TTL

Gene Summary

Gene:TTL; tubulin tyrosine ligase
Location:2q13
Summary:TTL is a cytosolic enzyme involved in the posttranslational modification of alpha-tubulin (see MIM 602529). Alpha-tubulin within assembled microtubules is detyrosinated over time at the C terminus. After microtubule disassembly, TTL restores the tyrosine residues and consequently participates in a cycle of tubulin detyrosination and tyrosination (Erck et al., 2003 [PubMed 14571137]).[supplied by OMIM, Mar 2008]
Databases:OMIM, HGNC, GeneCard, Gene
Protein:tubulin--tyrosine ligase
HPRD
Source:NCBIAccessed: 06 August, 2015

Ontology:

What does this gene/protein do?
Show (5)

Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 06 August 2015 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Genetic Markers
  • Xeroderma Pigmentosum Group D Protein
  • Polymerase Chain Reaction
  • Lung Cancer
  • Breast Cancer
  • Neoplastic Cell Transformation
  • Apoptosis
  • Tumor Burden
  • Genotype
  • Translocation
  • Xenobiotics
  • DNA Damage
  • Acute Lymphocytic Leukaemia
  • DNA Mutational Analysis
  • Chromosome 2
  • Lymphatic Metastasis
  • Cohort Studies
  • Reactive Oxygen Species
  • Chromosome Aberrations
  • Young Adult
  • Biological Markers
  • Smoking
  • Benzo(a)pyrene
  • Protein Isoforms
  • Asbestos
  • Signal Transduction
  • DNA-Binding Proteins
  • Chromosome 13
  • Maternal-Fetal Exchange
  • U2AF1
  • FISH
  • Carcinogens
  • TTL-ETV6 fusion
  • Polymorphism
  • Mutation
  • Tobacco Smoke Pollution
  • Oligonucleotide Array Sequence Analysis
  • Genetic Predisposition
  • Restriction Fragment Length Polymorphism
Tag cloud generated 06 August, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (3)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: TTL (cancer-related)

Pacak K, Sirova M, Giubellino A, et al.
NF-κB inhibition significantly upregulates the norepinephrine transporter system, causes apoptosis in pheochromocytoma cell lines and prevents metastasis in an animal model.
Int J Cancer. 2012; 131(10):2445-55 [PubMed] Free Access to Full Article Related Publications
Pheochromocytomas (PHEOs) and paragangliomas (PGLs) are specific types of neuroendocrine tumors that originate in the adrenal medulla or sympathetic/parasympathetic paraganglia, respectively. Although these tumors are intensively studied, a very effective treatment for metastatic PHEO or PGL has not yet been established. Preclinical evaluations of novel therapies for these tumors are very much required. Therefore, in this study we tested the effect of triptolide (TTL), a potent nuclear factor-kappaB (NF-κB) inhibitor, on the cell membrane norepinephrine transporter (NET) system, considered to be the gatekeeper for the radiotherapeutic agent 131I-metaiodobenzylguanidine (131I-MIBG). We measured changes in the mRNA and protein levels of NET and correlated them with proapoptotic factors and metastasis inhibition. The study was performed on three different stable PHEO cell lines. We found that blocking NF-κB with TTL or capsaicin increased both NET mRNA and protein levels. Involvement of NF-κB in the upregulation of NET was verified by mRNA silencing of this site and also by using NF-κB antipeptide. Moreover, in vivo treatment with TTL significantly reduced metastatic burden in an animal model of metastatic PHEO. The present study for the first time shows how NF-κB inhibitors could be successfully used in the treatment of metastatic PHEO/PGL by a significant upregulation of NET to increase the efficacy of 131I-MIBG and by the induction of apoptosis.

