Skip to main content
NCBI home page
Genetics logoLink to Genetics
. 1996 Feb;142(2):417–423. doi: 10.1093/genetics/142.2.417

Activator-Independent Gene Expression in Neurospora Crassa

W K Versaw 1, R L Metzenberg 1
PMCID: PMC1206976  PMID: 8852841

Abstract

A transgenic position effect that causes activator-independent gene expression has been described previously for three Neurospora crassa phosphate-repressible genes. We report analogous findings for two additional positively regulated genes, qa-2(+) and ars-1(+), indicating that such position effects are not limited to genes involved in phosphorus metabolism. In addition, we have characterized a number of mutants that display activator-independent gene expression. Each of these mutants contains a chromosomal rearrangement with one breakpoint located in the 5'-upstream region of the affected gene. This suggests that the rearrangements are associated with activator-independent gene expression and that these cis-acting mutations may represent a position effect similar to that responsible for rendering some transgenes independent of their transcriptional activators. We suggest that positively regulated genes in N. crassa are normally held in a transcriptionally repressed state by a cis-acting mechanism until specifically activated. Disruption of this cis-acting mechanism, either by random integration of a gene by transformation or by chromosomal rearrangement, renders these genes independent or partly independent of the transcriptional activator on which they normally depend.

Full Text

The Full Text of this article is available as a PDF (716.1 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Akins R. A., Lambowitz A. M. General method for cloning Neurospora crassa nuclear genes by complementation of mutants. Mol Cell Biol. 1985 Sep;5(9):2272–2278. doi: 10.1128/mcb.5.9.2272. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Alix J. H. Molecular aspects of the in vivo and in vitro effects of ethionine, an analog of methionine. Microbiol Rev. 1982 Sep;46(3):281–295. doi: 10.1128/mr.46.3.281-295.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Case M. E., Giles N. H. Genetic evidence on the organization and action of the qa-1 gene product: a protein regulating the induction of three enzymes in quinate catabolism in Neurospora crassa. Proc Natl Acad Sci U S A. 1975 Feb;72(2):553–557. doi: 10.1073/pnas.72.2.553. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Eissenberg J. C., Elgin S. C. Boundary functions in the control of gene expression. Trends Genet. 1991 Oct;7(10):335–340. doi: 10.1016/0168-9525(91)90424-o. [DOI] [PubMed] [Google Scholar]
  5. Geever R. F., Case M. E., Tyler B. M., Buxton F., Giles N. H. Point mutations and DNA rearrangements 5' to the inducible qa-2 gene of Neurospora allow activator protein-independent transcription. Proc Natl Acad Sci U S A. 1983 Dec;80(23):7298–7302. doi: 10.1073/pnas.80.23.7298. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Jeang K. T., Khoury G. The mechanistic role of enhancer elements in eukaryotic transcription. Bioessays. 1988 Apr;8(4):104–107. doi: 10.1002/bies.950080404. [DOI] [PubMed] [Google Scholar]
  7. Kalos M., Fournier R. E. Position-independent transgene expression mediated by boundary elements from the apolipoprotein B chromatin domain. Mol Cell Biol. 1995 Jan;15(1):198–207. doi: 10.1128/mcb.15.1.198. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Kang S., Metzenberg R. L. Molecular analysis of nuc-1+, a gene controlling phosphorus acquisition in Neurospora crassa. Mol Cell Biol. 1990 Nov;10(11):5839–5848. doi: 10.1128/mcb.10.11.5839. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Klehr D., Maass K., Bode J. Scaffold-attached regions from the human interferon beta domain can be used to enhance the stable expression of genes under the control of various promoters. Biochemistry. 1991 Feb 5;30(5):1264–1270. doi: 10.1021/bi00219a015. [DOI] [PubMed] [Google Scholar]
