Two regions in mdg1 mobile element's body can specifically bind nuclear proteins of Drosophila melanogaster, as demonstrated by the method of retention of DNA-protein complexes of nitrocellulose filters. The first region is situated in the 5'-end part of mdg1, 1 kb downstream the site of initiation of transcription and contains long oligo (A) blocks (from 14 to 30 nucleotides) in the coding chain. The second region is localized near the 3'-LTR and consists of tandem 14-nucleotide repeats and a palindrome, destruction of which leads to weaker binding.
View Article and Find Full Text PDFThe mdg4 (gypsy) mobile element of Drosophila contains two closely situated regions binding to proteins from nuclear extracts. One of these is an imperfect palindrome having homology with the lac operator of Escherichia coli, the other contains a reiterated sequence (5'PyPuTCTGCATACTPyPy) homologous to the octamer which is the core of many enhancers and upstream promoter elements. The transient expression of deletion mutants has shown that these DNA regions are negative and positive regulators, respectively, of mdg4 transcription.
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