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:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tal-1 rearrangements are associated with nearly 30% of human T acute lymphoblastic leukemia. Tal-1 gene encodes a putative transcription factor with a basic helix-loop-helix domain and is known to be predominantly expressed in hematopoietic cells. We investigated the pattern of tal-1 expression in purified human hematopoietic cells by in situ hybridization and reverse transcriptase polymerase chain reaction analysis. Both methods demonstrated that the tal-1 gene is expressed in megakaryocytes and erythroblasts as well as in basophilic granulocytes. In addition, our results indicate that the tal-1 1A promoter, which contains two consensus GATA-binding sites, is active mainly in these lineages. Because the GATA-1 gene is known to transactivate several genes specific for the erythroid, megakaryocytic, and mastocytic/basophilic lineages, we studied GATA-1 expression in these purified hematopoietic cells. We found that GATA-1 and tal-1 genes are coexpressed in these three lineages. Remarkably, the expression of both genes is downmodulated during erythroid and megakaryocytic terminal maturation. In immature hematopoietic cells, tal-1 and GATA-1 genes are coexpressed in committed progenitors cells (CD34+/CD38(2+)), whereas they are not detectable in the most primitive cells (CD34(2+)/CD38-). In contrast, GATA-2 is strongly expressed in both most primitive and committed progenitors cells, whereas GATA-3 is mostly detected in most primitive ones. Altogether our results strongly suggest that GATA-1 modulates the transcription of tal-1 during the differentiation of the erythroid, megakaryocytic, and basosophilic lineages.
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PMID:Expression of tal-1 and GATA-binding proteins during human hematopoiesis. 767 94

Differential display in combination with arbitrarily primed polymerase chain reaction (PCR) fingerprinting has become one of the most powerful techniques to identify and isolate mRNAs that are differentially expressed in pairs of biological samples. However, in many cases the cDNA band corresponding to the differentially amplified product contains several cDNA species that comigrate with the cDNA of interest due to the poor resolution of the fingerprinting gels, thus hampering further analysis and identification of the desirable cDNA. To improve the electrophoretic resolution of differentially amplified cDNAs, we have utilized Resolver Gold agarose gel electrophoresis (Ingenius) as an additional step to overcome downstream problems encountered during RNA fingerprinting experiments. To illustrate the power of the modified differential display procedure we present a detailed analysis of the cDNA products differentially displayed in tumor biopsies obtained from a noninvasive (grade II, Ta) and an invasive (grade III, T2-T4) human bladder transitional cell carcinoma (TCC). Several genes that were differentially expressed in this tumor pair were identified. These included: tropomyosin 4, the protein disulfide isomerase precursor (PDI), MRP14, signal transducer CD24, keratins 8 and 13, cytochrome oxidase subunit IV (COXIV), putative transcription factor HOX-1.3, as well as two novel genes of yet unknown function. All of the identified cDNAs were shown to be truly differentially expressed by Northern blotting, reverse transcriptase-PCR (RT-PCR), and two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) analysis of the corresponding lesions.
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PMID:Identification of true differentially expressed mRNAs in a pair of human bladder transitional cell carcinomas using an improved differential display procedure. 1019 29

