An Entamoeba cysteine peptidase specifically expressed during encystation.

Abstract

Protozoan parasites of the genus Entamoeba possess a considerable number of cysteine peptidases (CPs), the function of most of these molecules for amoeba biology needs to be established. In order to determine whether CPs may play a role during Entamoeba stage conversion from trophozoites into cysts and vice versa, expression of cp genes was analysed in the reptilian parasite Entamoeba invadens, a model organism for studying Entamoeba cyst development. By homology search, 28 papain-like cp genes were identified in public E. invadens genome databases. For eight of these genes the expression profiles during stage conversion was determined. By Northern blot analysis, transcripts for eicp-a9, -b7, -b8 and -c2, respectively, were detected neither in trophozoites or cysts nor at any of the point of times analysed during stage conversion. On the other hand, eicp-a5 is constitutively expressed during all developmental stages, whereas eicp-a3 and eicp-a11, respectively, are trophozoite-specific. Only eicp-b9 was found to be cyst-specific as it is expressed exclusively 18 to 28 h after cyst induction. Cyst-specific expression was confirmed by immunofluorescence microscopy of the corresponding protein EiCP-B9. In immature cysts, the molecule is located in structures that accumulate near the cyst wall, but which are uniformly distributed in mature cysts. The precise function of EiCP-B9 during Entamoeba encystation remains to be determined. However, colocalisation studies with an Entamoeba marker for autophagosomes suggest that EiCP-B9 is not associated with Entamoeba autophagy.

• Authors: Frank Ebert, Anna Bachmann, Kumiko Nakada-Tsukui, Ina Hennings, Babette Drescher, Tomoyoshi Nozaki, Egbert Tannich, Iris Bruchhaus
• Journal: Parasitology international (Parasitol Int) Vol. 57 Issue 4 Pg. 521-4 (Dec 2008) ISSN: 1383-5769 [Print] Netherlands
• PMID: 18723116 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Protozoan Proteins
• Cysteine Endopeptidases

Topics

• Animals
• Cysteine Endopeptidases (genetics, metabolism)
• Entamoeba (classification, enzymology, genetics, growth & development)
• Fluorescent Antibody Technique
• Gene Expression Regulation, Developmental
• Life Cycle Stages
• Protozoan Proteins (genetics, metabolism)
• Trophozoites (enzymology)