Telomeric transgenes and trans-silencing in Drosophila.
Autonomous P elements, inserted in heterochromatic telomeric associated sequences (TAS) at the X chromosome telomere (site 1A) have strong P element regulatory properties that include repression of P-induced hybrid-dysgenesis and of P-lacZ expression in the germline. P-lacZ insertions or defective P elements at 1A in TAS can also repress in trans a euchromatic P-lacZ in the germline. This property has been called a trans-silencing effect (TSE). It requires some sequence-homology between the telomeric insertion and the euchromatic transgene. When repression is partial, variegating lacZ expression is observed, suggesting a chromatin-based component. TSE is observed only when the silencer transgenes are maternally inherited and occurs only in the female germline. We have evidence that this silencing also works in the presence of homologous non-P element sequences suggesting that homology-dependent silencing could be a general phenomenon in the female germline; such a system might have been subsequently adopted by the P element family, allowing its own repression.
Laboratoire Dynamique du Génome et Evolution, Institut Jacques Monod, UMR7592, CNRS-Universités Paris 6 et 7, 2 Place Jussieu, 75251 Paris Cedex 05, France. ronsseray@ijm.jussieu.fr
Stéphane
S
Ronsseray
Thibaut
T
Josse
Antoine
A
Boivin
Dominique
D
Anxolabéhère
D000818:Animals; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins / Q000235:genetics; D005260:Female; D020868:Gene Silencing; D008297:Male; D009687:Nuclear Proteins / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics; D016615:Telomere / Q000235:genetics*; D019076:Transgenes / Q000235:genetics*
D029721:Drosophila Proteins; D009687:Nuclear Proteins; C092281:PSI protein, Drosophila; D016601:RNA-Binding Proteins