Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.5.1.2 (DNA ligase)
 2,749 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A rapid and sensitive technique is described that measures the length of the poly(A) tail on a specific mRNA within subnanogram quantities of total cellular RNA [the Poly(A) test (PAT)]. In a single-tube reaction, a poly(dT) primer is synthesized in situ on the poly(A) tail of mRNAs using oligo(dT) and DNA ligase. By modulating the annealing temperature and primer concentrations, a GC-rich adapter sequence is targeted to the 5' end of the poly(dT) primer. This ligated poly(dT)-anchor is then used to prime reverse transcription of the mRNA, yielding a library of PAT cDNAs. The length of a poly(A) tail is determined by PCR amplification using the oligo(dT)-anchor primer and a message-specific primer. Comparison of PCR products from different samples allows quantitative determination of changes in polyadenylation of a given mRNA. This technique overcomes many of the pitfalls associated with conventional poly(A) tail length assessments and should prove useful in studying a variety of processes relating to polyadenylation.
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PMID:Rapid and sensitive analysis of mRNA polyadenylation states by PCR. 758 Sep 23

Anti-tumour activity of triazene compounds of clinical interest [i.e. dacarbazine and temozolomide (TMZ)] relies mainly on the generation of methyl adducts to purine bases of DNA. Two DNA repair enzyme systems, i.e. the O6-guanine-alkyl-transferase (MGMT) and mismatch repair (MMR), play a predominant role in conditioning the cytotoxic effects of triazenes. In particular, high levels of MGMT associated with target cells are responsible of resistance to triazenes. On the contrary, the presence of MMR is required for the cytotoxic effects of these compounds. Previous studies performed by our group and a more recent clinical investigation reported by Karen Seiter, pointed out that triazene compounds could play an important role in the treatment of refractory acute leukaemia. Leukaemia blasts, especially of lymphoblastic leukaemia, show frequently high levels of MGMT activity. Therefore, it reasonable to hypothesize that combined treatment of leukaemia patients with triazene compounds along with MGMT inhibitors could lead to a better control of the disease. PaTrin-2 (O6-(4-bromothenyl)guanine, PAT) is a potent and scarcely toxic MGMT inhibitor recently introduced in clinical trials. This drug is used in combination with triazene compounds in order to augment their anti-tumour efficacy against neoplastic cells endowed with high MGMT activity. The present report describes, for the first time, pre-clinical in vitro studies on the cytotoxic activity of combined treatment with PAT+TMZ against long-term cultured leukaemia cells and primary leukaemia blasts obtained from patients with acute lymphoblastic leukaemia or acute myeloblastic leukaemia. The results point out that, both in long-term cultured leukaemia cell lines and in primary blast samples, PAT could improve dramatically the sensitivity of malignant cells to the cytotoxic effects of TMZ. This sensitizing effect is detectable when leukaemia cells show resistance mechanisms based on a MGMT-proficient phenotype. On the contrary, when resistance to TMZ is dependent on MMR deficiency, no influence of PAT can be detected in various experimental conditions. In conclusion, these results appear to provide disease-oriented rational basis to design novel clinical protocols for the treatment of acute leukaemia with combined administration of PAT and triazene compounds.
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PMID:O6-(4-bromothenyl)guanine (PaTrin-2), a novel inhibitor of O6-alkylguanine DNA alkyl-transferase, increases the inhibitory activity of temozolomide against human acute leukaemia cells in vitro. 1641 62