Meyer LH, Eckhoff SM, Queudeville M, et al.
Early relapse in ALL is identified by time to leukemia in NOD/SCID mice and is characterized by a gene signature involving survival pathways.
Cancer Cell. 2011; 19(2):206-17 [PubMed] Related Publications
We investigated the engraftment properties and impact on patient outcome of 50 pediatric acute lymphoblastic leukemia (ALL) samples transplanted into NOD/SCID mice. Time to leukemia (TTL) was determined for each patient sample engrafted as weeks from transplant to overt leukemia. Short TTL was strongly associated with high risk for early relapse, identifying an independent prognostic factor. This high-risk phenotype is reflected by a gene signature that upon validation in an independent patient cohort (n = 197) identified a high-risk cluster of patients with early relapse. Furthermore, the signature points to independent pathways, including mTOR, involved in cell growth and apoptosis. The pathways identified can directly be targeted, thereby offering additional treatment approaches for these high-risk patients.

Metsola K, Kataja V, Sillanpää P, et al.
XRCC1 and XPD genetic polymorphisms, smoking and breast cancer risk in a Finnish case-control study.
Breast Cancer Res. 2005; 7(6):R987-97 [PubMed] Free Access to Full Article Related Publications
INTRODUCTION: It has been suggested that individuals with reduced DNA repair capacities might have increased susceptibility to environmentally induced cancer. In this study, we evaluated if polymorphisms in DNA repair genes XRCC1 (Arg280His, Arg399Gln) and XPD (Lys751Gln) modify individual breast cancer risk, with emphasis on tobacco smoking.
METHODS: The study population consisted of 483 incident breast cancer cases and 482 population controls of Finnish Caucasian origin. The genotypes were determined by PCR-RFLP-based methods. Odds ratio (OR) and confidence intervals (CIs) were calculated by unconditional logistic regression analyses.
RESULTS: No statistically significant overall effect in the breast cancer risk was seen for any of the studied polymorphisms. However, a significant increase in breast cancer risk was seen among ever smoking women if they carried at least one XRCC1-399 Gln allele (OR 2.33, 95% CI 1.30-4.19, pint 0.025) or XPD-751 Gln/Gln genotype (OR 2.52, 95% CI 1.27-5.03, pint 0.011) compared to smoking women not carrying these genotypes. The risks were found to be confined to women smoking at least five pack-years; the respective ORs were 4.14 (95% CI 1.66-10.3) and 4.41 (95% CI 1.62-12.0). Moreover, a significant trend of increasing risk with increasing number of the putative at-risk genotypes (p for trend 0.042) was seen. Women with at least two at-risk genotypes had an OR of 1.54 (95% CI 1.00-2.41) compared to women with no at-risk genotypes. Even higher estimates were seen for ever actively smoking women with at least two at-risk genotypes.
CONCLUSION: Our results do not indicate a major role for XRCC1 and XPD polymorphisms in breast cancer susceptibility, but suggest that they may modify the risk especially among smoking women.

Husgafvel-Pursiainen K
Genotoxicity of environmental tobacco smoke: a review.
Mutat Res. 2004; 567(2-3):427-45 [PubMed] Related Publications
Environmental tobacco smoke (ETS), or second-hand smoke, is a widespread contaminant of indoor air in environments where smoking is not prohibited. It is a significant source of exposure to a large number of substances known to be hazardous to human health. Numerous expert panels have concluded that there is sufficient evidence to classify involuntary smoking (or passive smoking) as carcinogenic to humans. According to the recent evaluation by the International Agency for Research on Cancer, involuntary smoking causes lung cancer in never-smokers with an excess risk in the order of 20% for women and 30% for men. The present paper reviews studies on genotoxicity and related endpoints carried out on ETS since the mid-1980s. The evidence from in vitro studies demonstrates induction of DNA strand breaks, formation of DNA adducts, mutagenicity in bacterial assays and cytogenetic effects. In vivo experiments in rodents have shown that exposure to tobacco smoke, whole-body exposure to mainstream smoke (MS), sidestream smoke (SS), or their mixture, causes DNA single strand breaks, aromatic adducts and oxidative damage to DNA, chromosome aberrations and micronuclei. Genotoxicity of transplacental exposure to ETS has also been reported. Review of human biomarker studies conducted among non-smokers with involuntary exposure to tobacco smoke indicates presence of DNA adducts, urinary metabolites of carcinogens, urinary mutagenicity, SCEs and hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene mutations (in newborns exposed through involuntary smoking of the mother). Studies on human lung cancer from smokers and never-smokers involuntarily exposed to tobacco smoke suggest occurrence of similar kinds of genetic alterations in both groups. In conclusion, these overwhelming data are compatible with the current knowledge on the mechanisms of carcinogenesis of tobacco-related cancers, occurring not only in smokers but with a high biological plausibility also in involuntary smokers.

