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)

Terminal deoxynucleotidyltransferase is an enzyme which has been found to be associated with thymus cells, bone marrow cells, as well as leukocytes from patients with acute lymphoblastic leukemia and chronic myelocytic leukemia in blast crisis. We report here the purification of terminal deoxynucleotidyltransferase by an oligonucleotide affinity (oligo(dT)12-18 cellulose) column. By using a 35 to 70% (NH4)2SO4 cut, Sephacryl S200 column and an oligo(dT) cellulose column, terminal deoxynucleotidyltransferase has been purified from calf thymus cells to a specific activity of more than 8,500 units/mg of protein. The terminal deoxynucleotidyltransferase purified by this method contains no detectable DNA-dependent DNA polymerase or endonuclease activities. Furthermore, sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the enzyme appears to be homogeneous, with two polypeptides corresponding to the two subunits alpha (10,000) and beta (23,000) of terminal deoxynucleotidyltransferase. These data indicate that oligo(dT)12-18 cellulose can be used as a rapid and selective affinity column for the purification of terminal deoxynucleotidyltransferase.
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PMID:Purification of terminal deoxynucleotidyltransferase by oligonucleotide affinity chromatography. 64 3

The Oka varicella vaccine strain can be differentiated from wild-type strains by its unique restriction endonuclease fingerprinting (REFP: HpaI-K and EcoRI-P) pattern of the gpV-coding region of the varicella-zoster virus (VZV) genome. VZV-DNAs from patients with complicated clinical courses related to vaccination were examined to determine whether they were vaccine-derived or wild-type. A virus was isolated from a one year-old boy with acute lymphocytic leukemia (ALL) who developed typical varicella 28 days after vaccination (case A). Another virus was isolated from a four-year-old boy without clinical symptoms following household contact with varicella patients at the age of two months, and he developed zoster 14 months after vaccination (case B). Also, two strains (OK1 and OK2) were isolated from household contacts (mother and sister) with a vaccine with ALL in Oklahoma who developed varicella 18 days after vaccination (case C). In case C, BgII-REFP did not determine conclusively whether the two strains (OK1 and OK2) were vaccine-derived or wild-type because the patterns obtained were different from both the Oka varicella vaccine strain and American wild-type strains [Gelb et al., Journal of Infectious Diseases, 155:633-640, 1987]. All VZV strains examined in the present study were identified as wild-type by our method using HpaI-K and EcoRI-P fragments as marker fragments. Thus it is becoming evident that REFP using HpaI and EcoRI endonucleases is a convenient and reliable means of distinguishing between the Oka vaccine virus strain and wild-type viruses isolated from individuals developing vesicular rashes shortly and long after varicella vaccination.
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PMID:Differentiation of oka varicella vaccine strain from wild varicella-zoster virus strains isolated from vaccinees and household contact. 167 58

We report the clinical evaluation of an improved DNA probe assay for the characteristic genetic marker of human CML, observed by cytogenetics and designated the Philadelphia chromosome (Ph1). The Ph1 chromosome results from the fusion of c-abl proto-oncogene sequences from chromosome 9 to phl gene sequence on chromosome 22. (The phl gene is often referred to as bcr. However, for clarity we prefer to reserve the designation "bcr" for the region within the phl gene in which translocation breakpoints have been found to occur. We also find it useful to distinguish between two such regions in phl, bcr-210 and bcr-190, named after the 210- and 190-kDa phl/abl fusion proteins resulting from translocations with breakpoints in the respective regions. We refer to the corresponding chromosomal translocations as Ph1(bcr-210) and Ph1(bcr-190).) DNA, extracted from peripheral blood (PB) or bone marrow (BM) and digested with restriction endonuclease BglII, is hybridized with a probe (phl/bcr-3) spanning a breakpoint cluster region within phl. Rearrangements are revealed by the presence of one or two novel junction fragments. Clinical specimens from leukemic patients with active disease were compared by cytogenetic and DNA probe analysis at seven centers in the United States and Europe. The probe assay identified the phl rearrangement in 190 of 191 cases of Ph1-positive CML, as well as in 12 of 27 clinically diagnosed CML specimens lacking a typical Ph1 chromosome. DNA rearrangements also were seen in two of six cases of Ph1-positive ALL. No false positive results were obtained among 93 non-leukemic controls. Mixing experiments showed that the DNA probe assay can detect as few as 1% leukemic cells in a specimen. A preliminary study of CML patients in remission after allogeneic BM transplantation revealed a small fraction of residual Ph1-positive leukemic cells in a significant number of such patients.
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PMID:Clinical evaluation of a DNA probe assay for the Philadelphia (Ph1) translocation in chronic myelogenous leukemia. 305 Feb 93

