umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Mouse ribonucleotide reductase R2 protein: A new target for anaphase-promoting complex-Cdh1-mediated proteolysis.
Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
2003 (English)In: Proc. Natl. Acad. Sci. U S A., Vol. 100, no 7, 3925-3929 p.Article in journal (Refereed) Published
Place, publisher, year, edition, pages
2003. Vol. 100, no 7, 3925-3929 p.
Identifiers
URN: urn:nbn:se:umu:diva-4115OAI: oai:DiVA.org:umu-4115DiVA: diva2:143086
Available from: 2003-06-04 Created: 2003-06-04 Last updated: 2011-03-30Bibliographically approved
In thesis
1. Regulation of the Expression of Mouse Ribonucleotide Reductase Small Subunit at the Levels of Transcription and Protein Degradation
Open this publication in new window or tab >>Regulation of the Expression of Mouse Ribonucleotide Reductase Small Subunit at the Levels of Transcription and Protein Degradation
2003 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Deoxyribonucleic acid (DNA) carries all the genetic information of a cell. Ribonucleotide reductase (RNR) provides balanced pools of all four dNTPs, the building blocks of DNA. These building blocks are needed during DNA synthesis and repair. A failure in the control of the dNTP levels and/or their relative amounts leads to cell death or genetic abnormalities. Because of its central role in dNTP metabolism, RNR is highly regulated on multiple levels.

The active RNR enzyme consists of two non-identical subunits called proteins R1 and R2. In mammalian cells, during an unperturbed cell cycle, the activity of RNR is highest during S and G2 phases. This is achieved by de novo synthesis of the limiting R2 protein at the onset of S phase, and by controlled degradation of the R2 protein during mitosis.

This thesis deals with both the S phase-specific transcription of the mouse R2 gene, and the M phase-specific degradation of the mouse R2 protein. Sequence comparison of the mouse R2 promoter to human and guinea pig R2 promoters revealed some conserved elements. These putative regulatory elements were tested in both in vitro and in vivo transcription assays. We demonstrated that the previously identified,

NF-Y binding CCAAT box is essential for high-level expression from the R2 promoter, but not for its S phase specificity. In addition, the conserved TATA box is dispensable both for basal and S phase-specific R2 transcription as long as the first 17 basepairs of the 5’ untranslated region are present. However, if this 5’ untranslated region is absent, the TATA box is needed for correct initiation of transcription.

Focusing on the S phase specificity of the R2 gene expression, we demonstrated that the S phase-specific activity of the mouse R2 promoter is dependent on a protein-binding region located ~500 basepairs upstream of the transcription start site and an E2F binding site close to the transcription start site. Deletion of the upstream activating region results in an inactive promoter. In contrast, mutation of the E2F site leads to premature promoter activation in G1 and increased overall promoter activity. However, if the activating mutation of the E2F site is combined with mutation of the upstream activating region, the promoter becomes inactive. These results suggest that the E2F-dependent regulation is important but not sufficient for cell-cycle specific R2 transcription, and that the upstream activating region is crucial for the overall R2 promoter activity.

In our studies of the M phase-specific R2 degradation, we found that it is dependent on a KEN sequence in the N-terminus of the R2 protein, recognized by the Cdh1-APC complex. Mutating the KEN box stabilizes the R2 protein during mitosis and G1 phase.

In summary, these studies further extend our understanding of the regulation of the limiting R2 subunit of the enzyme ribonucleotide reductase. The S phase-specific transcription of the R2 gene and the M phase-specific degradation of the R2 protein may serve as important

mechanisms to protect the cell against unscheduled DNA synthesis.

Place, publisher, year, edition, pages
Umeå: Medicinsk kemi och biofysik, 2003. 34 p.
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 847
Keyword
Molecular biology, ribonucleotide reductase, transcription, protein degradation, cell cycle, Molekylärbiologi
National Category
Biochemistry and Molecular Biology
Research subject
Medical Cell Biology
Identifiers
urn:nbn:se:umu:diva-32 (URN)91-7305-468-2 (ISBN)
Public defence
2003-06-13, KB3A9, KBC-huset, Umeå, 13:00 (English)
Opponent
Supervisors
Available from: 2003-06-04 Created: 2003-06-04 Last updated: 2015-01-19Bibliographically approved

Open Access in DiVA

No full text

Other links

http://dx.doi.org/10.1073/pnas.0330774100

Authority records BETA

Chabes, Anna LenaThelander, Lars

Search in DiVA

By author/editor
Chabes, Anna LenaThelander, Lars
By organisation
Department of Medical Biochemistry and Biophysics

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 76 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf