Amplification of a DEAD box protein gene in retinoblastoma cell lines.

Godbout, Roseline; Squire, Jeremy A.

doi:10.1073/pnas.90.16.7578

Cited by 92 publications

(86 citation statements)

References 41 publications

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“…This result is in good agreement with that reported by Squire et al [9]. Since DDX1 is preferably expressed in fetal retina, brain and spinal cord and possibly plays an essential role in the ceils of neuroectodermal origin [14], it is reasonable to consider that the constitutive expression of DDX1 in neuroblastomas, which are of neural crest origin, could be essential for their growth. Our understanding based on the present work, therefore, suggests that there is the basal and/or constitutive expression of DDX1 essential for the growth of neuroblastomas despite its amplification status and that the high expression in the amplified cell lines could, therefore, correspond simply to the copy number of the amplified DDX1, rather than to transcriptional alteration for tumorigenesis.…”

Section: Discussionsupporting

confidence: 81%

“…Therefore, it is of interest to know whether DDX1 contributes to tumorigenesis in cooperation with MYCN. DDX1 protein, which belongs to the DEAD box protein family [14], is characterized by the conserved D(Asp)-E(Glu)-A(Ala)-D(Asp) (DEAD) motif and is a putative RNA helicase with RNA-dependent ATPase activity [15][16][17][18]. Functionally, it has been implicated in translational initiation, ribosomal assembly, and RNA splicing in relation to spermatogenesis, embryogenesis, and/or cell growth and division [19].…”

Section: Introductionmentioning

confidence: 99%

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Expression of two dead box gene (DDX1 amd DDX6) is independent of that of MYCN in human neuroblastoma cell lines

Akiyama

Akao²,

Yokoyama

et al. 1999

IUBMB Life

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Summary. To examine whether two DEAD box genes, DDX1 and DDX6, would have some roles in the progression of tumors, we investigated the correlation of the expression of these genes with that of MYCN in neuroblastomas either with or without MYCN amplification. The mRNA of MYCN was observed only in the cell lines with amplification of MYCN. The mRNAs of DDX1 and DDX6 were found in all the cell lines examined, but the correlation between the mRNA levels of DDX1 or DDX6 and MYCN was poor. These findings suggest that the expression of neither DEAD box gene is correlated with the gene expression of MYCN.

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Section: Discussionsupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Expression of two dead box gene (DDX1 amd DDX6) is independent of that of MYCN in human neuroblastoma cell lines

Akiyama

Akao²,

Yokoyama

et al. 1999

IUBMB Life

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“…For instance, Rck/p54 is overexpressed in neuroblastoma, glioblastoma, rhabdomyosarcoma and lung cancer cells as well as in colorectal tumors (Akao et al, 1995;Nakagawa et al, 1999). Further, the DDX1 RNA helicase gene is often coamplified with N-myc in retinoblastomas and neuroblastomas and its co-amplification correlates with a poorer prognosis (Godbout and Squire, 1993;Squire et al, 1995;George et al, 1996). CREB-binding protein (CBP) and p300 are paralogous coactivators of transcription.…”

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confidence: 99%

Synergism between p68 RNA helicase and the transcriptional coactivators CBP and p300

2003

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p68 RNA helicase has been implicated in a variety of processes, including rearrangement of RNA secondary structures, RNA splicing, gene transcription and tumor development, yet its mechanisms of action are not well understood. In this study, we show that p68 is predominantly localized to the cell nucleus, where it partially colocalizes with the transcriptional coactivator p300. Accordingly, p68 and p300, or the paralogous CREBbinding protein (CBP), coimmunoprecipitate. Similarly, p68 and RNA polymerase II (Pol II) are able to interact in vivo. GST pull-down assays confirmed these interactions in vitro, demonstrating that p68 can interact with several domains of CBP, while CBP/p300 bind to amino acids 176-388 of p68 and RNA Pol II binds to the N-terminal 80 amino acids of p68. Furthermore, p68 stimulates transcription mediated by the C-terminal transactivation domain of CBP. p68 is also able to stimulate TPA oncogene responsive unit (TORU) promoter activity, and p300 acts in synergy with p68. On the other hand, suppression of CBP/p300 function by the adenoviral protein E1A abolishes TORU promoter activation by p68. Altogether, our results suggest the existence of a multiprotein complex in which p68 RNA helicase, CBP/p300 and RNA Pol II jointly promote gene expression.

