Gene Discovery by EST Sequencing in Toxoplasma gondiiReveals Sequences Restricted to the Apicomplexa
- James W. Ajioka1,
- John C. Boothroyd2,
- Brian P. Brunk3,
- Adrian Hehl2,
- Ledeana Hillier4,
- Ian D. Manger2,
- Marco Marra4,
- G. Christian Overton3,
- David S. Roos5,
- Kiew-Lian Wan1,6,
- Robert Waterston4, and
- L. David Sibley7,8
- 1Department of Pathology, Cambridge University, Cambridge, CB21QP UK; 2Department of Microbiology and Immunology, Stanford University, Stanford, California 94305 USA; 3Center for Bioinformatics, Department of Genetics, 5Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104 USA; 4Genome Sequencing Center, Department of Genetics, 7Department of Molecular Microbiology, Washington University, St. Louis, Missouri 63110 USA; 6Department of Biochemistry, University Kebansaan, 43600 Malaysia
Abstract
To accelerate gene discovery and facilitate genetic mapping in the protozoan parasite Toxoplasma gondii, we have generated >7000 new ESTs from the 5′ ends of randomly selected tachyzoite cDNAs. Comparison of the ESTs with the existing gene databases identified possible functions for more than 500 new T. gondiigenes by virtue of sequence motifs shared with conserved protein families, including factors involved in transcription, translation, protein secretion, signal transduction, cytoskeleton organization, and metabolism. Despite this success in identifying new genes, more than 50% of the ESTs correspond to genes of unknown function, reflecting the divergent evolutionary status of this parasite. A newly recognized class of genes was identified based on its similarity to sequences known only from other members of the same phylum, therefore identifying sequences that are apparently restricted to the Apicomplexa. Such genes may underlie pathways common to this group of medically important parasites, therefore identifying potential targets for intervention.
Footnotes
-
↵8 Corresponding author.
-
E-MAIL sibley{at}borcim.wustl.edu; FAX (314) 362-1232.
-
- Received August 21, 1997.
- Accepted November 18, 1997.
- Cold Spring Harbor Laboratory Press
