Ectopic expression of truncated Sp1 transcription factor prolongs the S phase and reduces the growth rate

Anticancer Res. Mar-Apr 2000;20(2A):661-7.


The role of the transcription factor Sp1 in cell growth and survival was investigated by induced expression of its DNA-binding C-terminal fragment. Transfection of a constitutively expressed Sp1-170C plasmid construct into HeLa cells failed to produce viable clones, suggesting that this peptide interferes with cell growth. However, transfection with the muristerone A-inducible vector system produced four clones with low levels of expression of Sp1-170C. Muristerone A transiently induced higher levels of Sp1-170C, and this was accompanied by a reduced growth rate and prolongation of the S phase of the cell cycle. This is the first report that a dominant negative Sp1 can affect the cell cycle.

MeSH terms

  • Base Sequence
  • Cell Cycle*
  • Cell Division / drug effects
  • Ecdysterone / analogs & derivatives*
  • Ecdysterone / pharmacology
  • HeLa Cells
  • Humans
  • Kinetics
  • Recombinant Proteins / metabolism
  • Restriction Mapping
  • Reverse Transcriptase Polymerase Chain Reaction
  • S Phase / drug effects
  • Sp1 Transcription Factor / genetics*
  • Sp1 Transcription Factor / metabolism*
  • Transfection


  • Recombinant Proteins
  • Sp1 Transcription Factor
  • muristerone A
  • Ecdysterone