Eimeria tenella: Identification of secretory and surface proteins from expressed sequence tags

• Published in: Experimental parasitology Vol. 111; no. 1; pp. 14 - 23
• Main Authors: Klotz, Christian, Marhöfer, Richard J., Selzer, Paul M., Lucius, Richard, Pogonka, Thomas
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01-09-2005; Elsevier
• Subjects: 2,3,5-triphenylterazolium chloride; accession number; AMA1; Amino Acid Sequence; amino acid sequences; Animals; apical membrane protein 1; Apicomplexa; Apicomplexa - chemistry; Apicomplexa - genetics; base pair; beta-Fructofuranosidase - genetics; beta-Fructofuranosidase - metabolism; Biological and medical sciences; Chicken; Cluster Analysis; Coccidia; complementary DNA; Consensus Sequence; contig number; DNA, Complementary - chemistry; DNA, Complementary - isolation & purification; Eimeria tenella; Eimeria tenella - chemistry; Eimeria tenella - enzymology; Eimeria tenella - genetics; endoplasmic reticulum; EST; expressed sequence tag; Expressed Sequence Tags; Fundamental and applied biological sciences. Psychology; genetic complementation; Host–parasite interaction; In silico analysis; in silico expression analysis; Lag1; Life cycle. Host-agent relationship. Pathogenesis; longevity assurance homolog 1; Membrane Proteins - chemistry; Membrane Proteins - genetics; Membrane Proteins - isolation & purification; MIC; micronema protein; nucleotide sequences; outer membrane proteins; PAP; phosphatidic acid phosphatase; protein secretion; Protein Sorting Signals - genetics; Protozoa; Protozoan Proteins - chemistry; Protozoan Proteins - genetics; Protozoan Proteins - isolation & purification; Protozoan Proteins - secretion; recombinant fusion proteins; reverse transcribed-polymerase chain reaction; RNA, Protozoan - genetics; RT-PCR; secreted protein with altered thrombospondin repeat; Secretory proteins; sequence analysis; Sequence Homology; sequence retrieval system; signal peptide; SPATR; SRS; Surface proteins; thrombospondin type 1 repeat; thrombospondin-related adhesive protein; Transfection; TRAP; TSR; TTC; Apicomplexa; AMA1; TTC; MIC; EST; In silico analysis; Eimeria tenella; Coccidia; TRAP; CN; AN; ER; bp; Expressed sequence tags; TSR; SPATR; SRS; RT-PCR; Host–parasite interaction; Chicken; Surface proteins; Lag1; Secretory proteins; PAP; Protozoa; Host parasite relation; Parasite; Vertebrata; Host-parasite interaction; Secretory protein; Aves; Expressed sequence tag
• ISSN: 0014-4894; 1090-2449
• DOI: 10.1016/j.exppara.2005.04.005

To identify new vaccine candidates,
Eimeria tenella expressed sequence tags (ESTs) from public databases were analysed for secretory molecules with an especially developed automated in silico strategy termed DNAsignalP. A total of 12,187 ESTs were clustered into 2881 contigs followed by a blastx search, which resulted in a significant number of
E. tenella contigs with homologies to entries in public databases. Amino acid sequences of appropriate homologous proteins were analysed for the occurrence of an N-terminal signal sequence using the algorithm signalP. The resulting list of 84 entries comprised 51 contigs whose deduced proteins showed homologies to proteins of apicomplexan parasites. Based on function or localisation, we selected candidate proteins classified as (i) secreted proteins of Apicomplexa parasites, (ii) secreted enzymes, and (iii) transport and signalling proteins. To verify our strategy experimentally, we used a functional complementation system in yeast. For five selected candidate proteins we found that these were indeed secreted. Our approach thus represents an efficient method to identify secretory and surface proteins out of EST databases.