The 5' untranslated region of the I factor, a long interspersed nuclear element-like retrotransposon of Drosophila melanogaster, contains an internal promoter and sequences that regulate expression.
The I-R system of hybrid dysgenesis in Drosophila melanogaster is controlled by a long interspersed nuclear element-like retroposon, the I factor. Transposition of the I factor occurs at a high frequency only in the ovaries of females produced by crossing males of inducer strains that contain functional I factors with females of reactive strains that lack them. In this study, the 5' untranslated region of the I factor was joined to the chloramphenicol acetyltransferase gene, and activity was assayed in transfected D. melanogaster tissue culture cells and transformed flies. The results have identified a promoter that lies within the first 186 pb of the I factor. Deletion analysis shows that nucleotides +1 to +40 are sufficient for high promoter activity and accurate transcription initiation. This region contains sequences that are found in a class of RNA polymerase II promoters that lack both a TATA box and CpG-rich motifs. In transformed flies, high levels of expression from nucleotides +1 to +186 are confined to the ovaries of reactive females, suggesting that the promoter is involved in the tissue and cytotype specificity of transposition.
McLean
C
C
Institute of Cell and Molecular Biology, University of Edinburgh, Scotland.
Bucheton
A
A
Finnegan
D J
DJ
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004247:DNA; D004251:DNA Transposable Elements; D004331:Drosophila melanogaster / Q000235:genetics*; D005260:Female; D005786:Gene Expression Regulation; D007438:Introns; D008297:Male; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D014170:Transformation, Genetic
D004251:DNA Transposable Elements; D004247:DNA