Norppa H
Cytogenetic biomarkers.
IARC Sci Publ. 2004; (157):179-205 [PubMed] Related Publications
Cytogenetic biomarkers in peripheral blood lymphocytes such as chromosomal aberrations, sister chromatid exchanges and micronuclei have long been applied in surveillance of human genotoxic exposure and early effects of genotoxic carcinogens. The use of these biomarker assays is based on the fact that most established human carcinogens are genotoxic in short-term tests and capable of inducing chromosomal damage. The relevance of chromosomal aberrations as a biomarker has been further emphasized by epidemiological studies suggesting that a high frequency of chromosomal aberrations is predictive of an increased risk of cancer. Structural and numerical chromosomal aberrations are typical of cancer cells, probably as a manifestation of genetic instability of such cells, but may also represent mechanisms leading to such instability. The frequency of all three biomarkers increases with age, and this effect is particularly clear for micronuclei in women. Tobacco smoking is known to increase the level of sister chromatid exchanges and chromosomal aberrations, but its effect on micronuclei is unclear. Several studies have recently examined the influence of genetic polymorphisms of xenobiotic metabolizing enzymes on cytogenetic biomarkers. The lack of glutathione S-transferase M1 (GSTM1 null genotype) appears to be associated with increased sensitivity to genotoxicity of tobacco smoking. N-Acetyltransferase (NAT2) slow acetylation genotypes seem to elevate baseline level of chromosomal aberrations, whereas deletion of glutathione S-transferase T1 gene (GSTT1 null genotype) has been found to yield an increase in baseline sister chromatid exchange frequency. These findings may be explained by reduced detoxification capacity rendered by the altered gene and may be linked with exposure to, for example, heterocyclic amines in the case of NAT2 and endogenously formed ethylene oxide in the case of GSTT1. Recently discovered polymorphisms affecting DNA repair may be expected to be of special importance in modulating genotoxic effects, but, as yet, there is very little information about the significance of these polymorphisms or about their impact on cytogenetic biomarkers.

Anttila S, Hakkola J, Tuominen P, et al.
Methylation of cytochrome P4501A1 promoter in the lung is associated with tobacco smoking.
Cancer Res. 2003; 63(24):8623-8 [PubMed] Related Publications
Cytochrome P4501A1 (CYP1A1), which is involved in the metabolic activation of polycyclic aromatic hydrocarbon procarcinogens derived from tobacco smoke, is induced in the lung up to 100-fold because of tobacco smoking. Our aim was to study whether promoter methylation has any role in the smoking-associated expression of CYP1A1 in human lung. Methylation of CpG sites up to 1.4 kb upstream of CYP1A1 gene was studied first by sequencing. Because methylation was observed between nucleotides -1400 and -1000, a methylation-specific single-strand conformational polymorphism method was designed for the region between nucleotides -1411 and -1295 that contains five potential methylation sites, one of them at the xenobiotic responsive element core sequence. Single-strand conformational polymorphism was used on DNA from normal lung samples and peripheral WBCs of smokers and nonsmokers, and on human lung adenocarcinoma (A549) and bronchial epithelial (Beas-2B) cell lines. In lung tissue complete or partial methylation occurred in 33% of heavy smokers (>15 cigarettes/day, n = 30), 71% of light smokers (< or =15 cigarettes/day or quitted 1-7 days earlier, n = 42), and in 98% of nonsmokers (never and ex-smokers, n = 49). Methylation was found to increase in 1-7 days after quitting smoking. In active smokers the lack of methylation in the studied region of CYP1A1 promoter was associated with a slightly higher pulmonary 7-ethoxyresorufin O-deethylase activity in the regression models allowing for the daily tobacco consumption and age. No association was observed in WBC between methylation and tobacco smoking. In lung-derived cell lines the methylation remained stable regardless of induction with benzo(a)pyrene, but a higher induction was observed in Beas-2B cells, which also had less methylation than A549 cells. The association of tobacco smoking with CYP1A1 methylation in the lung suggests that promoter methylation is involved in the regulation of CYP1A1 induction in vivo.

