1887

Abstract

The transcriptional activator XlnR from is a zinc binuclear cluster transcription factor that belongs to the GAL4 superfamily. Several putative structural domains in XlnR were predicted using database and protein sequence analysis. Thus far, only the functionality of the N-terminal DNA-binding domain has been determined experimentally. Deletion mutants of the gene were constructed to localize the functional regions of the protein. The results showed that a putative C-terminal coiled-coil region is involved in nuclear import of XlnR. After deletion of the C-terminus, including the coiled-coil region, XlnR was found in the cytoplasm, while deletion of the C-terminus downstream of the coiled-coil region resulted in nuclear import of XlnR. The latter mutant also showed increased xylanase activity, indicating the presence of a region with an inhibitory function in XlnR-controlled transcription. Previous findings had already shown that a mutation in the XlnR C-terminal region resulted in transcription of the structural genes under non-inducing conditions. A regulatory model of XlnR is presented in which the C-terminus responds to repressing signals, resulting in an inactive state of the protein.

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2004-05-01
2019-10-18
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References

  1. Blank, T. E., Woods, M. P., Lebo, C. M., Xin, P. & Hopper, J. E. ( 1997; ). Novel Gal3 proteins showing altered Gal80p binding cause constitutive transcription of GAL4p-activated genes in Saccharomyces cerevisiae. Mol Cell Biol 17, 2566–2575.
    [Google Scholar]
  2. Bogerd, H. P., Benson, R. E., Truant, R., Herolds, A., Phingbodhipakkiya, M. & Cullen, B. R. ( 1999; ). Definition of a consensus transportin-specific nucleocytoplasmic transport signal. J Biol Chem 274, 9771–9777.[CrossRef]
    [Google Scholar]
  3. Cazelle, B., Pokorska, A., Hull, E., Green, P. M., Stanway, G. & Scazzocchio, C. ( 1998; ). Sequence, exon-intron organization, transcription and mutational analysis of prnA, the gene encoding the transcriptional activator of the prn gene cluster in Aspergillus nidulans. Mol Microbiol 361, 355–370.
    [Google Scholar]
  4. Christophe, D., Christophe-Hobertus, C. & Pichon, B. ( 2000; ). Nuclear targetting of proteins: how many different signals? Cell Signal 12, 337–341.[CrossRef]
    [Google Scholar]
  5. Christophe-Hobertus, C., Duquesne, V., Pichon, B., Roger, P. P. & Christophe, D. ( 1999; ). Critical residues of the homeodomain involved in contacting DNA bases also specify the nuclear accumulation of thyroid transcription factor-1. Eur J Biochem 265, 491–497.[CrossRef]
    [Google Scholar]
  6. de Graaff, L. H., van den Broeck, H. C. & Visser, J. ( 1988; ). Isolation and transformation of the pyruvate kinase gene of Aspergillus nidulans. Curr Genet 13, 315–321.[CrossRef]
    [Google Scholar]
  7. Des Etages, S. A. G., Saxena, D., Huang, H. L., Falvey, D. A., Barber, D. & Brandriss, M. C. ( 2001; ). Conformational changes play a role in regulating the activity of the proline utilization pathway-specific regulator in Saccharomyces cerevisiae. Mol Microbiol 40, 890–899.[CrossRef]
    [Google Scholar]
  8. Fröhlich, T., Risau, W. & Flamme, I. ( 1998; ). Characterization of novel nuclear targeting and apoptosis-inducing domains in FAS associated factor 1. J Cell Sci 111, 2352–2363.
    [Google Scholar]
  9. Gielkens, M. M. C., Dekkers, E., Visser, J. & de Graaff, L. H. ( 1999; ). Two cellobiohydrolase-encoding genes from Aspergillus niger require d-xylose and the xylanolytic transcriptional activator XlnR for their expression. Appl Environ Microbiol 65, 4340–4345.
    [Google Scholar]
  10. Hasper, A. A., Visser, J. & de Graaff, L. H. ( 2000; ). The Aspergillus niger transcriptional activator XlnR, which is involved in the degradation of the polysaccharides xylan and cellulose, also regulates d-xylose reductase gene transcription. Mol Microbiol 36, 193–200.[CrossRef]
    [Google Scholar]
  11. Hasper, A. A., Dekker, E., van Mil, M., van de Vondervoort, P. J. I. & de Graaff, L. H. ( 2002; ). EglC, a new endoglucanase from Aspergillus niger with major activity towards xyloglucan. Appl Environ Microbiol 68, 1556–1560.[CrossRef]
    [Google Scholar]
  12. Keegan, L., Gill, G. & Ptashne, M. ( 1986; ). Separation of DNA binding from the transcription activation function of a eukaryotic regulatory protein. Science 231, 699–704.[CrossRef]
