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Cyclin A is required for the onset of DNA replication in mammalian fibroblasts

F Girard1, U Strausfeld, A Fernandez

  • 1Cell Biology Unit, CRBM, CNRS-INSERM, Montpellier, France.

Cell
|December 20, 1991
PubMed

Insights

Cyclin A protein is essential for DNA replication in mammalian cells. Inhibiting its synthesis or function halts DNA synthesis, but adding it back restores the process.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • Cyclin A protein is synthesized and enters the nucleus at the start of S phase in mammalian fibroblasts.
  • The precise role of Cyclin A in DNA replication control is under investigation.

Purpose of the Study:

  • To investigate the role of Cyclin A in the control of DNA replication in mammalian cells.
  • To determine if Cyclin A is a key regulator of DNA synthesis.

Main Methods:

  • Microinjection of plasmids encoding antisense cyclin A cDNA into G1 phase cells.
  • Microinjection of affinity-purified anti-cyclin A antibodies into G1 phase cells.
  • Assessing nuclear staining for Cyclin A and monitoring DNA synthesis.
  • Reintroduction of purified human cyclin A protein into inhibited cells.

Main Results:

  • Inhibition of cyclin A synthesis or activity abolished nuclear cyclin A staining and inhibited DNA synthesis.
  • Control antisense vectors, including antisense cyclin B, did not produce similar effects.
  • Reintroducing cyclin A protein reversed the inhibition of DNA synthesis.

Conclusions:

  • Cyclin A plays a critical role in the regulation of DNA replication in mammalian cells.
  • These findings highlight Cyclin A as a key target for controlling cell cycle progression and DNA synthesis.

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