Qiao Y, Ogawa S, Hangaishi A, et al.
Identification of a novel fusion gene, TTL, fused to ETV6 in acute lymphoblastic leukemia with t(12;13)(p13;q14), and its implication in leukemogenesis.
Leukemia. 2003; 17(6):1112-20 [PubMed] Related Publications
ETS variant gene 6 (ETV6)/translocation, ETS, leukemia (TEL)-involving chromosomal translocations are frequently observed in various hematologic neoplasms. We describe here a novel ETV6-involving translocation, t(12;13)(p13;q14), found in the case of acute lymphoblastic leukemia, in which ETV6 fused with a previously unknown gene, named Twelve-thirteen Translocation Leukemia gene (TTL), at 13q14. TTL was weakly but ubiquitously expressed in normal human tissues as detected by reverse transcribed-PCR. Three TTL splicing forms were identified, TTL-T from a human testis cDNA library, with an open-reading frame of 402 bp encoding 133 amino acids (aa), and TTL-B1 and -B2 from a human brain cDNA library. These proteins have no homology to known proteins. In leukemic cells from the patient, both reciprocal fusion transcripts, ETV6/TTL and TTL/ETV6, were expressed. The predominant fusion transcript, TTL/ETV6-1, encodes a predicted 530 aa fusion protein containing 89 aa of the N-terminal TTL fusing to the helix-loop-helix domain and ETS-binding domain of ETV6. Although the function of TTL is yet to be elucidated, our findings will provide another insight into the molecular pathogenesis of leukemia having ETV6-involving translocations.

Piipari R, Nurminen T, Savela K, et al.
Glutathione S-transferases and aromatic DNA adducts in smokers' bronchoalveolar macrophages.
Lung Cancer. 2003; 39(3):265-72 [PubMed] Related Publications
Interindividual differences in the expression of carcinogen-metabolizing enzymes in the lung may modify the effective dose of tobacco carcinogens in this organ. We investigated the role of detoxifying glutathione S-transferases (GST) in the formation of aromatic DNA adducts in bronchoalveolar macrophages (BAM) of active smokers. The effect of GSTs on aromatic DNA adducts was studied separately and in combination with the PAH-metabolizing cytochrome P450 enzyme, CYP3A. GSTA, GSTM3, GSTP, and CYP3A protein levels were analyzed by Western blotting, GSTM1 and GSTP1 genotypes were determined by polymerase chain reaction (PCR) based methods, and numbers of aromatic DNA adducts were measured by nuclease P1 enhanced 32P-postlabeling method in BAM of 31 active smokers. No correlation was observed between GSTA or GSTP proteins or GSTM1 or GSTP1 genotypes and the level of aromatic DNA adducts. A high or medium expression level of GSTM3 was associated with a lower level of aromatic DNA adducts in the smokers who smoked less than 20 cigarettes per day, when the effect of GSTM3 was analyzed in combination with CYP3A (regression analysis; F(6,24)=6.3, P<0.001). No protection by GSTM3 was observed in heavy smokers. High CYP3A levels, on the other hand, increased the number of DNA adducts regardless of the amount of smoking.

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Cite this page: Cotterill SJ. TTL gene, Cancer Genetics Web: http://www.cancer-genetics.org/TTL.htm Accessed:

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