Interaction of the Chlamydia trachomatis histone H1-like protein (Hc1) with DNA and RNA causes repression of transcription and translation in vitro

Mol Microbiol. 1994 Mar;11(6):1085-98. doi: 10.1111/j.1365-2958.1994.tb00385.x.


The 18 kDa histone H1-like protein from Chlamydia trachomatis (Hc1) is a DNA-binding protein thought to be involved in condensation of the chlamydial chromosome during late stages in the chlamydial life cycle. Expression of Hc1 in Escherichia coli results in an overall relaxation of DNA and severely affects DNA, RNA and protein synthesis. We have analysed the interaction of Hc1 with single-stranded DNA and RNA by Southwestern and Northwestern blotting. Furthermore, we show that purified, recombinant Hc1 dramatically affects transcription and translation in vitro at physiologically relevant concentrations. These results were found to coincide with the formation of condensed Hc1-DNA and Hc1-RNA complexes as revealed by agarose gel electrophoresis and electron microscopy. The implications of these results for possible functions of Hc1 in vivo are discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chlamydia trachomatis / genetics*
  • Chlamydia trachomatis / metabolism
  • DNA, Bacterial / metabolism*
  • DNA, Single-Stranded / metabolism
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • DNA-Binding Proteins / ultrastructure
  • Escherichia coli / physiology
  • Macromolecular Substances
  • Protein Binding
  • Protein Biosynthesis
  • Protein Synthesis Inhibitors / metabolism
  • Protozoan Proteins*
  • RNA, Bacterial / metabolism*
  • RNA, Bacterial / ultrastructure
  • RNA-Binding Proteins*
  • Recombinant Proteins / metabolism
  • Repressor Proteins / metabolism*
  • Repressor Proteins / ultrastructure
  • Transcription, Genetic


  • DNA, Bacterial
  • DNA, Single-Stranded
  • DNA-Binding Proteins
  • Hc1 protein, Chlamydia trachomatis
  • Macromolecular Substances
  • Protein Synthesis Inhibitors
  • Protozoan Proteins
  • RNA, Bacterial
  • RNA-Binding Proteins
  • Recombinant Proteins
  • Repressor Proteins