DNA of peripheral blood or bone marrow leukocytes from 8 normal subjects, 7 cases of acute lymphocytic leukemia (ALL), 2 of acute myelogenous leukemia (AML) and 1 of chronic myelogenous leukemia (CML), having been digested by endonuclease Eco RI or Pst I separately, was hybridized with the probes of 3' fragment (Pst I/Hind III) or 5' fragment (Hinc II/Pst I) of Abelson murine leukemia virus (A-MuLV) oncogene v-abl. The proto-oncogene c-abl, which is homologous to v-abl, was found amplified in 4 ALL, 1 CML and 1 AML. In one of these 4 ALL, c-abl was amplified even over 100 times. A new c-abl BamH I fragment with 6.7 kilobase pairs (kb) in length was observed in 2 ALL and 1 CML out of these 6 cases with amplification, but none of this fragment was found in the normal subjects or other leukemia patients. These 3 patients with the presence of 6.7 kb fragment were high risk ones and 2 of them had died, suggesting that 6.7 kb fragment be the index of poor prognosis. The amplification and rearrangement of c-abl imply the activation of proto-oncogene in leukemogenesis.
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PMID:[Amplification and rearrangement of proto-oncogene c-abl in human leukemia cells]. 321 75

A cDNA clone representing the gene encoding the beta chain of the human T-cell antigen receptor has been isolated recently. By using fragments of this cDNA as hybridization probes in Southern blot analysis of restriction endonuclease-digested genomic DNA, we have now examined the structure of the gene in DNA from 26 patients with acute leukemia and from 23 normal individuals. We have found that the T-cell antigen receptor gene has undergone somatic rearrangement in 14 of 14 patients with the phenotypic diagnosis of T-cell acute lymphoblastic leukemia. In this group of patients, similar patterns of rearrangement appear to occur in different patients. This finding suggests that there is either a limited repertoire of possible rearrangements or an association between the development of leukemia and specific patterns of rearrangement. DNA from 6 patients with acute myeloblastic leukemia, 6 patients with non-B, non-T acute lymphoblastic leukemia, and 23 nonleukemic individuals showed no rearrangement or polymorphism. One case of T-cell acute lymphoblastic leukemia, however, showed rearrangement of both the T-cell receptor beta chain and the constant region of the immunoglobulin gene. Studies with mixtures of DNAs from leukemic bone marrow cells and cultured skin fibroblasts, as well as with remission and relapse marrow DNAs from the same patients, indicate that this technique can detect 1% leukemic cells in a mixed population. In addition, DNA from the marrow of a patient in relapse contains a similar rearrangement to that found in the marrow sample taken at the time of diagnosis, which suggests that the original clone of leukemic cells was responsible for relapse. Our results indicate that assessment of rearrangement of the T-cell antigen receptor gene will be valuable in the diagnosis and management of leukemia and can be used to evaluate clonality in T-cell neoplasia.
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PMID:Somatic rearrangement of T-cell antigen receptor gene in human T-cell malignancies. 385 57

We report the molecular analysis of an 8;14 reciprocal chromosome translocation in a case of acute lymphocytic leukemia (L3 type). DNA from primary leukemic cells was analyzed on the basis of restriction endonuclease mapping by hybridization with various human c-myc and Ig heavy chain probes. The breakpoint of the translocation is within an approximately equal to 200-base-pair region in the first intron of the c-myc gene. The first, untranslated exon thereby remains on chromosome 8q-, whereas the whole protein-coding region is rearranged in the C alpha 1 locus on chromosome 14q+. RNA transfer blot analysis showed high levels of at least two different c-myc transcripts originated from the translocated gene. Both differ in size from the normal 2.2- and 2.4-kilobase transcripts. Both c-myc structure and expression were apparently normalized in remission phase. These studies demonstrate rearrangement and abnormal expression of c-myc in primary cells from an acute leukemia patient, thus adding to the concept of a key role for c-onc in human oncogenesis.
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PMID:Translocation and rearrangement of c-myc into immunoglobulin alpha heavy chain locus in primary cells from acute lymphocytic leukemia. 608 8

