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Chromatin structure of a hyperactive secretory protein gene (in Balbiani ring 2) of Chironomus.
Author(s) -
Widmer R.M.,
Lucchini R.,
Lezzi M.,
Meyer B.,
Sogo J.M.,
Edström J.E.,
Koller T.
Publication year - 1984
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1984.tb02022.x
Subject(s) - biology , micrococcal nuclease , chromatin , microbiology and biotechnology , gene , nucleosome , rna polymerase , dna , gene expression , rna , restriction enzyme , genetics
We examined the chromatin structure of a Balbiani ring (secretory protein gene) in the salivary glands of Chironomus larvae in its hyperactive state after stimulation with pilocarpine. For the inactive state of the gene an established tissue culture cell line, not expressing the gene, was used. Electron microscopy showed an RNA polymerase density of approximately 38/microns. Micrococcal nuclease digestion of purified nuclei followed by DNA transfer and hybridization revealed a smear with no recognizable discrete DNA fragments. Without pilocarpine stimulation a faint nucleosomal repeat was superimposed upon the smear, and in tissue culture cells a clear nucleosomal repeat was revealed. The restriction enzyme XbaI, which has a 6‐bp recognition sequence, cut the gene in the hyperactive chromatin state, but not in its inactive conformation. The combined results are best explained by the absence of most of the nucleosomes in this hyperactive RNA polymerase II transcribed gene.