The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)



Gene Review

DDX21  -  DEAD (Asp-Glu-Ala-Asp) box helicase 21

Homo sapiens

Synonyms: DEAD box protein 21, GUA, GURDB, Gu-alpha, Nucleolar RNA helicase 2, ...
Welcome! If you are familiar with the subject of this article, you can contribute to this open access knowledge base by deleting incorrect information, restructuring or completely rewriting any text. Read more.

Disease relevance of DDX21

  • BACKGROUND/AIMS: Four different ribozymes (Rz) targeting the hepatitis C virus (HCV) 5'-non-coding region (NCR) at nucleotide (nt) positions GUA 165 (Rz1), GUC 270 (Rz2), GUA 330 (Rz3) and GCA 348 (Rz1293) were compared for in vitro cleavage using a 455 nt HCV RNA substrate [1].
  • Human nucleolar RNA helicase II/Gu protein (RH II/Gu) was expressed in a baculovirus system [2].

High impact information on DDX21

  • Changing the anticodon from GUA to the serine anticodon GGA resulted in a marked decrease in tyrosine charging activity, but this mutant did not show any serine charging activity [3].
  • Although previous observations have suggested that the G of the YAG/ interacts with the first nucleotide of the /GUA consensus sequence at the 5' end of the intron, additional interactions have not been identified [4].
  • Three hammerhead ribozymes with triplet specificities for cleavage 3' of CUC, GUC, and GUA have been evaluated for their sensitivity to the substitution of thymidine or 2'-deoxyuridine at central nucleotide position 16.1 in the substrate triplet [5].
  • An A-->T substitution in cDNA nucleotide 1197 (c.1197A/T) of the human phenylalanine hydroxylase (PAH) gene has been regarded as a silent mutation, because both the wild-type (GUA) and the mutant (GUU) alleles encode a valine residue at codon 399 (V399 V) [6].
  • The nucleotide sequences of tRNA(Asn) (GUU) and tRNA(Tyr) (GUA) genes from tomato mitochondria and their flanking regions have been determined [7].

Biological context of DDX21

  • Comparing the results with other methods of donor splice site prediction has demonstrated a more accurate prediction of consensus sequences AG/GU(A,G), G/GUnAG, /GU(A,G)AG, /GU(A,G)nGU, and G/GUA than is achieved by weight matrix and consensus (A,C)AG/GU(A,G)AGU with mismatches [8].
  • These genes, which are located in the same region of the genome between the 14-kb inverted repeats, are transcribed in the mitochondria and code for tRNA(Lys) (anticodon UUU) tRNA(Met) (CAU) and tRNA(Tyr) (GUA) [9].
  • Structure and expression of tomato mitochondrial genes coding for tRNA(Cys) (GCA), tRNA(Asn) (GUU) and tRNA(Tyr) (GUA): a native tRNA(Cys) gene is present in dicot plants but absent in monocot plants [7].
  • In particular, we propose a tertiary base-pairing interaction between the universal invariant GUA sequence (positions 76-78 and 75-77 in prokaryotic and eukaryotic 5S RNA, respectively) and the complementary conserved CPuU sequence (positions 38-40 and 36-38) in a parallel manner [10].

Anatomical context of DDX21

  • The best statistical relation of the number of sweat glands per unit area of skin (GUA) to surface area (SA) or age in children was the natural logarithm of GUA versus the reciprocal of surface area: LnGUA = (0.2205 X 1/SA) + 5.42 [11].

Associations of DDX21 with chemical compounds

  • Polyacrylamide gel electrophoresis and isoelectric focusing carried out on 4 M GUA extracts, demonstrated identical quantitative and qualitative distribution of 14C GlcN between the major SGP (140 and 110 K with pI 7.8 and 4.5 respectively) in the normal and the experimental groups [12].
  • The different 14C radiolabeled macromolecules were extracted sequentially by 0.4 M guanidinium chloride (0.4 M GUA), 4 M GUA and collagenase digestion [12].

Analytical, diagnostic and therapeutic context of DDX21

  • The possibility of transcript editing was investigated by RT-PCR, but psaA, psbA, psbB and atpB transcripts showed no evidence of editing, indicating that GUA can be used as an initiation codon in A. operculatum [13].


  1. Hammerhead ribozymes with cleavage site specificity for NUH and NCH display significant anti-hepatitis C viral effect in vitro and in recombinant HepG2 and CCL13 cells. Gonzalez-Carmona, M.A., Schüssler, S., Serwe, M., Alt, M., Ludwig, J., Sproat, B.S., Steigerwald, R., Hoffmann, P., Quasdorff, M., Schildgen, O., Caselmann, W.H. J. Hepatol. (2006) [Pubmed]
  2. Adriamycin inhibits human RH II/Gu RNA helicase activity by binding to its substrate. Zhu, K., Henning, D., Iwakuma, T., Valdez, B.C., Busch, H. Biochem. Biophys. Res. Commun. (1999) [Pubmed]
  3. Conversion of aminoacylation specificity from tRNA(Tyr) to tRNA(Ser) in vitro. Himeno, H., Hasegawa, T., Ueda, T., Watanabe, K., Shimizu, M. Nucleic Acids Res. (1990) [Pubmed]
  4. Genetic interactions between the 5' and 3' splice site consensus sequences and U6 snRNA during the second catalytic step of pre-mRNA splicing. Collins, C.A., Guthrie, C. RNA (2001) [Pubmed]
  5. Hammerhead ribozyme mechanism: a ribonucleotide 5' to the substrate cleavage site is not essential. Kore, A.R., Eckstein, F. Biochemistry (1999) [Pubmed]
  6. A silent mutation induces exon skipping in the phenylalanine hydroxylase gene in phenylketonuria. Chao, H.K., Hsiao, K.J., Su, T.S. Hum. Genet. (2001) [Pubmed]
  7. Structure and expression of tomato mitochondrial genes coding for tRNA(Cys) (GCA), tRNA(Asn) (GUU) and tRNA(Tyr) (GUA): a native tRNA(Cys) gene is present in dicot plants but absent in monocot plants. Izuchi, S., Terachi, T., Sakamoto, M., Mikami, T., Sugita, M. Curr. Genet. (1990) [Pubmed]
  8. Analysis of donor splice sites in different eukaryotic organisms. Rogozin, I.B., Milanesi, L. J. Mol. Evol. (1997) [Pubmed]
  9. Sequence analysis of the tRNA(Tyr) and tRNA(Lys) genes and evidence for the transcription of a chloroplast-like tRNA(Met) in maize mitochondria. Sangaré, A., Lonsdale, D., Weil, J.H., Grienenberger, J.M. Curr. Genet. (1989) [Pubmed]
  10. Universal structural features of prokaryotic and eukaryotic ribosomal 5S RNA derived from comparative analysis of their sequences. Böhm, S., Fabian, H., Welfle, H. Acta Biol. Med. Ger. (1982) [Pubmed]
  11. Microdissection study of the incidence of branched eccrine sweat glands and the number of eccrine glands per unit area of infants' and childrens' skin. Wells, T.R., Landing, B.H., Sandhu, M., Lipsey, A.I. Pediatric pathology / affiliated with the International Paediatric Pathology Association. (1986) [Pubmed]
  12. Biosynthesis of hyaluronic acid, heparan sulfate and structural glycoproteins in hamster lung explants during elastase induced emphysema. Lafuma, C., Moczar, M., Lange, F., Robert, L. Connect. Tissue Res. (1985) [Pubmed]
  13. Organisation and expression of the plastid genome of the dinoflagellate Amphidinium operculatum. Barbrook, A.C., Symington, H., Nisbet, R.E., Larkum, A., Howe, C.J. Mol. Genet. Genomics (2001) [Pubmed]
WikiGenes - Universities