The t(10;11)(p13-14;q14-21) is a rare but recurring translocation associated with acute lymphoblastic leukaemia (ALL) and acute myeloid leukaemia (AML). Recently the CALM gene was cloned from the t(10;11) breakpoint of U937 and fused to AF10, a putative transcription factor, which had been identified as one of the fusion partners of the MLL gene. In order to define the involvement of these genes in primary leukaemias and cell lines with t(10;11), we analysed the expression of fusion transcripts by reverse transcriptase-polymerase chain reaction (RT-PCR) in five patient samples including ALL, AML and lymphoblastic lymphoma, and three monocytic cell lines (P31/Fujioka, KP-Mo-TS and U937). The CALM-AF10 fusion transcript was detected in all samples; however, the AF10-CALM fusion was not detected in two patient samples and one cell line. In RT-PCR analysis there were six isoforms of the CALM-AF10 fusion transcripts and five of AF10-CALM fusion transcripts. We also detected novel transcripts in U937. Sequence analysis revealed that all these isoforms had in-frame junctions and that some of them resulted from alternative splicing at different exons of CALM and others from different breakpoints at CALM and/or AF10. There were at least two different breakpoints of CALM and three of AF10 gene. Our results suggest that the CALM-AF10 fusion gene is a constant feature and is involved in the pathogenesis of haematological malignancies with t(10;11)(p13-14;q14-21), showing various and often multilineage phenotypes. Thus, t(10;11) needs to be investigated by RT-PCR for identification of the genes involved.
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PMID:Consistent detection of CALM-AF10 chimaeric transcripts in haematological malignancies with t(10;11)(p13;q14) and identification of novel transcripts. 1055 2

Primary amyloidosis is a fatal disorder characterized by low numbers of clonal plasma cells in the bone marrow and the systemic deposition of light chain fragments in the form of amyloid. The molecular pathobiology of amyloidosis is primarily unknown. Recently, a novel karyotypically undetectable t(4;14)(p16.3;q32) translocation has been identified in approximately 20% of multiple myeloma patients. The translocation leads to the apparent deregulation of two genes located on 4p16.3, the fibroblast growth-factor receptor 3 (FGFR3), and the putative transcription factor multiple myeloma SET domain (MMSET), and to the generation of IGH/MMSET hybrid transcripts. In this study, we investigated the presence of the t(4;14) translocation in 42 AL patients using a reverse transcriptase-polymerase chain reaction assay for the detection of IGH/MMSET transcripts. Chimeric transcripts were found in six patients (14%) and were consistent with a 4p16.3 breakpoint involving intron 3 and juxtaposing IGH regions to exon 4. In three of these cases, hybrid transcripts juxtaposing IGH regions to exon 5 were also observed and were probably the result of an alternative splicing skipping exon 4. Because all of the fusion transcripts (six of six) excluded exon 3, the first translated MMSET exon, only putative 5' truncated MMSET proteins could be generated. In conclusion, our results demonstrate that the t(4;14)(p16.3;q32) translocation is a recurrent genetic lesion in primary amyloidosis.
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PMID:Translocation T(4;14)(p16.3;q32) is a recurrent genetic lesion in primary amyloidosis. 1133 57

The t(10;11)(p13;q14-21) is a non-random translocation described in acute lymphoblastic and myeloid leukaemias. It results in the fusion of the gene CALM, which encodes a clathrin assembly protein, on 11q14 to the gene AF10, a putative transcription factor on 10p13. Here we describe for the first time, the occurrence of a CALM-AF10 fusion in a case of acute megakaryoblastic leukaemia. Fluorescence in situ hybridisation and reverse transcriptase polymerase chain reaction were used to confirm the presence of a CALM-AF10 fusion. A novel splice variant of CALM missing nt 1927-2091 was also detected. Though CALM is a cytoplasmic protein, the chimaeric fusion product is able to localise to both the nucleus and cytoplasm. Analysis of the fusion variants suggests, however, that the critical fusion product is likely to be cytoplasmic and contain the interactive leucine zipper of AF10.
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PMID:Identification and molecular characterisation of a CALM-AF10 fusion in acute megakaryoblastic leukaemia. 1141 76

