Disease relevance of DNTT

• The four mutant forms of terminal transferase were also overexpressed in the baculovirus expression system and purified from Trichoplusia ni larvae by a monoclonal antibody affinity column and compared with wild-type enzyme with respect to thermostabilities, secondary structure, metal effects, and kinetic parameters [1].
• Apoptosis was also observed in xenografts of human cervical cancer cells infected with sense p21 adenovirus, as confirmed by in situ terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) [2].
• Terminal transferase as a predictor of initial responsiveness to vincristine and prednisone in blastic chronic myelogenous leukemia: a co-operative study [3].
• Marrow terminal deoxynucleotidyltransferase values obtained during the active phase of acute lymphoblastic leukemia were significantly greater than those found in other types of leukemia, bone marrow malignancies, and hematologic disorders [4].
• Terminal transferase determinations in blast cells of two patients with leukemic conversion of non-Hodgkin's lymphoma and in tumor cells from one patient with Burkitt's lymphoma were within the control range [4].

Psychiatry related information on DNTT

• To address this controversy we recruited a sample of 316 patients with anorexia nervosa from six European centres, and utilised a family-based transmission disequilibrium (TDT) approach to analyse the HTR2A-1438 G/A polymorphism [5].
• We examined the degeneration of neocortical neurons in normal aging and Alzheimer's disease (AD) using terminal transferase (TdT)-mediated deoxyuridine triphosphate (d-UTP)-biotin nick-end labeling (TUNEL), a method that identifies DNA strand breaks and constitutes a positive marker for dying neurons [6].
• TDT-association analysis of EKN1 and dyslexia in a Colorado twin cohort [7].
• With prolonged reaction-time the terminal transferase-mediated DNA-end labeling revealed a signal in 2.0 +/-1.2% melanin-containing cells in PD compared to 1.3 +/-1.1% in control [8].
• Using haplotype-based haplotype relative risk (HHRR) and transmission/disequilibrium (TDT) analyses, no evidence was found for an association of 5HT-2A with bipolar affective disorder under the assumption of no imprinting and of imprinting [9].

High impact information on DNTT

• In the last few years the number of known pols, including terminal transferase and telomerase, has increased to at least 19 [10].
• The human telomere terminal transferase enzyme is a ribonucleoprotein that synthesizes TTAGGG repeats [11].
• Alternatively, a novel method using MPE X FE(II) as a probe and directly labeling the 3' ends with terminal transferase was implemented [12].
• Down-regulation of TDT transcription in CD4(+)CD8(+) thymocytes by Ikaros proteins in direct competition with an Ets activator [13].
• In contrast to the activity of fas in other cellular systems, dying OLs did not exhibit evidence of apoptosis, assessed morphologically and by terminal transferase-mediated d-uridine triphosphate-biotin nick-end-labeling staining for DNA fragmentation [14].

Chemical compound and disease context of DNTT

• Apoptosis of human colon adenocarcinoma cell lines, including Colo 205, was determined by the Annexin V method and terminal deoxynucleotidyltransferase-mediated deoxyuridine 5'-triphosphate nick-end labeling (TUNEL) [15].
• Inhibition of endogenous NO synthesis did not affect cell cycle progression of melanoma cells but led to cell death by apoptosis, as indicated by Annexin V/propidium iodide and terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling assays [16].
• The CYP2E1-dependent arachidonic acid toxicity appeared to involve apoptosis, as demonstrated by terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling and DNA laddering experiments [17].
• Minocycline reduced tubular cell apoptosis 24 h after ischemia as determined by terminal transferase-mediated dUTP nick end-labeling staining and nuclear morphology [18].
• Our findings demonstrate that Ang II (100 nM, 24 h) alone upregulates HO-1 expression and induces both myocyte hypertrophy and apoptosis, assessed by measuring terminal deoxynucleotidyltransferase dUTP nick-end labelling (TUNEL) staining, caspase-3 activity and mitochondrial membrane potential [19].

Biological context of DNTT

• BACKGROUND: Terminal deoxynucleotidyltransferase (TdT) is a DNA polymerase that enhances the Ig and TcR gene diversity in the N region at the junctions of variable (V), diversity (D) and joining (J) segments in B- and T-cells [20].
• Terminal deoxynucleotidyltransferase forms a ternary complex with a novel chromatin remodeling protein with 82 kDa and core histone [20].
• Apoptosis of tumor tissue cells was assayed by the terminal transferase uridyl nick end labeling (TUNEL) method [21].
• Chromosome localization of the gene for human terminal deoxynucleotidyltransferase to region 10q23-q25 [22].
• DNA polymerase mu (pol mu) is a novel error-prone DNA repair enzyme bearing significant structural homology with terminal deoxynucleotidyltransferase [23].