The previously established fact of low activity of Ca, Mg-dependent endonucleolysis of cell nucleus DNA in lymphoproliferative diseases (CME-activity) brought the authors to study intranuclear characteristics of lymphoid cells in childhood acute lymphoblastic leukemia (ALL). The intensity of DNA-endonucleolysis was measured in 0.7% agarose gel using electrophoresis. Peripheral blood and bone marrow samples from 13 untreated ALL patients and 23 children in remission were examined. The age of the patients ranged from 4 to 14 years. CME-activity before treatment appeared to be 2-10 times less than normal in 8 out of 13 patients. In bone marrow cell nuclei CME-activity was universally reduced 3-20-fold. In ALL remission endonuclease activity in blood and bone marrow cells returned to normal.
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PMID:[Changes in the activity of endonucleolysis of nuclear DNA in children with acute leukemia]. 764 86

Glucocorticoids (GC) are being used in the treatment of childhood leukemia for several decades, most successfully in newly diagnosed acute lymphoblastic leukemia (ALL). However, GC resistance is seen in 10-30% of untreated ALL patients, and is much more frequent in relapsed ALL and in acute nonlymphoblastic leukemia (ANLL). Sensitivity or resistance to GC can be measured using a cell culture drug resistance assay. For this purpose, we use the colorimetric methyl-thiazol-tetrazolium (MTT) assay. We have shown that GC resistance in childhood leukemia is related to clinical and cell biological features, and to the clinical outcome after multi-drug chemotherapy. These results are summarized in this review. In addition, we describe the apoptotic 'cell-lysis pathway' by which GC exert their antileukemic activity. This description provides a model to discuss the mechanisms of GC resistance, and to summarize the relevant literature. Possible levels of resistance relate to the diffusion of GC through the cell membrane, binding to the GC receptor (GCR), activation of the GC-GCR complex, translocation of the complex into the nucleus, binding to DNA, endonuclease-mediated DNA fragmentation, and DNA repair. A low number of GCR has been shown to be the cause of resistance in some children with ALL. However, GC resistance is likely to be caused at the post-receptor level in most leukemias. Unfortunately, there is still a lack of knowledge relating to the clinical relevance of mechanisms of GC resistance at the post-receptor level. Studies on the mechanisms of GC resistance other than those directly related to the GCR should be initiated, especially if patient material is used, as the results might indicate ways to circumvent or modulate GC resistance. A further increase in our knowledge regarding the relation between GC resistance and patient and cell biological features, the clinical relevance of GC resistance, and the mechanisms of GC resistance in leukemia patients, may contribute to further improvement in the results of GC therapy in leukemia.
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PMID:Glucocorticoid resistance in childhood leukemia. 804 44

The Philadelphia (Ph) translocation [t(9;22)(q34;q11)] is the most common genetic abnormality in human leukemia; a transposition of the ABL gene to the major-breakpoint cluster region (M-BCR) is associated with the pathogenesis in Ph+ chronic myelogenous leukemia (Ph+ CML) and in some cases of Ph+ acute leukemia (Ph+ AL). Our current understanding of the methylation of human genomes allows us to consider the association between the epigenetic phenomenon and the control of differentiation and proliferation in mammalian cells. In order to determine whether the methylation status of the M-BCR is associated with breakpoint-localization in this region and with the lineage of hematopoietic cells, we have examined 28 patients with Ph+ leukemias, including nine with Ph+ AL, six patients with acute myeloblastic leukemia without Ph (Ph- AML), and five patients with Ph- acute lymphoblastic leukemia (Ph- ALL); using the restriction endonuclease isochizomers, MspI and HpaII. In CML patients in the chronic phase, the hypomethylated status within the normal M-BCR allele is heterogeneous. In contrast, patients with Ph+ CML in the lymphoid blast crisis phase exhibited a 2.5/2.7 kb band with a complete disappearance of the germline M-BCR fragment (type L). This pattern is consistently noted in Ph- ALL cells, and the pattern is quite different from that found in myeloid blast crisis or Ph- AML (type M). In patients with M-BCR-nonrearranged Ph+ ALL, it is suggested that the M-BCR methylation patterns are cell-lineage specific but some Ph+ ALL cells had a hypomethylation pattern that was identical to that observed in Ph- AML, suggesting a distinction of genetic diversity of leukemia cells with the Ph chromosome, especially Ph+ AL.
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PMID:The methylation status of the major breakpoint cluster region in human leukemia cells, including Philadelphia chromosome-positive cells, is linked to the lineage of hematopoietic cells. 850 75

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


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