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DNA protein interactions at the rRNA of Saccharomyces cerevisiae.
Ital J Biochem. 2007 Jun; 56(2):81-90.IJ

Abstract

The rDNA cluster is the genetic locus encoding the ribosomal RNAs and physically defines where ribosomes begin to be assembled. In the yeast Saccharomyces cerevisiae, the highly repetitive structure of this locus makes it a very interesting target for studies about genome stability, chromatin-mediated transcriptional silencing and progression of aging. In fact, recombination among the repeated units is suppressed in a WT cell. Moreover, when genes transcribed by RNA polymerase II are inserted in the rDNA cluster, their transcription is silenced. Finally, the formation of rDNA minicircles (ERCs) has been shown to be one of the causes of aging in yeast. DNA topoisomerase I have been shown to suppress recombination specifically at the rDNA of S.cerevisiae. Moreover, also the chromatin structure of this locus is affected in a top1 strain, because rDNA specific transcriptional silencing is abolished. Nonetheless, the molecular basis of how this enzyme interferes with these functions is yet unknown. Here are reported results obtained by in vivo studies of DNA protein interactions occurring on the rDNA locus. The analyses include a fine mapping of nucleosome positioning; RNA polymerase I transcription factors and DNA topoisomerase I cleavage sites. Important conclusions can be drawn: i) nucleosome positioning in the Non Transcribed Spacer is not affected by RNA polymerase I transcription; ii) the RNA polymerase I transcription factors bind DNA in vivo with a defined hierarchy; iii) the DNA topoisomerase I cleaves the NTS in very specific sites, but cleavage is not induced by RNA polymerase I transcription. These in vivo studies help to characterize the molecular basis of important phenomena as the transcriptional silencing and genome stability in yeast.

Authors+Show Affiliations

Dipartimento di Genetica e Biologia Molecolare, Università di Roma La Sapienza.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Review

Language

eng

PubMed ID

17722648

Citation

Cioci, Francesco, et al. "DNA Protein Interactions at the rRNA of Saccharomyces Cerevisiae." The Italian Journal of Biochemistry, vol. 56, no. 2, 2007, pp. 81-90.
Cioci F, Di Felice F, Chiani F, et al. DNA protein interactions at the rRNA of Saccharomyces cerevisiae. Ital J Biochem. 2007;56(2):81-90.
Cioci, F., Di Felice, F., Chiani, F., & Camilloni, G. (2007). DNA protein interactions at the rRNA of Saccharomyces cerevisiae. The Italian Journal of Biochemistry, 56(2), 81-90.
Cioci F, et al. DNA Protein Interactions at the rRNA of Saccharomyces Cerevisiae. Ital J Biochem. 2007;56(2):81-90. PubMed PMID: 17722648.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - DNA protein interactions at the rRNA of Saccharomyces cerevisiae. AU - Cioci,Francesco, AU - Di Felice,Francesca, AU - Chiani,Francesco, AU - Camilloni,Giorgio, PY - 2007/8/29/pubmed PY - 2007/9/15/medline PY - 2007/8/29/entrez SP - 81 EP - 90 JF - The Italian journal of biochemistry JO - Ital J Biochem VL - 56 IS - 2 N2 - The rDNA cluster is the genetic locus encoding the ribosomal RNAs and physically defines where ribosomes begin to be assembled. In the yeast Saccharomyces cerevisiae, the highly repetitive structure of this locus makes it a very interesting target for studies about genome stability, chromatin-mediated transcriptional silencing and progression of aging. In fact, recombination among the repeated units is suppressed in a WT cell. Moreover, when genes transcribed by RNA polymerase II are inserted in the rDNA cluster, their transcription is silenced. Finally, the formation of rDNA minicircles (ERCs) has been shown to be one of the causes of aging in yeast. DNA topoisomerase I have been shown to suppress recombination specifically at the rDNA of S.cerevisiae. Moreover, also the chromatin structure of this locus is affected in a top1 strain, because rDNA specific transcriptional silencing is abolished. Nonetheless, the molecular basis of how this enzyme interferes with these functions is yet unknown. Here are reported results obtained by in vivo studies of DNA protein interactions occurring on the rDNA locus. The analyses include a fine mapping of nucleosome positioning; RNA polymerase I transcription factors and DNA topoisomerase I cleavage sites. Important conclusions can be drawn: i) nucleosome positioning in the Non Transcribed Spacer is not affected by RNA polymerase I transcription; ii) the RNA polymerase I transcription factors bind DNA in vivo with a defined hierarchy; iii) the DNA topoisomerase I cleaves the NTS in very specific sites, but cleavage is not induced by RNA polymerase I transcription. These in vivo studies help to characterize the molecular basis of important phenomena as the transcriptional silencing and genome stability in yeast. SN - 0021-2938 UR - https://www.unboundmedicine.com/medline/citation/17722648/DNA_protein_interactions_at_the_rRNA_of_Saccharomyces_cerevisiae_ L2 - https://antibodies.cancer.gov/detail/CPTC-TOP1-1 DB - PRIME DP - Unbound Medicine ER -