Anatomical context of DNTT

• Using an anti-TdT antibody column, TdT has been purified as a member of a megadalton protein complex from rat thymus [24].
• DNA polymerase mu (Pol mu), homologous to TdT, could act as a DNA mutator in eukaryotic cells [25].
• The level of TdT expression was assayed by competitive PCR amplification and compared with thymocytes and peripheral blood lymphocytes [26].
• Evidence against T-cell development in the adult human intestinal mucosa based upon lack of terminal deoxynucleotidyltransferase expression [26].
• I have identified an activity in crude HeLa cell extracts that satisfies the requirements for a human telomere terminal transferase or telomerase [11].

Associations of DNTT with chemical compounds

• Furthermore, using methanol-fixed cells, it could be shown that approximately 20% contained intracytoplasmic mu chains (cyto-mu) and that approximately 15% were positive for the terminal transferase enzyme (TdT) marker [27].
• The induction of apoptosis was evaluated by using the terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling assay and propidium iodide staining [28].
• Biochemical alterations included membrane phosphatidylserine exposure and DNA fragmentation, as evaluated by in situ annexin V and terminal deoxynucleotidyltransferase-mediated dUTP end labeling (TUNEL) assays, respectively [29].
• The procedure is based on the following: (i) a terminal deoxynucleotidyltransferase is used to add a biotinylated nucleotide (Bio-11-dUTP) tail to the 3' hydroxyl terminus generated by the action of a restriction enzyme and (ii) the biotinylated oligonucleotide is detected by a peroxidase-based immunocytochemical method [30].
• By the time the nuclear DNA was susceptible to heavy label by terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling, the ricinosomes had released into the cytoplasm their content of cysteine endoprotease, which became activated because of the cleavage of its propeptide [31].

Physical interactions of DNTT

• CONCLUSIONS: TdIF2 binds directly to TdT and core histone [20].
• TdT interacts with PCNA in its DNA polymerization domain (DPD), but not in its BRCA-1 C-terminal (BRCT) domain [24].

Enzymatic interactions of DNTT

• These findings suggest that TdT catalyses the addition of N nucleotides under the negative control of PCNA during V(D)J recombination [24].
• However, since DNA fragmentation also occurs in cellular necrosis, we studied to which extent the use of DNA polymerase (nick translation) or terminal transferase (tailing) allows the differentiation between internucleosomal DNA degradation, typical for apoptosis, and the more random DNA destruction in necrosis [32].

Regulatory relationships of DNTT

• Terminal deoxynucleotidyltransferase is negatively regulated by direct interaction with proliferating cell nuclear antigen [24].
• The susceptibility of T cells to undergo TNF-induced apoptosis was analyzed using terminal deoxynucleotidyltransferase-mediated UTP-end-labeling (TUNEL) and DNA ladder assays [33].

Other interactions of DNTT

• TdIF2 reduces the TdT activity to 46% of its maximum value in vitro assay system using activated DNA as primer [20].
• The interaction between PCNA and TdT was confirmed by co-immunoprecipitation, both in vitro and in vivo [24].
• DNA polymerase lambda contains template-dependent (DNA polymerase) and template-independent (terminal transferase) activities [34].
• RESULTS: Terminal deoxynucleotidyltransferase-mediated biotin-dUTP nick-end labeling (TUNEL) or cleaved caspase-3 and cleaved PARP could not be detected [35].
• Treatment of the OLs with varying concentrations of NGF over a range of time periods resulted in no significant increase in numbers of terminal transferase (TdT)-mediated d-uridine triphosphate (UTP)-biotin nick-end labeling positive OLs, whereas significant cell death was observed using TNF-alpha [36].

Analytical, diagnostic and therapeutic context of DNTT

• TdT binds directly to a PCNA trimer, as shown by gel filtration [24].
• Detection of leukaemic lymphoblasts in CSF by immunofluorescence for terminal transferase [37].
• Anaphase bridges were found in all cases, and fluorescence in situ hybridization demonstrated extensive structural rearrangements of chromosomes, with terminal transferase detection showing fragmented DNA in 5-20% of interphase cells [38].
• The solid-phase immunoassay was greater than 100-fold more sensitive than conventional assays for enzyme activity, rendering it potentially useful for quantitatively monitoring terminal transferase in patients with leukemia [39].
• HL-T, a new cell line derived from HL-60 promyelocytic leukemia cell cultures expressing terminal transferase and secreting suppressor activity [40].

References