Mechanism of cyst specific protein 21 mRNA induction during Acanthamoeba differentiation

Biochim Biophys Acta. 2004 Apr 1;1691(1):23-31. doi: 10.1016/j.bbamcr.2003.11.005.


The Acanthamoeba cyst specific protein 21 (CSP21) gene is tightly repressed in growing cells and highly induced early during differentiation into a dormant cyst. This increase is mediated by the rate of transcription of the CSP21 gene as determined by nuclear run-on assays. The promoter region of the CSP21 gene was analyzed by transcript start site mapping and in vitro transcription of wild-type or mutant templates, using extracts from growing cells. A sequence located 3' to a modified TATA box completely inhibits transcription and removal of this region permits robust transcription utilizing a start site approximately 35 base pairs downstream of the TATA box. Sequences 5' to the TATA box had no effect on transcription, suggesting that anti-repression is the only mechanism required for CSP21 induction. Fractionation of nuclear extracts yielded a fraction capable of transcription from the CSP21 promoter, and a fraction containing a promoter-specific repressing activity. Anti-repression may thus be a major mechanism regulating differentiation or maintenance of the proliferative cycle in Acanthamoeba.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acanthamoeba / genetics*
  • Acanthamoeba / growth & development
  • Animals
  • Genes, Regulator
  • Promoter Regions, Genetic
  • Protozoan Proteins / genetics*
  • RNA, Messenger / biosynthesis
  • TATA Box
  • Transcription Initiation Site
  • Transcription, Genetic*
  • Untranslated Regions


  • CSP21 protein, Acanthamoeba castellanii
  • Protozoan Proteins
  • RNA, Messenger
  • Untranslated Regions