Estrogenic steroid hormones mediate complex actions important in both embryonic and adult life. The hormones signal through ligand-inducible transcription factors known as estrogen receptors (ERs). In this study, we have isolated a zebrafish estrogen receptor with homology to human estrogen receptor beta (ERbeta). This zebrafish ERbeta (ERbetaa) has a conserved genomic structure of eight coding exons with boundaries similar to those of human ERbeta. The coding exon structures of two other zebrafish estrogen receptors (ERalpha and ERbetab) are presented as well. We also analyzed 3.3 kb of the promoter region and identified numerous putative transcription factor binding sites, including SP1 and ER half sites. Zebrafish ERbetaa message RNA is maternally loaded, but quickly degraded after fertilization, as detected by reverse transcriptase polymerase chain reaction. ERbetaa transcripts are detected again between 24 and 48 h post fertilization. These results indicate that ERbeta has been highly conserved during evolution and is likely used during later embryogenesis in zebrafish. Future identification of the expression levels and patterns of this and other estrogen receptors in zebrafish will allow a better understanding of estrogen signaling during embryogenesis.
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PMID:Genomic structure and embryonic expression of estrogen receptor beta a (ERbetaa) in zebrafish (Danio rerio). 1245 62

Recent studies have indicated that ghrelin stimulates growth hormone release from the pituitary via the growth hormone secretagogue receptor (GHSR). We have previously isolated two GHSR subtypes from the pituitary of the black seabream Acanthopagrus schlegeli. In the present study, we have cloned and characterized ghrelin from the same fish species at both the cDNA and gene levels. The full-length seabream ghrelin cDNA, isolated from sea-bream stomach using a novel approach by exploiting a single conserved region in the coding region, was found to encode a prepropeptide of 107 amino acids, with the predicted mature ghrelin peptide consisting of 20 amino acids (GSSFLSPSQKPQNRGKSSRV). Embedded in this full-length cDNA is a putative fish orthologue of the recently reported mammalian obestatin peptide. The ghrelin gene in black seabream, obtained by genomic PCR, was found to encompass four exons and three introns, possessing the same structural organization as in tilapia and goldfish, but different from that in rainbow trout. In addition, a 2230-bp 5'-flanking region of the seabream ghrelin gene was obtained by genome walking. Sequence analysis revealed that, as in the case of the human ghrelin gene, there is neither a GC box nor a CAAT box present in the isolated 5'-flanking region. However, a number of putative transcription factor-binding sites different from the human counterpart were found in the 5'-flanking region of the seabream ghrelin gene, suggesting that different cis- and trans-acting elements are involved in controlling their gene expression. Functional activity of this 5'-flanking region was examined by cloning it into the pGL3-Basic vector upstream of the luciferase reporter gene and transfected into various cell lines. Positive promoter activity could only be recorded in the colon-derived Caco-2 cells, suggesting that the cloned 5'-flanking region represents the functional promoter of the seabream ghrelin gene, which exhibits tissue-specific promoter activity. Using reverse transcriptase PCR analysis, expression of ghrelin was detected only in the seabream stomach, but not in the other tissues examined, including the brain, gill, intestine, kidney, liver and spleen. This stomach-specific expression of ghrelin in seabream is subject to regulation, as administration of growth hormone or ipamorelin to the fish in vivo was demonstrated to enhance its expression. Reminiscent of the homologous upregulation found in the transcriptional control of the seabream GHSR gene, a similar homologous regulatory mechanism might also exist in controlling the expression of seabream ghrelin. The identification of both GHSR and ghrelin from a single fish species would facilitate our subsequent studies on the elucidation of the physiological functions of the ghrelin/GHSR system in teleost. The possible existence of obestatin in teleost opens up new research avenues on the somatotropic axis in fish.
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PMID:Seabream ghrelin: cDNA cloning, genomic organization and promoter studies. 1664 3

