Dataset Information

Insertion site preferences of the P transposable element in Drosophila melanogaster.

ABSTRACT: We determined the genomic sequence at the site of insertion in 2,266 unselected P element insertion events. Estimating physical properties of the genomic DNA at these insertion sites-such as base composition, bendability, A-philicity, protein-induced deformability, and B-DNA twist-revealed that they differ significantly from average chromosomal DNA. By examining potential hydrogen bonding sites in the major groove, we identified a 14-bp palindromic pattern centered on the 8-bp target site duplication that is generated by P element insertion. Our results suggest that the P-element transposition mechanism has a two-fold dyad symmetry and recognizes a structural feature at insertion sites, rather than a specific sequence motif.

SUBMITTER: Liao GC

PROVIDER: S-EPMC16242 | biostudies-literature | 2000 Mar

REPOSITORIES: biostudies-literature

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Publications

Insertion site preferences of the P transposable element in Drosophila melanogaster.

Liao G C GC Rehm E J EJ Rubin G M GM

Proceedings of the National Academy of Sciences of the United States of America 20000301 7

We determined the genomic sequence at the site of insertion in 2,266 unselected P element insertion events. Estimating physical properties of the genomic DNA at these insertion sites-such as base composition, bendability, A-philicity, protein-induced deformability, and B-DNA twist-revealed that they differ significantly from average chromosomal DNA. By examining potential hydrogen bonding sites in the major groove, we identified a 14-bp palindromic pattern centered on the 8-bp target site duplic ...[more]

PMID: 10716700

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Project description:Transposable elements (TE) are selfish genetic elements that can cause harmful mutations. In Drosophila, it has been estimated that half of all spontaneous visible marker phenotypes are mutations caused by TE insertions. Several factors likely limit the accumulation of exponentially amplifying TEs within genomes. First, synergistic interactions between TEs that amplify their harm with increasing copy number are proposed to limit TE copy number. However, the nature of this synergy is poorly understood. Second, because of the harm posed by TEs, eukaryotes have evolved systems of small RNA-based genome defense to limit transposition. However, as in all immune systems, there is a cost of autoimmunity and small RNA-based systems that silence TEs can inadvertently silence genes flanking TE insertions. In a screen for essential meiotic genes in Drosophila melanogaster, a truncated Doc retrotransposon within a neighboring gene was found to trigger the germline silencing of ald, the Drosophila Mps1 homolog, a gene essential for proper chromosome segregation in meiosis. A subsequent screen for suppressors of this silencing identified a new insertion of a Hobo DNA transposon in the same neighboring gene. Here we describe how the original Doc insertion triggers flanking piRNA biogenesis and local gene silencing. We show that this local gene silencing occurs in cis and is dependent on deadlock, a component of the Rhino-Deadlock-Cutoff (RDC) complex, to trigger dual-strand piRNA biogenesis at TE insertions. We further show how the additional Hobo insertion leads to de-silencing by reducing flanking piRNA biogenesis triggered by the original Doc insertion. These results support a model of TE-mediated gene silencing by piRNA biogenesis in cis that depends on local determinants of transcription. This may explain complex patterns of off-target gene silencing triggered by TEs within populations and in the laboratory. It also provides a mechanism of sign epistasis among TE insertions, illuminates the complex nature of their interactions and supports a model in which off-target gene silencing shapes the evolution of the RDC complex.

Dataset Information

Insertion site preferences of the P transposable element in Drosophila melanogaster.

Publications

Insertion site preferences of the P transposable element in Drosophila melanogaster.

Similar Datasets

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