Abstract
The repeat-induced point mutation mechanism (RIP) is the most intriguing among the known mechanisms of homology-dependent gene inactivation (silencing) because of its ability to produce irreversible mutations in repetitive DNA sequences. Discovered for the first time in Neurospora crassa, RIP is characterized by C:G to T:A transitions in duplicated sequences. The mechanisms and range of occurrence of RIP are still poorly understood. Mobile elements, including retrotransposons, are a common target for the processes that lead to homology-dependent silencing because of their ability to propagate themselves. Comparative analysis of LTR retrotransposons was performed throughout the genomes of two ascomycetes, Aspergillus fumigatus and A. nidulans. “De-RIP” retroelements were reconstructed on the basis of several copies. CpG, CpA, and TpG sites, which are potential targets for mutagenesis, were found at a much lower frequency in mobile elements than in structural genes. The dinucleotide targets of the two species are affected by RIP at different frequencies: mutagenesis occurs at both CpG and CpA sites in A. fumigatus and is confined to CpG dinucleotides in A. nidulans. This work provides a theoretical background for planning the experimental investigation of RIP inactivation in aspergilli.
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Original Russian Text © O.S. Novikova, V. Fet, A.G. Blinov, 2007, published in Molekulyarnaya Biologiya, 2007, Vol. 41, No. 6, pp. 973–981.
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Novikova, O.S., Fet, V. & Blinov, A.G. Homology-dependent inactivation of LTR retrotransposons in Aspergillus fumigatus and A. nidulans genomes. Mol Biol 41, 886–893 (2007). https://doi.org/10.1134/S0026893307060039
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DOI: https://doi.org/10.1134/S0026893307060039