One of the two Dicer-like proteins in the filamentous fungi Magnaporthe oryzae genome is responsible for hairpin RNA-triggered RNA silencing and related small interfering RNA accumulation.
Dicer is a ribonuclease III-like enzyme playing a key role in the RNA silencing pathway. Genome sequencing projects have demonstrated that eukaryotic genomes vary in the numbers of Dicer-like (DCL) proteins from one (human) to four (Arabidopsis). Two DCL genes, MDL-1 and -2 (Magnaporthe Dicer-like-1 and -2) have been identified in the genome of the filamentous fungus Magnaporthe oryzae. Here we show that the knockout of MDL-2 drastically impaired gene silencing of enhanced green fluorescence protein by hairpin RNA and reduced related small interfering RNA (siRNA) accumulation to nondetectable levels. In contrast, mutating the other DCL, MDL-1, exhibited a gene silencing frequency similar to wild type and accumulated siRNA normally. The silencing-deficient phenotype and loss of siRNA accumulation in the mdl-2 mutant was restored by genetic complementation with the wild-type MDL-2 allele. These results indicate that only MDL-2 is responsible for siRNA production, and no functional redundancy exists between MDL-1 and MDL-2 in the RNA silencing pathway in M. oryzae. Our findings contrast with a recent report in the filamentous fungus Neurospora crassa, where two DCL proteins are redundantly involved in the RNA silencing pathway, but are similar to the results obtained in a more distantly related organism, Drosophila melanogaster, where an individual DCL protein has a distinct role in the siRNA/micro-RNA pathways.[1]References
- One of the two Dicer-like proteins in the filamentous fungi Magnaporthe oryzae genome is responsible for hairpin RNA-triggered RNA silencing and related small interfering RNA accumulation. Kadotani, N., Nakayashiki, H., Tosa, Y., Mayama, S. J. Biol. Chem. (2004) [Pubmed]
Annotations and hyperlinks in this abstract are from individual authors of WikiGenes or automatically generated by the WikiGenes Data Mining Engine. The abstract is from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.About WikiGenesOpen Access LicencePrivacy PolicyTerms of Useapsburg
