Alternative DNA-protein interactions in variable-length internucleosomal regions associated with Drosophila Adh distal promoter expression.
Chromatin at the Drosophila Adh distal promoter displays an ordered but different conformation in different cell types as detected by a modified exonuclease protection assay and accessibility to endonucleases. In cells not transcribing Adh (ADH-) sequences between -40 to +30 of the distal RNA initiation site exist as a DNA linker between positioned nucleosomes, and appear to interact with a specific DNA-binding protein. In contrast, a longer linker DNA, from -140 to +30, is bound in a multi-protein transcription initiation complex in cells that specifically transcribe the distal (adult) ADH RNA (ADH+A). These DNA-protein interactions can account for a localized open chromatin structure at the distal promoter in ADH+A cells. The observed mutually exclusive patterns of DNA-protein interactions in the linkers of different ADH cell types between -40 to +30 suggest a model for organizing alternative chromatin structure associated with gene regulation. Two DNA binding proteins, one being a TATA box binding factor, compete for overlapping sites to allow either assembly of a transcription initiation complex and transcription, or positioning of nucleosomes for stable repression.
Ewel
A
A
Department of Biology, University of Rochester, NY 14627.
Jackson
J R
JR
Benyajati
C
C
D000426:Alcohol Dehydrogenase / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D002843:Chromatin / Q000378:metabolism; D004247:DNA / Q000235:genetics* / Q000378:metabolism; D003850:Deoxyribonuclease I; D004330:Drosophila / Q000201:enzymology / Q000235:genetics*; D005092:Exonucleases; D015870:Gene Expression; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D009693:Nucleic Acid Hybridization; D009707:Nucleosomes / Q000378:metabolism*; D009710:Nucleotide Mapping; D011401:Promoter Regions, Genetic; D015183:Restriction Mapping
D002843:Chromatin; D009687:Nuclear Proteins; D009707:Nucleosomes; D004247:DNA; D000426:Alcohol Dehydrogenase; D005092:Exonucleases; D003850:Deoxyribonuclease I