a previously sequenced BAC clone to this region. The sequence obtained from this clone reveals the presence of an endogenous retroviral sequence (HERV-H) in the midst of the FRA7G region as well as sequences with homology to small polydispersed circular DNAs (spcDNAs). Thus for the first two cloned common fragile sites, FRA7G and FRA3B, there is an association with both spcDNAs and hot-spots for viral integration.
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PMID:FRA7G extends over a broad region: coincidence of human endogenous retroviral sequences (HERV-H) and small polydispersed circular DNAs (spcDNA) and fragile sites. 962 May 48

The pericentromeric heterochromatin contains tandemly repeated alphoid DNA sequences of about 171 bp in length. They are highly divergent from one chromosome to another due to chromosome specific alphoid subsets. In the present investigation, we used chromosome 18-specific centromeric probe (D18Z1) to evaluate the extent of pericentromeric heteromorphism classified by FISH-technique among 25 normal individuals. The hybridization signals were arbitrarily classified into five sizes when compared with the length of the short arm of chromosome 18. These are: negative (1), small (2), medium (3), large (4), and very large (5), with incidence of 0, 12, 24, 42, and 22 percent, respectively. Based on limited data, there were no chromosomes with negative signals while 42% of chromosome 18 had large-sized pericentromeric heterochromatin. The incidence observed earlier by restriction endonuclease Alu1 was different as compared to the present approach suggesting the complex heterogeneity of pericentric region of chromosome 18.
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PMID:Pericentromeric heteromorphism of human chromosome 18 as revealed by FISH-technique. 983 69

A 16-year-old girl with short stature, short neck, shield chest, and cubitus valgus was studied. FISH analyses of her structurally altered X chromosome showed a der(X)- (wcpX+,TelXp/Yp++,SHOX++,STS++,KAL-, 37A12-,DXZ1+,XIST++,97L7++,300O13-,404F- 18-,417G15-,404F18-,140A-,TelXq/Yq-). These results, together with the high-resolution banding analysis, indicated her karyotype to be 46,X,der(X)(Xpter-->Xp22.3::Xq22.3--> cen-->Xq22.3::Xp22.3-->Xpter). The der(X) was an isochromosome, consisting of duplicated terminal short arms and duplicated proximal long arms. This in turn suggested that the chromosome was formed through pericentric inversion of an X chromosome, followed by isochromosome formation through sister chromatid exchange at Xp, close to the centromere. Replication R-banding analysis showed that the abnormal X chromosome was late replicating. Analysis of digestion patterns with a methylation-sensitive restriction endonuclease of the phosphoglycerate kinase 1 gene, located in Xq13.3, indicated that its inactivation patterns were completely skewed.
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PMID:Isochromosome consisting of terminal short arm and proximal long arm X in a girl with short stature. 1124 89

Different approaches can be used to elucidate the unsolved questions concerning taxonomic evolution in cartilaginous fish. The study of the karyological characteristics of these vertebrates by combining molecular and traditional techniques of chromosome preparation and banding has been demonstrated to be a very effective method. In this paper we studied the localization and the composition of the constitutive heterochromatin by using C- and restriction endonuclease-banding in four selachian species, belonging to two of the four superorders. We also characterized two different types of repetitive genomic sequences in these species: satellite DNA and (TTAGGG)(n) telomeric sequences. Finally, we analysed the nuclear ribosomal gene to determine the number of the nucleolar organizers and their position on chromosomes by using silver staining, chromomycin A(3), and FISH (fluorescent in situ hybridization). The results showed a prevailingly telomeric localization of constitutive heterochromatin in the Galeomorphii, the presence of additional nucleolar organizer sites in Raja asterias, an exclusively telomeric localization of the (TTAGGG)(n) sequences in Scyliorhinus stellaris and both telomeric and interstitial in Taeniura lymma. These data, together with those concerning the conservation of the satellite DNA, seem to support the hypothesis that Chondrichthyes have an evolutionary history leading them to the acquisition of large genomes rich in highly repeated sequences and subjected to some selective pressures favoring the conservation of this DNA fraction.
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PMID:Karyotype and genome characterization in four cartilaginous fishes. 1235 64

