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pubmed:abstractText |
We find DNA fragments attached to the nuclear scaffold (SARs) both 5' and 3' of three Drosophila genes, defining looped domains ranging from 4.5 to 13 kb. For the two-promoter-containing gene Adh (alcohol dehydrogenase), we find two upstream and two downstream SARs. For Sgs-4, the 5' SAR covers 866 bp immediately upstream of the transcript, and in the case of fushi tarazu, the 5' SAR is found on a small fragment 4.8 kb upstream of the start of transcription. These four upstream scaffold-attached fragments comap with enhancer-like regulatory sequences. Sequence analysis of five upstream SARs reveals clusters of sequences closely related to the cleavage consensus of topoisomerase II, several copies of a specific 10 bp A-rich sequence (AATAAATCAAA), and another 10 bp T-rich stretch.
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