title: The P-element-induced silencing effect of KP transposons is dose dependent in Drosophila melanogaster.
abstract: Transposable elements are found in the genomes of all eukaryotes and play a critical role in altering gene expression and genome organization. In Drosophila melanogaster, transposable P elements are responsible for the phenomenon of hybrid dysgenesis. KP elements, a deletion-derivative of the complete P element, can suppress this mutagenic effect. KP elements can also silence the expression of certain other P-element-mediated transgenes in a process called P-element-dependent silencing (PDS), which is thought to involve the recruitment of heterochromatin proteins. To explore the mechanism of this silencing, we have mobilized KP elements to create a series of strains that contain single, well-defined KP insertions that show PDS. To understand the quantitative role of KP elements in PDS, these single inserts were combined in a series of crosses to obtain genotypes with zero, one, or two KP elements, from which we could examine the effect of KP gene dose. The extent of PDS in these genotypes was shown to be dose dependent in a logarithmic rather than linear fashion. A logarithmic dose dependency is consistent with the KP products interacting with heterochromatic proteins in a concentration-dependent manner such that two molecules are needed to induce gene silencing.
authors: Department of Biological Sciences, University of Alberta, Edmonton, Canada.
authors: Alireza
authors: A
authors: Sameny
authors: John
authors: J
authors: Locke
mesh_terms: D000818:Animals; D001483:Base Sequence; D056915:DNA Copy Number Variations / Q000235:genetics*; D004251:DNA Transposable Elements / Q000235:genetics*; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics*; D005127:Eye Color / Q000235:genetics; D018628:Gene Dosage; D005786:Gene Expression Regulation; D020868:Gene Silencing; D005838:Genotype; D006570:Heterochromatin / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D010857:Pigment Epithelium of Eye / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D037941:Silencer Elements, Transcriptional / Q000235:genetics
chemical_list: D004251:DNA Transposable Elements; D029721:Drosophila Proteins; D006570:Heterochromatin; D009687:Nuclear Proteins; C092281:PSI protein, Drosophila; D016601:RNA-Binding Proteins