The Entamoeba histolytica Ehcp112 gene has a distal and weak promoter

Exp Parasitol. 2005 Jul;110(3):286-91. doi: 10.1016/j.exppara.2005.03.003. Epub 2005 Apr 9.

Abstract

Ehcp112 encodes the Entamoeba histolytica EhCP112 cysteine protease that is part of the EhCPADH complex. By in silico analysis we identified putative transcription factor-binding sites along 837 bp upstream the Ehcp112 gene ATG codon. A TATA-like motif (TATATAAA) was located at -36 to -29 bp, a GAAC box (GAACC) was found at -10 to -14 bp and an Inr sequence (TTCAAC) at -8 to -2 bp. These tripartite promoter elements are in non-canonical positions, downstream the transcription initiation site (-280 bp). We cloned four Ehcp112 promoter fragments in pBSCAT-ACT plasmid to obtain pI (355 bp), pII (681 bp), pIII (833 bp), and pIV (554 bp) constructs. In transfected trophozoites, only pIII drove CAT activity with 44% efficiency in relation to actin promoter activity. Our results showed the presence of a distal and weak promoter in the Ehcp112 gene. The active DNA region is inside the open reading frame of the Ehrab B gene, suggesting that expression of both genes could be coordinately regulated.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Chloramphenicol O-Acetyltransferase / genetics
  • Cysteine Endopeptidases / genetics*
  • DNA, Protozoan / chemistry
  • Entamoeba histolytica / enzymology
  • Entamoeba histolytica / genetics*
  • Gene Expression Regulation
  • Molecular Sequence Data
  • Plasmids / chemistry
  • Promoter Regions, Genetic / genetics*
  • Promoter Regions, Genetic / physiology
  • Transcriptional Activation / physiology
  • Transfection

Substances

  • DNA, Protozoan
  • Chloramphenicol O-Acetyltransferase
  • Cysteine Endopeptidases