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:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

ABL1 amplification, due to a cryptic episomal translocation NUP214/ABL1, is a novel finding in T-cell acute lymphoblastic leukemia (ALL). Here we report on the incidence and clinical features of this genetic defect in a series of 30 consecutive adult T-cell ALL patients. Multiple copies of the ABL1 gene were detected in two patients (6.6%), one with the karyotype 46,XY,t(1;3)(p36;p21),del(6)(q23)/46,XY and the other without analyzable metaphases. Metaphase/interphase fluorescence in situ hybridization (FISH) detected multiple uncountable signals corresponding to ABL1 in mitotic cells and nuclei from both patients. In one patient, no signals corresponded with the 9p21 chromosomal region, which contains the p16INK4a gene, and in the other one signal was observed. Quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) demonstrated that in these patients ABL1 gene expression was 14- and 18-fold greater than in normal controls, and returned to normal levels only when complete remission was achieved. We reached the following conclusions: (1) FISH is the only technique that promptly identifies T-cell ALL patients with ABL1 amplification, (2) quick identification with FISH is fundamental in the clinic because this T-cell ALL subset is imatinib sensitive but may become resistant due to development of additional mutations, and (3) ABL1 quantitative RT-PCR may be easily applied to monitor minimal residual disease.
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PMID:ABL1 amplification in T-cell acute lymphoblastic leukemia. 1621 63

The unique molecular characteristic of chronic myeloid leukemia (CML), the disease-causing ABL (9q34) to BCR (22q11) translocation, has provided an invaluable tool for disease diagnosis and monitoring of treatment response. The traditional standard in this regard is bone marrow karyotype, also known as conventional cytogenetics (CC), which reveals a shortened chromosome 22, the Philadelphia chromosome, t(9;22)(q34;q11). CC in CML has also been effectively used for monitoring the response to drug therapy. However, this particular laboratory test misses submicroscopic BCR/ABL translocations and is suboptimal for minimal residual disease (MRD) assessment. Both fluorescence in situ hybridization (FISH) and reverse-transcriptase polymerase chain reaction (RT-PCR) feature higher sensitivity in terms of both diagnosis and MRD assessment in CML, compared to CC. Another advantage of these alternative tests is their effective applicability to peripheral blood specimens. The current review highlights the practical literature with respect to the use of FISH for CML whereas the use of RT-PCR has been extensively covered in recent communications.
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PMID:Fluorescent in situ hybridization in the diagnosis, prognosis, and treatment monitoring of chronic myeloid leukemia. 1639 61

Imatinib mesylate (STI571), a specific Bcr-Abl inhibitor, has shown a potent antileukemic activity in clinical studies of chronic myeloid leukemia (CML) patients. Early prediction of response to imatinib cannot be anticipated. We used a standardized quantitative reverse-transcriptase polymerase chain reaction (QRT-PCR) for BCR-ABL transcripts on 191 out of 200 late-chronic phase CML patients enrolled in a phase II clinical trial with imatinib 400 mg/day. Bone marrow samples were collected before treatment, after 12, 20 and at the end of study treatment (52 weeks) while peripheral blood samples were obtained after 2, 3, 6, 10, 14, 20 and 52 weeks of therapy. The amount of BCR-ABL transcript was expressed as the ratio of BCR-ABL to beta2-microglobulin (beta2M). We show that, following initiation of imatinib, the early BCR-ABL level trends in both bone marrow and peripheral blood samples made it possible to predict the subsequent cytogenetic outcome and response. We propose this method as the method of choice for monitoring patients on imatinib therapy. QRT-PCR studies may be able to identify degrees of molecular response that predict both complete cytogenetic response and long term stability, as well as patterns of response that provide an early indication of relapse and imatinib resistance.
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PMID:Prediction of response to imatinib by prospective quantitation of BCR-ABL transcript in late chronic phase chronic myeloid leukemia patients. 1640 13

The Philadelphia chromosome (Ph) as a secondary cytogenetic abnormality is a rare event. It is observed mostly as an additional, late-appearing cytogenetic change during the evolution of acute leukemia and its presentation as a secondary change at the onset of disease is much rarer. We describe here a patient with acute myelogenous leukemia (AML) who had Ph as a secondary chromosome abnormality at diagnosis. Cytogenetic analysis showed an abnormal karyotype, 45,XY,inv(3)(q21q26),-7[4]/45,idem, t(9;22)(q34;q11.2). The p190 variety of BCR-ABL rearrangements was confirmed by a real-time reverse-transcriptase polymerase chain reaction using fluorescent probes. To our knowledge, the minor BCR-ABL fusion gene involving a secondary Ph superimposed on inv(3) and monosomy 7 has not been reported in AML at diagnosis. Along with the identification of more cases, it will be possible to understand the exact role of this secondary Ph in a multistep leukemogenesis.
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PMID:The Philadelphia chromosome as a secondary abnormality in inv(3)(q21q26) acute myeloid leukemia at diagnosis: confirmation of p190 BCR-ABL mRNA by real-time quantitative polymerase chain reaction. 1649 May 99

