Toxoplasma gondii expressed sequence tags: insight into tachyzoite gene expression.

Analysis of DNA sequences from the 5' end of 239 directionally cloned Toxoplasma gondii RH strain tachyzoite-derived cDNAs revealed significant similarity to several classes of genes/proteins including 24 ribosomal proteins, five metabolic enzymes, four cell-cycle regulators and 15 previously cloned T. gondii genes. The remaining sequences with no significant match include several which were recovered more than once. The variety and redundancy of expressed sequence tags (ESTs GenBank accession numbers T62239-T62475) in this sample suggest that the tachyzoite cDNA library reflects tachyzoite gene expression. A large scale EST effort should uncover many new genes and provide a wealth of information about genes involved with the growth and proliferation of tachyzoites.