Integration of multiple repeats of geminiviral DNA into the nuclear genome of tobacco during evolution.
AUTOR(ES)
Bejarano, E R
RESUMO
Integration of viral DNA into the host nuclear genome, although not unusual in bacterial and animal systems, has surprisingly not been reported for plants. We have discovered geminvirus-related DNA (GRD) sequences, in the form of distinct sets of multiple direct repeats comprising three related repeat classes, situated in a unique locus in the Nicotiana tabacum (tobacco) nuclear genome. The organization of these sequences is similar or identical in eight different tobacco cultivars we have examined. DNA sequence analysis reveals that each repeat has sequences most resembling those of the New World geminiviral DNA replication origin plus the adjacent AL1 gene, encoding the viral replication protein. We believe these GRD sequences originated quite recently in Nicotiana evolution through integration of geminiviral DNA by some combination of the processes of illegitimate recombination, amplification, deletions, and rearrangements. These events must have occurred in plant tissue that was subsequently able to contribute to meristematic tissue yielding gametes. GRD may have been retained in tobacco by selection or by random fixation in a small evolving population. Although we cannot detect transcription of these sequences, this does not exclude the possibility that they may originally have been expressed.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=40128Documentos Relacionados
- Targeted Integration of T-DNA into the Tobacco Genome at Double-Stranded Breaks: New Insights on the Mechanism of T-DNA Integration
- Origin of noncoding DNA sequences: molecular fossils of genome evolution.
- Adeno-associated virus Rep78 protein and terminal repeats enhance integration of DNA sequences into the cellular genome.
- Integration of heterologous plasmid DNA into multiple sites on the genome of Campylobacter coli following natural transformation.
- Mitochondrial genome: defects, disease, and evolution.