We have previously reported that both hypotonic stress (HTS) and lysophosphatidic acid (LPA) induce ATP release and a transient reorganization of actin through sequential activation of RhoA/Rho-kinase and focal adhesion kinase F-actin (FAK)/paxillin in human umbilical cord vein endothelial cells (HUVECs). LPA is known to induce the activation of RhoA via its specific receptors, but the mechanisms by which HTS initiates these intracellular signals are not known. The present study aimed to identify the molecule(s) that are unique to the sensing and/or transducing the mechanical stress. Reverse transcriptase-polymerase chain reaction revealed the expression of several integrin subunits in HUVECs. Anti-integrin alpha5beta1 antibody (Ab), but not anti-integrin alpha2, alpha6, alpha v, or beta4 antibodies, inhibited HTS-induced RhoA translocation, tyrosine phosphorylation of FAK and paxillin, ATP release, and actin reorganization. However, the LPA-induced ATP release and actin reorganization were not inhibited by any of these anti-integrin antibodies, indicating that integrin alpha5beta1 plays a pivotal role in the HTS-induced but not in the LPA-induced responses. It is therefore reasonable to assume that this particular subtype of integrin is involved in the initiation of the responses induced by mechanical stimuli in HUVECs.
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PMID:Pivotal role of integrin alpha5beta1 in hypotonic stress-induced responses of human endothelium. 1701 51

Hepatitis C virus (HCV) and hepatitis B virus (HBV) co-infection may differentially influence HIV treatment duration and outcome. This was assessed at The Ottawa Hospital Immunodeficiency Clinic in first-time highly active antiretroviral therapy (HAART) recipients visited between January 2000 and December 2004. Of 968 patients, 526/700 (75%) HIV, 173/230 (75%) HIV-HCV and 30/38 (79%) HIV-HBV-infected patients initiated HAART. Co-infected patients stopped treatment sooner (HBV - 10 months, HCV - 9 months) than HIV mono-infected (17 months) (P<0.001). Injection drug history predicted shorter treatment duration (odds ratio [OR]1.59, P<0.001). Use of non-nucleoside-reverse-transcriptase-inhibitor-containing HAART (OR 0.76, P<0.01) and low-dose ritonavir (<400 mg twice daily)-based HAART (OR 0.83, P = 0.06) predicted longer treatment duration. HCV co-infection did not predict duration of therapy (OR 1.19, P=0.19) once controlled for by these three variables. Poor adherence was a major explanation for eventual treatment interruption in those with HIV-HCV (22% versus 5% in HIV alone; P<0.001) as was substance abuse (7% versus < 1% in HIV; P<0.001). Metabolic complications resulted in HAART interruption in HIV mono-infection (8%) but not with HBV or HCV co-infection (both <1%; P<0.001). Antiretroviral selection is critical to the longevity of initially prescribed regimens, irrespective of viral hepatitis co-infection. Attention to this and strategies targeting substance abuse and adherence in HIV-HCV are predicted to increase the duration of HAART.
Int J STD AIDS 2007 Aug
PMID:Comparison of first antiretroviral treatment duration and outcome in HIV, HIV-HBV and HIV-HCV infection. 1768 17

In Escherichia coli L-arginine is taken up by three periplasmic binding protein-dependent transport systems that are encoded by two genetic loci: the artPIQM-artJ and argT-hisJQMP gene clusters. The transcription of the artJ, artPIQM and hisJQMP genes and operons is repressed by liganded ArgR, whereas argT, encoding the LAO (lysine, arginine, ornithine) periplasmic binding protein, is insensitive to the repressor. Here we characterize the repressible Esigma70 P artJ, P artP and P hisJ promoters and demonstrate that the cognate operators consist of two 18 bp ARG boxes separated by 3 bp. Determination of the energy landscape of the ArgR-operator contacts by missing contact probing and mutant studies indicated that each box of a pair contributes to complex formation in vitro and to the repressibility in vivo, but to a different extent. The organization of the ARG boxes and promoter elements in the control regions of the uptake genes is distinct from that of the arginine biosynthetic genes. The hisJQMP operon is the first member of the E. coli ArgR regulon, directly repressed by liganded ArgR, where none of the core promoter elements overlaps the ARG boxes. Single round in vitro transcription assays and DNase I footprinting experiments indicate that liganded ArgR inhibits P artJ and P artP promoter activity by steric exclusion of the RNA polymerase. In contrast, ArgR-mediated repression of P hisJ by inhibition of RNA polymerase binding appears to occur through topological changes of the promoter region.
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PMID:ArgR-dependent repression of arginine and histidine transport genes in Escherichia coli K-12. 1785 Aug 14

