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

truA  -  tRNA pseudouridine(38-40) synthase

Escherichia coli str. K-12 substr. MG1655

Synonyms: ECK2312, JW2315, asuC, hisT, leuK
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 truA


High impact information on truA

  • Evidence is presented that hisT mutants (which lack pseudouridine in the anticodon arm of histidine tRNA) may cause derepression of the his operon by slowing protein synthesis in the leader peptide gene [5].
  • In the absence of other proteins, purified tRNA pseudouridine synthase I forms psi at all three modification sites known to be affected in hisT mutants [6].
  • Two other genes, denoted dedC and dedD, have been localized between the hisT and purF operons [1].
  • The distal hisT gene encodes the tRNA modification enzyme, pseudouridine synthase I, which was shown to have a polypeptide molecular mass of 30,399 daltons [7].
  • The DNA sequence was consistent with the phenotypes and hisT expression of mutant operons [7].

Chemical compound and disease context of truA


Biological context of truA

  • Indeed, a truA mutant is defective in type III gene expression while its twitching motility is unaffected, and a truA clone is able to complement the type III secretion defect [2].
  • Pseudouridination of tRNAs is important for tRNA structure, thereby improving the fidelity of protein synthesis and helping to maintain the proper reading frame; thus the results imply that truA controls tRNAs that are critical for the translation of type III genes or their regulators [2].
  • The DNA sequence of a 2,3-kilobase segment of the E. coli hisT operon was determined [7].
  • There is very little protein sequence homology between the truB gene product and the hisT (truA) product, which forms psi in the anticodon arm of tRNAs [11].
  • Subclones containing restriction fragments from plasmid psi 300 inserted downstream from the lac promoter established that the hisT gene is oriented from the HindIII site toward the ClaI site [4].

Associations of truA with chemical compounds

  • Expression in both of these mutants was unaltered by the presence of the hisT allele or by the addition of threonine and isoleucine to the growth medium [12].
  • In a hisT strain (which has altered leucyl-tRNA), transhydrogeanse was at a repressed level without the addition of leucine, suggesting that leucyl-tRNA may be involved in the regulation [13].
  • Furthermore, in tRNA3Leu and tRNA4Leu from a leuK strain, uridine residues at positions 39 and 40, respectively, are unmodified [3].
  • A new locus (leuK) affecting the regulation of branched-chain amino acid, histidine, and tryptophan biosynthetic enzymes [10].
  • However, the level of derepression of DAP-decarboxylase, the last enzyme of the lysine pathway, is very low in the hisT mutant; this indicates that tRNAlys is a secondary effector involved in the regulation of the synthesis of this enzyme [14].

Physical interactions of truA


Other interactions of truA

  • We show that the minimum size of the operon is approximately 3,500 base pairs and that it contains at least four genes, which are arranged in the order usg-2 (pdxB), usg-1, hisT, and dsg-1 and encode polypeptides with apparent molecular masses of 42,000, 45,000, 31,000, and 17,000 daltons, respectively [9].
  • An example using this technique in which the product of the usg gene in the hisT operon of E. coli has been purified and biochemically characterized is described [16].

Analytical, diagnostic and therapeutic context of truA

  • Sequence analysis showed that the insertion disrupted hisT, the gene encoding pseudouridine synthase I, a tRNA-modifying enzyme. hisT::Tn5 mutant cells were also shown to be defective for the production of other antibiotic peptides, such as microcin C7, microcin H47, and colicin V [17].
  • Transductional analysis showed that the altered regulation is due to the presence of a mutation in hisT, the gene for the tRNA modification enzyme pseudouridine synthetase I. A complementation test showed that the regulatory defect conferred by the hisT mutation was recessive [18].