    [Google Scholar]
  13. Komeili, A. & O'Shea, E. K. ( 1999; ). Roles of phosphorylation sites in regulating activity of the transcription factor Pho4. Science 284, 977–980.[CrossRef]
    [Google Scholar]
  14. Kusters-van Someren, M. A., Harmsen, J. A. M., Kester, H. C. M. & Visser, J. ( 1991; ). Structure of the Aspergillus niger pelA gene and its expression in Aspergillus niger and Aspergillus nidulans. Curr Genet 20, 293–299.[CrossRef]
    [Google Scholar]
  15. Lupas, A., van Dyke, M. & Stock, J. ( 1991; ). Predicting coiled coils from protein sequences. Science 252, 1162–1164.[CrossRef]
    [Google Scholar]
  16. Ma, J. & Ptashne, M. ( 1987; ). Deletion analysis of GAL4 defines two transcriptional activating segments. Cell 48, 847–853.[CrossRef]
    [Google Scholar]
  17. Nigg, E. A. ( 1997; ). Nucleocytoplasmic transport: signals, mechanisms and regulation. Nature 386, 779–787.[CrossRef]
    [Google Scholar]
  18. Palmeri, D. & Malim, M. H. ( 1999; ). Importin beta can mediate the nuclear import of an arginine-rich nuclear localisation signal in the absence of importin alpha. Mol Cell Biol 19, 1218–1225.
    [Google Scholar]
  19. Patschinsky, T., Hunter, T., Esch, F. S., Cooper, J. A. & Sefton, B. M. ( 1982; ). Analysis of the sequence of amino acids surrounding sites of tyrosine phosphorylation. Proc Natl Acad Sci USA 79, 973–977.[CrossRef]
    [Google Scholar]
  20. Peng, G. & Hopper, J. E. ( 2002; ). Gene activation by interaction of an inhibitor with a cytoplasmatic signaling protein. Proc Natl Acad Sci U S A 99, 8548–8553.[CrossRef]
    [Google Scholar]
  21. Pokorska, A., Drevet, C. & Scazzocchio, C. ( 2000; ). The analysis of the transcriptional activator PrnA reveals a tripartite nuclear localisation sequence. J Mol Biol 298, 585–596.[CrossRef]
    [Google Scholar]
  22. Pollard, V. W., Michael, W. M., Nakielny, S., Siomi, M. C., Wang, F. & Dreyfuss, G. ( 1996; ). A novel receptor-mediated nuclear protein import pathway. Cell 86, 985–994.[CrossRef]
    [Google Scholar]
  23. Pontecorvo, G., Roper, J. A., Hemmons, L. J., MacDonald, K. D. & Bufton, A. W. J. ( 1953; ). The genetics of Aspergillus nidulans. Adv Genet 5, 141–238.
    [Google Scholar]
  24. Sambrook, J., Fritsch, E. F. & Maniatis, T. ( 1989; ). Molecular Cloning: a Laboratory Manual, 2nd edn. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory.
  25. Strauss, J., Muro-Pastor, M. I. & Scazzocchio, C. ( 1998; ). The regulator of nitrate assimilation in ascomycetes is a dimer which binds a non-repeated, asymmetrical sequence. Mol Cell Biol 18, 1339–1348.
    [Google Scholar]
  26. Suárez, T., de Queiroz, M. V., Oestreicher, N. & Scazzocchio, C. ( 1995; ). The sequence and binding specificity of UaY, the specific regulator of the purine utilization pathway in Aspergillus nidulans, suggest an evolutionary relationship with the PPR1 protein of Saccharomyces cerevisiae. EMBO J 14, 1453–1467.
    [Google Scholar]
  27. Truant, R. & Cullen, B. R. ( 1999; ). The arginine-rich domains present in human immunodeficiency virus type 1 Tat and Rev function as direct importin β-dependent nuclear localization signals. Mol Cell Biol 19, 1210–1217.
    [Google Scholar]
  28. Van Peij, N. N. M. E., van Visser, J. & de Graaff, L. H. ( 1998a; ). Isolation and analysis of xlnR, encoding a transcriptional activator co-ordinating xylanolytic expression in Aspergillus niger. Mol Microbiol 27, 131–142.[CrossRef]
    [Google Scholar]
  29. Van Peij, N. N. M. E., Gielkens, M. M. C., de Vries, R. P., Visser, J. & de Graaff, L. H. ( 1998b; ). The transcriptional activator XlnR regulates both xylanolytic and endoglucanase gene expression in Aspergillus niger. Appl Environ Microbiol 64, 3615–3619.
    [Google Scholar]
  30. Wang, D., Hu, Y., Zheng, F., Zhou, K. & Kohlhaw, G. B. ( 1997; ). Evidence that intramolecular interactions are involved in masking the activation domain of transcriptional activator Leu3p. J Biol Chem 272, 19383–19392.[CrossRef]
    [Google Scholar]
  31. Wang, D., Zheng, F., Holmberg, S. & Kohlhaw, G. B. ( 1999; ). Yeast transcriptional regulator Leu3p. Self-masking, specificity of masking, and evidence for regulation by the intracellular level of Leu3p. J Biol Chem 274, 19017–19024.[CrossRef]
    [Google Scholar]
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