Identification of a putative RNA helicase in<i>E.coli</i>

Iggo, R.; Picksley, Steven M.; Southgate, Jennifer; McPheat, Jane; Lane, David P.

doi:10.1093/nar/18.18.5413

Cited by 42 publications

(22 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…36 The protein encoded by the HAGE gene seems to be a new member of the family of DEAD-box proteins, 37 which contain the highly conserved Asp-GluAla-Asp (D-E-A-D) motif. These proteins are involved in many aspects of RNA metabolism, spermatogenesis, embryogenesis, and cell growth, functioning as important transcriptional regulators.…”

mentioning

confidence: 99%

Epigenetic regulation of human cancer/testis antigen gene, HAGE, in chronic myeloid leukemia

Román‐Gómez

Jiménez-Velasco²,

Agirre³

et al. 2007

Haematologica

View full text Add to dashboard Cite

Background and ObjectivesCancer testis antigens (CTA) provide attractive targets for cancer-specific immunotherapy. Although CTA genes are expressed in some normal tissues, such as the testis, this immunologically protected site lacks MHC I expression and as such, does not present self antigens to T cells. To date, CTA genes have been shown to be expressed in a range of solid tumors via demethylation of their promoter CpG islands, but rarely in chronic myeloid leukemia (CML) or other hematologic malignancies. Design and MethodsIn this study, the methylation status of the HAGE CTA gene promoter was analyzed by quantitative methylation-specific polymerase chain reaction (MSP) and sequencing in four Philadelphia-positive cell lines (TCC-S, K562, KU812 and KYO-1) and in CML samples taken from patients in chronic phase (CP n=215) or blast crisis (BC n=47). HAGE expression was assessed by quantitative reverse transcriptase-polymerase chain reaction. ResultsThe TCC-S cell line showed demethylation of HAGE that was associated with overexpression of this gene. HAGE hypomethylation was significantly more frequent in BC (46%) than in CP (22%) (p=0.01) and was correlated with high expression levels of HAGE transcripts (p<0.0001). Of note, in CP-CML, extensive HAGE hypomethylation was associated with poorer prognosis in terms of cytogenetic response to interferon (p=0.01) or imatinib (p=0.01), molecular response to imatinib (p=0.003) and progression-free survival (p=0.05). Interpretations and ConclusionThe methylation status of the HAGE promoter directly correlates with its expression in both CML cell lines and patients and is associated with advanced disease and poor outcome. (p210), which has abnormal tyrosine-kinase activity that is central to the pathogenesis of the disease.1 Treatment of CML has been notably improved by imatinib mesylate, a potent tyrosinekinase inhibitor that blocks the kinase activity of p210, thus inhibiting proliferation of Ph'-positive progenitors. 2In the past 5 years, the results of imatinib treatment of CML have established this drug as the first-line therapy for CML patients.3 However, both the persistence of molecular disease in most imatinib-treated patients, as well as the observation that discontinuation of the drug usually results in a rapid loss of the response, indicate that it is unlikely that imatinib alone can cure CML. 2,3An alternative attempt to target CML cells is an active, specific immunotherapy (e.g. a vaccine). In fact, because of the unique amino acid sequence of p210 at the fusion point, the protein is a tumor-specific antigen to which an immune response can be induced. In some studies it has been shown that peptides derived from the p210 fusion point (b3a2) can bind to several HLA class I and class II molecules and thus generate peptidespecific dendritic cells (DC) and cytotoxic T lymphocyte (CTL) responses in vitro. 4,5 Preliminary clinical data suggest that the addition of a b3a2-specific vaccine to b3a2-CML patients treated with conventional treatment might favor a furt...

show abstract

mentioning

confidence: 99%

Epigenetic regulation of human cancer/testis antigen gene, HAGE, in chronic myeloid leukemia

Román‐Gómez

Jiménez-Velasco²,

Agirre³

et al. 2007

Haematologica

View full text Add to dashboard Cite

show abstract

“…Two E. coli helicases, DbpA (36,37), involved in ribosome maturation, and RhlB (38), a subunit of the E. coli RNA degradosome, have been shown to possess RNA-RNA unwinding activity. The genes hepA (39), hrpA and rhpB (40), rhlE (41), phoH and yjhR (42), lhr (43), yejH (34), srmB (44), b1808 (34) and deaD (45) have been predicted to encode DNA and RNA helicases, but the corresponding proteins have never been purified, and their helicase activities have yet to be demonstrated. DinG and UvrD are the only E. coli helicases induced by DNA damage.…”

