Domesticated P elements in the Drosophila montium species subgroup have a new function related to a DNA binding property.
Molecular domestication of a transposable element is defined as its functional recruitment by the host genome. To date, two independent events of molecular domestication of the P transposable element have been described: in the Drosophila obscura species group and in the Drosophila montium species subgroup. These P neogenes consist of stationary, nonrepeated sequences, potentially encoding 66-kDa repressor-like (RL) proteins. Here we investigate the function of the montium P neogenes. We provide evidence for the presence of RL proteins in two montium species (D. tsacasi and D. bocqueti) specifically expressed in adult and larval brain and gonads. We tested the hypothesis that the montium P neogenes' function is related to the repression of the transposition of distantly related mobile P elements which coexist in the genome. Our results strongly suggest that the montium P neogenes are not recruited to downregulate the P element transposition. Given that all the proteins encoded by mobile or stationary P homologous sequences show a strong conservation of the DNA binding domain, we tested the capacity of the RL proteins to bind DNA in vivo. Immunostaining of polytene chromosomes in D. melanogaster transgenic lines strongly suggests that montium P neogenes encode proteins that bind DNA in vivo. RL proteins show multiple binding to the chromosomes. We suggest that the property recruited in the case of the montium P neoproteins is their DNA binding property. The possible functions of these neogenes are discussed.
Reiss
Daphné
D
Laboratoire Dynamique du Génome et Evolution, Institut Jacques Monod, UMR7592, CNRS-Universités Paris 6 et 7, 2 place Jussieu, 75251 Paris Cedex 05, France.
Nouaud
Danielle
D
Ronsseray
Stéphane
S
Anxolabéhère
Dominique
D
D000818:Animals; D001921:Brain / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism; D004247:DNA / Q000378:metabolism*; D004251:DNA Transposable Elements / Q000235:genetics*; D004330:Drosophila / Q000145:classification* / Q000235:genetics*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D019143:Evolution, Molecular; D005091:Exons / Q000235:genetics; D005260:Female; D006066:Gonads / Q000378:metabolism; D019476:Insect Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D007814:Larva / Q000378:metabolism; D008297:Male; D016254:Mutagenesis, Insertional; D010053:Ovary / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D013737:Testis / Q000166:cytology; D014158:Transcription, Genetic
D002843:Chromatin; D004251:DNA Transposable Elements; D029721:Drosophila Proteins; D019476:Insect Proteins; D004247:DNA