Quelling: transient inactivation of gene expression in Neurospora crassa by transformation with homologous sequences

@article{Romano1992QuellingTI,
  title={Quelling: transient inactivation of gene expression in Neurospora crassa by transformation with homologous sequences},
  author={Nicoletta Romano and Giuseppe Macino},
  journal={Molecular Microbiology},
  year={1992},
  volume={6}
}
Up to 36% of Neurospora crassa transformants showing an albino phenotype were recovered by transforming a wild‐type strain with different portions of the carotenogenic albino‐3 (al‐3) and albino‐1 (al‐1) genes. The presence of the exogenous sequences (which were randomly integrated in ectopic locations) provoked a severe impairment in the expression of the endogenous al‐1 or al‐3 genes. This phenomenon, which we have termed‘quelling’, was found to be spontaneously and progressively reversible… Expand
Suppression of gene expression by homologous transgenes
TLDR
All of the albino transformants have an unstable phenotype and revert progressively to wild type or intermediate phenotypes over a prolonged culturing time, and there is no strict correlation between the copy number of the ectopic sequences and the intensity of quelling. Expand
Quelling: transgene-induced gene silencing in Neurospora crassa
TLDR
Gene inactivation by quelling is the result of the suppression of gene expression, through a reduction of the steady-state mRNA level of the duplicated gene, and is reversible and the function of the inactivated gene may be restored after prolonged culturing time. Expand
9 Quelling in Neurospora crassa
TLDR
Evidence that quelling is a general mechanism, not limited to specific genes in Neurospora, was provided by the fact that the qa-2 gene encoding the quinic acid dehydrogenase used as a genetic marker for transformation in experiments was also silenced. Expand
Efficient gene silencing by expression of double stranded RNA in Neurospora crassa.
TLDR
It is shown that the use of constructs that express hairpin double stranded RNA (dsRNA) permits efficient gene silencing by-passing limiting events in the quelling triggering process occurring upstream of dsRNA production, which makes this method suitable for producing hypomorphic mutants in N. crassa. Expand
Methylation of the foreign transposon Restless in vegetative mycelia of Neurospora crassa
TLDR
Methylation of foreign and/or repeated sequences in the filamentous fungus Neurospora crassa is believed to be directed against invading transposable elements, and vectors constructed which carried the transposon Restless, an active class-II element isolated from the fungus Tolypocladium inflatum were investigated. Expand
Homology-Dependent Silencing of the SC 3 Gene in Schixophyllum commune The 0
After introduction of extra copies of the SC3 hydrophobin gene into a wild-type strain of Schizophyllum commune, gene silencing was observed acting on both endogenous and introduced SC3 genes inExpand
Isolation of quelling-defective (qde) mutants impaired in posttranscriptional transgene-induced gene silencing in Neurospora crassa.
  • C. Cogoni, G. Macino
  • Biology, Medicine
  • Proceedings of the National Academy of Sciences of the United States of America
  • 1997
TLDR
It is shown that when qde genes are mutated in a transgenic-induced silenced strain containing many copies of the transgene, the expression of the endogenous gene is maintained despite the presence of transGene sense RNA, the molecule proposed to trigger quelling. Expand
Gene inactivation in Arabidopsis thaliana is not accompanied by an accumulation of repeat-induced point mutations
TLDR
Comparison of data from transgenic lines of Arabidopsis thaliana containing the hygromycin phosphotransferase gene with those from Neurospora suggest that sequence divergence within plant repetitive DNA is either much slower than in neurospora or is generated by a different mechanism. Expand
Quelling: post-transcriptional gene silencing guided by small RNAs in Neurospora crassa.
TLDR
The filamentous fungus Neurospora crassa is a model organism for the study of gene silencing and it has been recently shown that quelling is needed for the taming of transposons but, unlike other model organisms, does not seem to play any role in heterochromatin assembly and maintenance. Expand
Gene silencing in Neurospora crassa requires a protein homologous to RNA-dependent RNA polymerase
TLDR
The cloning of qde-1, the first cellular component of the gene-silencing mechanism to be isolated, defines a new gene family conserved among different species including plants, animals and fungi, which is similar to an RNA-dependent RNA polymerase found in the tomato. Expand
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