Section: Overexpression and Deletion Of Ding Do Notmentioning

confidence: 99%

Characterization of the DNA Damage-inducible Helicase DinG from Escherichia coli

Voloshin

Vanevski

Khil

et al. 2003

Journal of Biological Chemistry

102

View full text Add to dashboard Cite

dinG was identified as a DNA damage-inducible gene in a genetic screen scoring for induction of the transcription of galactokinase gene fusions after treatment of Escherichia coli cells with mitomycin C. Transcription of the dinG::galK fusion was suppressed by overexpression of the LexA protein, suggesting the SOS nature of the induction (1). Indeed, sequencing of the dinG promoter revealed an asymmetric nucleotide sequence TTG(N 10 )CAG that was similar but not identical to the canonical, fully symmetrical CTG(N 10 )CAG SOS box. Despite the deviation of the SOS box found in the dinG regulatory region from the consensus sequence of the LexA-binding box, the double-stranded (ds) 1 oligonucleotide TTGG(N 8 )ACAG bound the LexA repressor with high affinity in an electrophoretic mobility shift assay (2). The dinG promoter was also up-regulated upon DNA damage by nalidixic acid (3).dinG, along with lexA and dinI, was isolated in another genetic screen aimed at isolating multicopy suppressors of the cold-sensitive phenotype of the DinD68 mutation. This particular mutation in the DNA damage-inducible dinD gene, which is also regulated by the LexA-RecA system, results in the constitutive expression of the SOS response at lowered temperature (Ͻ20°C) (4). Because both dinG and dinI are part of the SOS response (1, 2, 5) and they suppress an SOS phenotype of the dinD68 mutation (6), dinG could also be a negative regulator of the SOS response in a manner similar to dinI (7,8).Analysis of the protein sequence of E. coli dinG reveals that it encodes a putative DNA helicase related to yeast DNA helicases Chl1 and Rad3 from Saccharomyces cerevisiae, Rad15 from Schizosaccharomyces pombe, and the human helicases XPD and BACH1 (9, 10). The mutant forms of the last two proteins result in well described human diseases, three human recessive photosensitive syndromes for XPD, and early onset breast cancer for BACH1 (10, 11). DinG and its eukaryotic counterparts have been classified as superfamily II helicases on the basis of the presence of seven canonical helicase motifs in their sequences (9,12,13). Still, the presence of the helicasespecific motifs in the protein amino acid sequence per se does not necessarily imply that it is a bona fide helicase. Proteins having helicase motifs but lacking a helicase activity are well known. Among them are the endonuclease (R) subunits of type I and type III restriction-modification enzymes (14), both bacterial and human transcription-repair coupling factors Mfd (15), and CSB/ERCC6 (16), members of SWI2/SNF2 family chromatin remodeling factors (17) and the RAD54 recombinational DNA repair protein (18).To prove that DinG is a true helicase, we carried out the purification and biochemical characterization of the E. coli DinG protein. In agreement with the prediction (9), DinG possesses DNA-dependent ATPase and helicase activities. We discuss the possible biological role that DinG helicase might play. EXPERIMENTAL PROCEDURESBacterial Strains and Plasmids-Gene deletions were created using a combinati...

show abstract

“…A gene cloned by hybridization with an S. pombe dbp2 DNA probe is the E. coli dbpA gene (Iggo et al, 1990). Overexpression of the DbpA protein resulted in no phenotype, although this gene is normally expressed at low levels.…”

Section: The P68 Groupmentioning

confidence: 99%

D‐E‐A‐D protein family of putative RNA helicases

Schmid

Linder

1992

Molecular Microbiology

495

366

View full text Add to dashboard Cite

Summary RNA metabolism plays a central role in cell growth. It is essential to regulate RNA synthesis, processing, stability and degradation. Conformational changes in RNA are key elements in regulating cellular processes. Recently, an increasing number of putative RNA helicases from different organisms ranging from Escherichia coli to humans and viruses have been identified. They are Involved in diverse cellular functions such as RNA splicing, ribosome assembly, initiation of translation, spermatogenesis, embryogenesis, and cell growth and division. Based on sequence homologies these proteins were grouped in a family, the D‐E‐A‐D box protein family (D‐E‐A‐D = Asp‐Glu‐Ala‐Asp). Some of the better characterized members have been shown to possess ATP‐binding and hydrolysing activities as well as ATP‐dependent RNA helicase activities. Most of the genes encoding such proteins have been isolated from yeast, on which we will focus in this review. From sequence data, three of the members form a subfamily, the D‐E‐A‐H subfamily.

show abstract

Identification of a putative RNA helicase inE.coli

Cited by 42 publications

References 21 publications

Epigenetic regulation of human cancer/testis antigen gene, HAGE, in chronic myeloid leukemia

Epigenetic regulation of human cancer/testis antigen gene, HAGE, in chronic myeloid leukemia

Characterization of the DNA Damage-inducible Helicase DinG from Escherichia coli

D‐E‐A‐D protein family of putative RNA helicases

Contact Info

Product

Resources

About