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Modulation of Sp1 activity by a cyclin A/CDK complex

E Haidweger1, M Novy, H Rotheneder

  • 1Institute of Medical Biochemistry, Division of Molecular Biology, Vienna Biocenter, University of Vienna, Vienna, A-1030, Austria.

Journal of Molecular Biology
|March 10, 2001
PubMed

Insights

Sp1 transcription factors interact with cyclin A, a cell cycle regulator. Phosphorylation by cyclin A/CDK complexes influences Sp1

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • Sp1 family transcription factors regulate gene expression.
  • These factors are involved in various cellular pathways.
  • Their activity can be modulated to control gene transcription.

Purpose of the Study:

  • To investigate the association between Sp1 and cell cycle regulators.
  • To determine the role of cyclin A in Sp1 activity.
  • To elucidate the mechanism of Sp1 regulation during cell growth.

Main Methods:

  • Co-immunoprecipitation assays to detect protein interactions.
  • In vitro phosphorylation assays.
  • Reporter gene assays to measure transcriptional activity.
  • Electrophoretic mobility shift assays (EMSA) to assess DNA-binding ability.

Main Results:

  • Sp1 directly interacts with cyclin A.
  • Sp1 is phosphorylated by a cyclin A-associated kinase.
  • Cyclin A overexpression enhances Sp1-driven reporter gene expression.
  • Inhibition of CDK2/CDC2 activity reduces Sp1 DNA-binding and reporter gene expression.

Conclusions:

  • Sp1 interacts with cyclin A and is regulated by cyclin A/CDK complexes.
  • Phosphorylation by cyclin A/CDK affects Sp1's DNA-binding ability.
  • This interaction plays a role in regulating Sp1 transcriptional activity during cell growth and cell cycle progression.

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