  1. The hisT-purF region of the Escherichia coli K-12 chromosome. Identification of additional genes of the hisT and purF operons. Nonet, M.L., Marvel, C.C., Tolan, D.R. J. Biol. Chem. (1987) [Pubmed]
  2. The truA gene of Pseudomonas aeruginosa is required for the expression of type III secretory genes. Ahn, K.S., Ha, U., Jia, J., Wu, D., Jin, S. Microbiology (Reading, Engl.) (2004) [Pubmed]
  3. Escherichia coli B/r leuK mutant lacking pseudouridine synthase I activity. Searles, L.L., Jones, J.W., Fournier, M.J., Grambow, N., Tyler, B., Calvo, J.M. J. Bacteriol. (1986) [Pubmed]
  4. hisT is part of a multigene operon in Escherichia coli K-12. Marvel, C.C., Arps, P.J., Rubin, B.C., Kammen, H.O., Penhoet, E.E., Winkler, M.E. J. Bacteriol. (1985) [Pubmed]
  5. Model for regulation of the histidine operon of Salmonella. Johnston, H.M., Barnes, W.M., Chumley, F.G., Bossi, L., Roth, J.R. Proc. Natl. Acad. Sci. U.S.A. (1980) [Pubmed]
  6. Purification, structure, and properties of Escherichia coli tRNA pseudouridine synthase I. Kammen, H.O., Marvel, C.C., Hardy, L., Penhoet, E.E. J. Biol. Chem. (1988) [Pubmed]
  7. Structural features of the hisT operon of Escherichia coli K-12. Arps, P.J., Marvel, C.C., Rubin, B.C., Tolan, D.A., Penhoet, E.E., Winkler, M.E. Nucleic Acids Res. (1985) [Pubmed]
  8. 1H-15N NMR studies of Escherichia coli tRNA(Phe) from hisT mutants: a structural role for pseudouridine. Davis, D.R., Poulter, C.D. Biochemistry (1991) [Pubmed]
  9. Structural analysis of the Escherichia coli K-12 hisT operon by using a kanamycin resistance cassette. Arps, P.J., Winkler, M.E. J. Bacteriol. (1987) [Pubmed]
  10. A new locus (leuK) affecting the regulation of branched-chain amino acid, histidine, and tryptophan biosynthetic enzymes. Brown, C.S., West, R., Hilderman, R.H., Bayliss, F.T., Klines, E.L. J. Bacteriol. (1978) [Pubmed]
  11. Purification, cloning, and properties of the tRNA psi 55 synthase from Escherichia coli. Nurse, K., Wrzesinski, J., Bakin, A., Lane, B.G., Ofengand, J. RNA (1995) [Pubmed]
  12. Specificity of the attenuation response of the threonine operon of Escherichia coli is determined by the threonine and isoleucine codons in the leader transcript. Lynn, S.P., Burton, W.S., Donohue, T.J., Gould, R.M., Gumport, R.I., Gardner, J.F. J. Mol. Biol. (1987) [Pubmed]
  13. Repression of Escherichia coli pyridine nucleotide transhydrogenase by leucine. Gerolimatos, B., Hanson, R.L. J. Bacteriol. (1978) [Pubmed]
  14. Effect of mutations affecting lysyl-tRNAlys on the regulation of lysine biosynthesis in Escherichia coli. Boy, E., Borne, F., Patte, J.C. Mol. Gen. Genet. (1978) [Pubmed]
  15. Divergent transcription of pdxB and homology between the pdxB and serA gene products in Escherichia coli K-12. Schoenlein, P.V., Roa, B.B., Winkler, M.E. J. Bacteriol. (1989) [Pubmed]
  16. Purification of plasmid-expressed proteins which lack functional assay systems. Marvel, C.C., Kammen, H.O. Anal. Biochem. (1989) [Pubmed]
  17. A hisT::Tn5 mutation affects production of microcins B17, C7, and H47 and colicin V. Rodríguez-Sáinz, M.C., Hernández-Chico, C., Moreno, F. J. Bacteriol. (1991) [Pubmed]
  18. Altered growth-rate-dependent regulation of 6-phosphogluconate dehydrogenase level in hisT mutants of Salmonella typhimurium and Escherichia coli. Jones, W.R., Barcak, G.J., Wolf, R.E. J. Bacteriol. (1990) [Pubmed]
WikiGenes - Universities