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Ribosomal DNA insertion elements R1Bm and R2Bm can transpose in a sequence specific manner to locations outside the 28S genes
- Source :
- Nucleic Acids Research; November 1988, Vol. 16 Issue: 22 p10561-10561, 1p
- Publication Year :
- 1988
-
Abstract
- A fraction of the ribosomal 28S genes in some insects are interrupted at specific sites by insertion elements R1 and R2 (also called Type I and II). These elements contain long open-reading frames with homology to reverse transcriptase. We have identified in the silkmoth, Bombyx mori</it>, copies of these elements which have inserted into sites outside the ribosomal DNA (rDNA) units. The 3′ ends of all “non-rDNA” elements are identical to the elements within the 28S genes; however their 5′ ends are often truncated. Each non-rDNA copy has inserted into sequences that exhibit similarity to their target sites in the 28S gene. We also demonstrate by genomic blot analysis of different strains of B. mori</it> that insertions of R1 and R2 outside the rDNA units have been infrequent, while considerable turnover of elements has occurred within the rDNA locus. One race of B. mori</it> has lost all copies of R1 from its rDNA units, while retaining normal levels of R2. The level of both R1 and R2 have significantly increased in a tissue culture line. These findings add considerable support to the model that R1 and R2 are retrotransposable elements that utilize sequence specific endonucleases in their integration into the genome.
Details
- Language :
- English
- ISSN :
- 03051048 and 13624962
- Volume :
- 16
- Issue :
- 22
- Database :
- Supplemental Index
- Journal :
- Nucleic Acids Research
- Publication Type :
- Periodical
- Accession number :
- ejs35935961
- Full Text :
- https://doi.org/10.1093/nar/16.22.10561