The upstream limit of nuclease-sensitive chromatin in Dictyostelium rRNA genes neighbors a topoisomerase I-like cluster

Bettler, B. and Ness, P. J. and Schmidlin, S. and Parish, R. W.. (1988) The upstream limit of nuclease-sensitive chromatin in Dictyostelium rRNA genes neighbors a topoisomerase I-like cluster. Journal of molecular biology, Vol. 204, H. 3. pp. 549-559.

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Official URL: http://edoc.unibas.ch/dok/A5262308

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In the chromatin of Dictyostelium ribosomal RNA (rRNA) genes, the coding and upstream flanking regions are sensitive to endonucleases. This sensitivity stops about 2.3 x 10(3) bases upstream from the transcription start, at a point we call the structural boundary. Upstream from the boundary an 850 base-pair region is strongly protected against micrococcal nuclease cleavage, particularly in rapidly transcribing vegetative cells, and upstream from this the pattern of nuclease protection suggests that positioned nucleosomes are present. On the gene side of the structural boundary nucleosomes are known to be absent in vegetative cells but present in differentiating slug cells where the rRNA synthesis rate is lower. We show that in slugs these nucleosomes are randomly distributed, in contrast to those upstream from the boundary. Close to the gene side of the boundary is a duplication of the putative promoter located 29 base-pairs distant from four clustered topoisomerase I recognition sequences, which are cleaved by endogenous topoisomerase I-like activity. An additional topoisomerase I recognition sequence found upstream from the structural boundary is not cleaved in chromatin. The possible significance of these sequences and structures in transcription is discussed.
Faculties and Departments:03 Faculty of Medicine > Departement Biomedizin > Division of Physiology > Molecular Neurobiology Synaptic Plasticity (Bettler)
UniBasel Contributors:Bettler, Bernhard
Item Type:Article, refereed
Article Subtype:Research Article
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:22 Mar 2012 14:23
Deposited On:22 Mar 2012 13:34

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