The androgen receptor (AR) is a ligand-activated transcription factor that mediates the actions of the steroid hormones testosterone and dihydrotestosterone at the level of gene transcription. The main transactivation function is modular in structure, maps to the N-terminal domain (NTD), and is termed AF1. This region of the AR is structurally flexible and functions in multiple protein-protein interactions with coregulatory proteins and components of the general transcription machinery. Using surface plasmon resonance, the binding kinetics for the interaction of AR-AF1 with the large subunit of the general transcription factor TFIIF, termed RAP74, and the coactivator SRC-1a were measured. AR-AF1 interacts with both the NTD and CTD of RAP74 and the CTD of SRC-1a. The dissociation constants ( Kd) for the binding of polypeptides derived from RAP74 are in the submicromolar range, while a peptide from SRC-1a bound with a Kd of 14 microM. Significantly, the individual NTD and CTD of RAP74 interacted with AR-AF1 with distinct binding kinetics, with the NTD exhibiting slower on and off rates. TFIIF is involved in transcription initiation and elongation, and the CTD of RAP74 binds to the RNA polymerase II enzyme, the general transcription factor TFIIB, and a CTD phosphatase, FCP1. We have mutated hydrophobic residues in the RAP74-CTD structure to disrupt secondary structure elements and show that binding of AR-AF1 depends upon helix 3 in the winged-helix domain of the RAP74-CTD polypeptide. Altogether, a model is suggested for AR-AF1-dependent transactivation of receptor-target genes.
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PMID:Functional characterization of the native NH2-terminal transactivation domain of the human androgen receptor: binding kinetics for interactions with TFIIF and SRC-1a. 1828 9

After interaction with its receptor, GM-CSF induces phosphorylation of the beta-chain in two distinct domains in macrophages. One induces activation of mitogen-activated protein kinases and the PI3K/Akt pathway, and the other induces JAK2-STAT5. In this study we describe how trichostatin A (TSA), which inhibits deacetylase activity, blocks JAK2-STAT5-dependent gene expression but not the expression of genes that depend on the signal transduction induced by the other domain of the receptor. TSA treatment inhibited the GM-CSF-dependent proliferation of macrophages by interfering with c-myc and cyclin D1 expression. However, M-CSF-dependent proliferation, which requires ERK1/2, was unaffected. Protection from apoptosis, which involves Akt phosphorylation and p21(waf-1) expression, was not modified by TSA. GM-CSF-dependent expression of MHC class II molecules was inhibited because CIITA was not induced. The generation of dendritic cells was also impaired by TSA treatment because of the inhibition of IRF4, IRF2, and RelB expression. TSA mediates its effects by preventing the recruitment of RNA polymerase II to the promoter of STAT5 target genes and by inhibiting their expression. However, this drug did not affect STAT5A or STAT5B phosphorylation or DNA binding. These results in GM-CSF-treated macrophages reveal a relationship between histone deacetylase complexes and STAT5 in the regulation of gene expression.
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PMID:Deacetylase activity is required for STAT5-dependent GM-CSF functional activity in macrophages and differentiation to dendritic cells. 1842 9

The expression of carbonic anhydrase XII (CA12), a gene that encodes a zinc metalloenzyme responsible for acidification of the microenvironment of cancer cells, is highly correlated with estrogen receptor alpha (ER alpha) in human breast tumors. Here, we show that CA12 is robustly regulated by estrogen via ER alpha in breast cancer cells, and that this regulation involves a distal estrogen-responsive enhancer region. Upon the addition of estradiol, ER alpha binds directly to this distal enhancer in vivo, resulting in the recruitment of RNA polymerase II and steroid receptor coactivators SRC-2 and SRC-3, and changes in histone acetylation. Mutagenesis of an imperfect estrogen-responsive element within this enhancer region abolishes estrogen-dependent activity, and chromosome conformation capture and chromatin immunoprecipitation assays show that this distal enhancer communicates with the transcriptional start site of the CA12 gene via intrachromosomal looping upon hormone treatment. This distal enhancer element is observed in the homologous mouse genomic sequence, and the expression of the mouse homologue, Car12, is rapidly and robustly stimulated by estradiol in the mouse uterus in vivo, suggesting that the ER regulation of CA12 is mechanistically and evolutionarily conserved. Our findings highlight the crucial role of ER in the regulation of the CA12 gene, and provide insight into the transcriptional regulatory mechanism that accounts for the strong association of CA12 and ER in human breast cancers.
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PMID:Estrogen receptor regulation of carbonic anhydrase XII through a distal enhancer in breast cancer. 1845 Nov 79


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