X-irradiation activates the Drosophila 1731 retrotransposon LTR and stimulates secretion of an extracellular factor that induces the 1731-LTR transcription in nonirradiated cells.
Using constructs expressing the reporter gene under the control of the entire or deleted long terminal repeats (LTRs) of 1731, a Drosophila melanogaster retrotransposable element, we show that 1731-LTR is activated by X-irradiation in a dose- and time-dependent manner, and that a sequence located in the U3 region of these LTRs is required. The cis-acting element conferring X-responsiveness shows similarities to kappa B (kappa B)-like binding sequence. In response to X-irradiation, S2 Drosophila cells produced an extracellular factor which activates the 1731-LTR in nonirradiated cells. This factor was detected both when transfected cells were cocultured with inducing cells and when a conditioned medium taken from irradiated cultures was added.
Institut de Chimie Biologique, Université de Provence, Marseille, France.
E
E
Faure
M
M
Best-Belpomme
S
S
Champion
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D017077:Culture Media, Conditioned; D004247:DNA / Q000235:genetics; D004331:Drosophila melanogaster / Q000235:genetics* / Q000528:radiation effects*; D016328:NF-kappa B / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid / Q000528:radiation effects*; D018626:Retroelements / Q000528:radiation effects*; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic / Q000528:radiation effects; D014162:Transfection
D017077:Culture Media, Conditioned; D016328:NF-kappa B; D018626:Retroelements; D004247:DNA; D015500:Chloramphenicol O-Acetyltransferase