  10. Kornberg R. D., Lorch Y. Interplay between chromatin structure and transcription. Curr Opin Cell Biol. 1995 Jun;7(3):371–375. doi: 10.1016/0955-0674(95)80092-1. [DOI] [PubMed] [Google Scholar]
  11. Krug M. S., Berger S. L. First-strand cDNA synthesis primed with oligo(dT). Methods Enzymol. 1987;152:316–325. doi: 10.1016/0076-6879(87)52036-5. [DOI] [PubMed] [Google Scholar]
  12. LESTER H. E., GROSS S. R. Efficient method for selection of auxotrophic mutants of Neurospora. Science. 1959 Feb 27;129(3348):572–572. doi: 10.1126/science.129.3348.572. [DOI] [PubMed] [Google Scholar]
  13. Matile P. Inositol deficiency resulting in death: an explanation of its occurrence in Neurospora crassa. Science. 1966 Jan 7;151(3706):86–88. doi: 10.1126/science.151.3706.86. [DOI] [PubMed] [Google Scholar]
  14. Metzenberg R. L., Chia W. Genetic control of phosphorus assimilation in Neurospora crassa: dose-dependent dominance and recessiveness in constitutive mutants. Genetics. 1979 Nov;93(3):625–643. doi: 10.1093/genetics/93.3.625. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Metzenberg R. L. Implications of some genetic control mechanisms in Neurospora. Microbiol Rev. 1979 Sep;43(3):361–383. doi: 10.1128/mr.43.3.361-383.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Nelson M. A., Metzenberg R. L. Sexual development genes of Neurospora crassa. Genetics. 1992 Sep;132(1):149–162. doi: 10.1093/genetics/132.1.149. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Paietta J. V. Molecular cloning and regulatory analysis of the arylsulfatase structural gene of Neurospora crassa. Mol Cell Biol. 1989 Sep;9(9):3630–3637. doi: 10.1128/mcb.9.9.3630. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Paietta J. V. Production of the CYS3 regulator, a bZIP DNA-binding protein, is sufficient to induce sulfur gene expression in Neurospora crassa. Mol Cell Biol. 1992 Apr;12(4):1568–1577. doi: 10.1128/mcb.12.4.1568. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Peleg Y., Metzenberg R. L. Analysis of the DNA-binding and dimerization activities of Neurospora crassa transcription factor NUC-1. Mol Cell Biol. 1994 Dec;14(12):7816–7826. doi: 10.1128/mcb.14.12.7816. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Perkins D. D. The manifestation of chromosome rearrangements in unordered asci of Neurospora. Genetics. 1974 Jul;77(3):459–489. doi: 10.1093/genetics/77.3.459. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Stief A., Winter D. M., Strätling W. H., Sippel A. E. A nuclear DNA attachment element mediates elevated and position-independent gene activity. Nature. 1989 Sep 28;341(6240):343–345. doi: 10.1038/341343a0. [DOI] [PubMed] [Google Scholar]
  22. Versaw W. K. A phosphate-repressible, high-affinity phosphate permease is encoded by the pho-5+ gene of Neurospora crassa. Gene. 1995 Feb 3;153(1):135–139. doi: 10.1016/0378-1119(94)00814-9. [DOI] [PubMed] [Google Scholar]
  23. Wallrath L. L., Lu Q., Granok H., Elgin S. C. Architectural variations of inducible eukaryotic promoters: preset and remodeling chromatin structures. Bioessays. 1994 Mar;16(3):165–170. doi: 10.1002/bies.950160306. [DOI] [PubMed] [Google Scholar]
  24. Wilson C., Bellen H. J., Gehring W. J. Position effects on eukaryotic gene expression. Annu Rev Cell Biol. 1990;6:679–714. doi: 10.1146/annurev.cb.06.110190.003335. [DOI] [PubMed] [Google Scholar]
  25. Wolffe A. P. The transcription of chromatin templates. Curr Opin Genet Dev. 1994 Apr;4(2):245–254. doi: 10.1016/s0959-437x(05)80051-6. [DOI] [PubMed] [Google Scholar]
  26. Workman J. L., Buchman A. R. Multiple functions of nucleosomes and regulatory factors in transcription. Trends Biochem Sci. 1993 Mar;18(3):90–95. doi: 10.1016/0968-0004(93)90160-o. [DOI] [PubMed] [Google Scholar]

Articles from Genetics are provided here courtesy of Oxford University Press

RESOURCES