Superoxide dismutases are an ubiquitous family of enzymes that function to efficiently catalyze the dismutation of superoxide anions. Two unique and highly compartmentalized bay scallop Argopecten irradians superoxide dismutases: MnSOD and ecCuZnSOD, have been molecularly characterized in our previous study. To complete characterize the SOD family in A. irradians, a novel intracellular copper/zinc SOD from the A. irradians (Ai-icCuZnSOD) was obtained and characterized. The full-length cDNA of Ai-icCuZnSOD was 1047 bp with a 459 bp open reading frame encoding 152 amino acids. The genomic length of the Ai-icCuZnSOD gene was about 4279 bp containing 4 exons and 3 introns. The promoter region containing many putative transcription factor binding sites were analyzed. Furthermore, quantitative reverse transcriptase real-time PCR (qRT-PCR) analysis indicated that the highest expression of the Ai-icCuZnSOD was detected in gill and the expression profiles in hemocytes of bay scallops challenged with bacteria Vibrio anguillarum and lipopolysaccharide (LPS) were different. The result presented an increased expression after injection with LPS whereas no significant changes were observed after V. anguillarum injection. A fusion protein containing Ai-icCuZnSOD was produced in vitro. The rAi-icCuZnSOD is a stable enzyme, retaining more than 80% of its activity between 10 and 60 degrees C and keeping above 88% of its activity at pH values between 5.8 and 9. Ai-icCuZnSOD is more stable under alkaline than acidic conditions.
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PMID:Intracellular copper/zinc superoxide dismutase from bay scallop Argopecten irradians: its gene structure, mRNA expression and recombinant protein. 1942 8

Telomeres are regions of repeated DNA sequence that cap the ends of eukaryotic chromosomes. They act as disposable safeguards to prevent the loss of important genetic information during DNA replication due to the inability of DNA polymerase to replicate DNA to the ends of linear chromosomes. The synthesis of new telomeric repeats using an RNA molecule as a template is catalyzed by the enzyme telomerase. In embryonic stem cells, the gene encoding the catalytic protein subunit of the telomerase complex (telomere reverse transcriptase [TERT]) is transcriptionally active and critical for telomere elongation, allowing for continued cellular differentiation during development. The TERT gene is down-regulated as embryogenesis progresses to limit the proliferative capacity of cells. As a result, in normal human adult somatic cells the TERT gene is silenced. However, in over 90% of cancers, the TERT gene is reactivated, allowing cells to bypass senescence and become immortalized. In this study, we explore the molecular mechanisms that regulate transcriptional expression of the TERT gene. Bioinformatic analysis of the noncoding genomic regions around the human TERT gene identified a TERT ultra-conserved (TUC) module located 5 kb upstream of the transcription start site. This 308 bp region is over 75% conserved between distantly related mammalian species and over 91% conserved among primate species. The cis-regulatory potential of the TUC region was tested in cell-based reporter gene assays. Transient transfections into HeLa and lung fibroblast cells demonstrated that the TUC module has transcriptional enhancer activity. Further bioinformatic analysis revealed that the TUC region is highly enriched in putative transcription factor binding sites for proteins involved during hematopoiesis, indicating that the TUC module may be an enhancer for the TERT gene in specific cell lineages.
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PMID:Characterization of an ultra-conserved putative cis-regulatory module at the mammalian telomerase reverse transcriptase gene. 2043 56

Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine produced by many mammalian tissues. It is also found in ticks and may function to aid the tick in regulating host responses to tick feeding. Our hypothesis is that MIF functions in tick blood meal acquisition and pathogen transmission. This study was performed to understand the expression and regulation of MIF in the American dog tick, Dermacentor variabilis during early stages of blood feeding. We used quantitative reverse transcriptase PCR to study the gene expression during the first 96 h of feeding. Increases in MIF gene expression were observed in salivary gland and midgut tissues during the first 6 days of feeding. RNAi-mediated gene knockdown of D. variabilis MIF was demonstrated but we did not observe measureable phenotypic impact on blood meal acquisition in female ticks. These observations are consistent with previously published data on the lone star tick Amblyomma americanum and suggest that MIF may not have a direct impact on tick blood meal acquisition. Silencing of subolesin, a putative transcription factor, down-regulated MIF expression by 50 %.
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PMID:Expression and regulation of macrophage migration inhibitory factor (MIF) in feeding American dog ticks, Dermacentor variabilis. 2247 44


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