Genomic fingerprints of mutagenic agents would have wide applications in the field of cancer biology, epidemiology and prevention. The differential spectra of chromosomal aberrations induced by different clastogens suggest that ratios of specific aberrations can be exploited as biomarkers of carcinogen exposure. We have tested this hypothesis using the novel technique of multicolor banding in situ hybridization (mBAND) in human peripheral blood lymphocytes exposed in vitro to X rays, neutrons, heavy ions, or the restriction endonuclease AluI. In the heavy-ion-irradiated cells, we further analyzed aberrations in chromosome 5 using multicolor FISH (mFISH). Contrary to the expectations of biophysical models, our results do not support the use of the ratios of inter-/intrachromosomal exchanges or intra-/interarm intrachanges as fingerprints of exposure to densely ionizing radiation. However, our data point to measurable differences in the ratio of complex/simple interchanges after exposure to different clastogens. These data should be considered in current biophysical models of radiation action in living cells.
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PMID:Chromosome intrachanges and interchanges detected by multicolor banding in lymphocytes: searching for clastogen signatures in the human genome. 1562 16

Many repair and recombination proteins play essential roles in telomere function and chromosome stability, notwithstanding the role of telomeres in "hiding" chromosome ends from DNA repair and recombination. Among these are XPF and ERCC1, which form a structure-specific endonuclease known for its essential role in nucleotide excision repair and is the subject of considerable interest in studies of recombination. In contrast to observations in mammalian cells, we observe no enhancement of chromosomal instability in Arabidopsis plants mutated for either XPF (AtRAD1) or ERCC1 (AtERCC1) orthologs, which develop normally and show wild-type telomere length. However, in the absence of telomerase, mutation of either of these two genes induces a significantly earlier onset of chromosomal instability. This early appearance of telomere instability is not due to a general acceleration of telomeric repeat loss, but is associated with the presence of dicentric chromosome bridges and cytologically visible extrachromosomal DNA fragments in mitotic anaphase. Such extrachromosomal fragments are not observed in later-generation single-telomerase mutant plants presenting similar frequencies of anaphase bridges. Extensive FISH analyses show that these DNAs are broken chromosomes and correspond to two specific chromosome arms. Analysis of the Arabidopsis genome sequence identified two extensive blocks of degenerate telomeric repeats, which lie at the bases of these two arms. Our data thus indicate a protective role of ERCC1/XPF against 3' G-strand overhang invasion of interstitial telomeric repeats. The fact that the Atercc1 (and Atrad1) mutants dramatically potentiate levels of chromosome instability in Attert mutants, and the absence of such events in the presence of telomerase, have important implications for models of the roles of recombination at telomeres and is a striking illustration of the impact of genome structure on the outcomes of equivalent recombination processes in different organisms.
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PMID:ERCC1/XPF protects short telomeres from homologous recombination in Arabidopsis thaliana. 1921 3

Human GATA3 haploinsufficiency leads to HDR (hypoparathyroidism, deafness, and renal dysplasia) syndrome. The development of a specific subset of organs in which this transcription factor is expressed appears exquisitely sensitive to gene dosage. We report on a 14-year-old patient with symptomatic hypoparathyroidism, sensorineural bilateral deafness, unilateral renal dysplasia, bilateral palpebral ptosis, and horizontal nystagmus. Fundoscopy displayed symmetrical pseudopapilledema, and brain CT scan revealed basal ganglia calcifications. FISH analysis did not disclose any microdeletion in the 22q11.2 or 10p14 regions. GATA3 mutation analysis identified a heterozygous deletion of GG nucleotides at codon 36 and 37 (c.108_109delGG) in exon 2 causing a frameshift with a premature stop codon after a new 15-aminoacid sequence. Restriction endonuclease analysis performed in parents was negative. Our patient carries a novel "de novo" GATA3 mutation, providing further evidence that HDR syndrome is caused by haploinsufficiency of GATA3, which may be responsible for a complex neurologic picture besides the known triad.
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PMID:HDR syndrome: a novel "de novo" mutation in GATA3 gene. 1924 80

Linker-adapter polymerase chain reaction (LA-PCR) is among the most efficient techniques for whole genome DNA amplification. The key stage in LA-PCR is the hydrolysis of a DNA sample with restriction endonucleases, and the choice of a restriction endonuclease (or several endonucleases) determines the composition of DNA probes generated in LA-PCR. Computer analysis of the localization of the restriction sites in human genome has allowed us to propose an efficient technique for generating DNA probes by LA-PCR using the restriction endonucleases HaeIII and RsaI. In silico hydrolysis of human genomic DNA with endonucleases HaeIII and RsaI demonstrate that 100- to 1,000-bp DNA fragments are more abundant in the gene-rich regions. Applying in situ hybridization to metaphase chromosomes, we demonstrated that the produced DNA probes predominantly hybridized to the C-negative chromosomal regions, whereas the FISH signal was almost absent in the C-positive regions. The described protocol for generating DNA probes may be successfully used in subsequent cytogenetic analysis of the C-negative chromosomal regions.
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PMID:A method for generating selective DNA probes for the analysis of C-negative regions in human chromosomes. 2181 Oct 56


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