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“…One of them was DDX1. DDX1 (originally named HuDBP-RB for human DEAD box protein identified in retinoblastoma cells) was isolated from a screen for cDNA clones of transcripts preferentially expressed in the retinoblastoma cell lines (24). Co-amplification of DDX1 and the proto-oncogene MYCN has been demonstrated in both retinoblastoma and neuroblastoma cell lines (24,25).…”

mentioning

confidence: 99%

“…DDX1 (originally named HuDBP-RB for human DEAD box protein identified in retinoblastoma cells) was isolated from a screen for cDNA clones of transcripts preferentially expressed in the retinoblastoma cell lines (24). Co-amplification of DDX1 and the proto-oncogene MYCN has been demonstrated in both retinoblastoma and neuroblastoma cell lines (24,25). DDX1 protein levels in MYCN/DDX1-amplified neuroblastoma and retinoblastoma cell lines correlate well with DDX1 gene copy number and its transcript levels (26).…”

mentioning

confidence: 99%

An RNA Helicase, DDX1, Interacting with Poly(A) RNA and Heterogeneous Nuclear Ribonucleoprotein K

Chen

Lin

Tsay

et al. 2002

Journal of Biological Chemistry

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Heterogeneous nuclear ribonucleoprotein K (hnRNP K) is a multifunctional protein known to be involved in the regulation of transcription, translation, nuclear transport, and signal transduction. To systematically obtain insight into mechanisms of hnRNP K activities, we set out to identify protein factors that interact with hnRNP K by using glutathione S-transferase-hnRNP K affinity chromatography followed by liquid chromatography/mass spectrometry/mass spectrometry analysis. Several partner proteins in the K562 cell lysates were identified through this method. One of them is a DEAD box-containing putative RNA helicase, DDX1. In vitro binding and co-immunoprecipitation studies confirmed the protein-protein interaction between hnRNP K with DDX1, and the region spanning amino acids 1-276 of hnRNP K is apparently responsible for its physical interaction with DDX1. Interestingly, their interaction was disrupted by the addition of poly(C), poly(A), and poly(U) RNA substrates. We found that DDX1 was a homopolymeric poly(A) RNA-binding protein. On the other hand, the ATPase activity of the purified recombinant DDX1 protein was stimulated by these homopolymeric RNAs and yeast total RNA but not by DNA. Moreover, the immunoprecipitated DDX1 complex but not purified DDX1 can unwind double-stranded RNA having singlestranded poly(A) overhangs.The hnRNP K 1 protein has been identified as a component of the heterogeneous nuclear ribonucleoprotein complexes. These hnRNP proteins bind pre-mRNAs directly and appear to facilitate various stages of mRNA biogenesis (1-3). hnRNP K can bind to RNA and single-stranded or double-stranded DNA. The nucleic acid binding activity of hnRNP K is mediated by three repeats of motifs termed the K homology domain, which consists of 65-70 residues (4). It contains both classical nuclear localization signal and the K nuclear shuttling domain that allow the protein to shuttle between nucleus and cytoplasm (5). hnRNP K appears to be involved in transcriptional regulation as exemplified by its binding to a C-rich sequence (the CT element) within the human c-myc promoter and subsequent activation of c-myc expression (6 -8). Additionally, its association with CCAAT/enhancer-binding protein ␤ results in the repression of CCAAT/enhancer-binding protein ␤ target genes (9). hnRNP K was also reported to bind 3Ј end of 15-lipoxygenase, and HPV 16 L2 mRNA was reported to trigger translation inhibition (10, 11). Moreover, direct protein-protein interactions between hnRNP K and some proto-oncogene products serve as clear evidence that hnRNP K acts as a docking platform to facilitate molecular interactions within signal transduction cascades (12-16).Modulation of RNA structure is an essential step in many fundamental cellular processes, including RNA synthesis, splicing, export, turnover, and translation. Recently, an increasing number of RNA helicases from different organisms, ranging from bacteria to yeast, human, and virus, has been identified (17, 18). DEAD box proteins are a family of putative RNA helicases t...

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Amplification of a DEAD box protein gene in retinoblastoma cell lines.

Cited by 92 publications

References 41 publications

Expression of two dead box gene (DDX1 amd DDX6) is independent of that of MYCN in human neuroblastoma cell lines

Expression of two dead box gene (DDX1 amd DDX6) is independent of that of MYCN in human neuroblastoma cell lines

Synergism between p68 RNA helicase and the transcriptional coactivators CBP and p300

An RNA Helicase, DDX1, Interacting with Poly(A) RNA and Heterogeneous Nuclear Ribonucleoprotein K

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