Functional profiling of the Tritrichomonas foetus transcriptome and proteome

Tritrichomonas foetus is a potent veterinary pathogen, causing bovine and feline trichomoniasis. The principal clinical manifestation of infection in cattle is inflammation of the genital tract and infertility. In feline, the parasite causes large-bowel disease resulting in chronic diarrhea. In contrast to other well-studied protozoan, genetic data regarding the molecular characterization and expression in T. foetus is far less understood. In this study, the first large-scale T. foetus expressed sequence tag (TfEST) project was conducted on 5064 randomly selected EST clones from a non-normalized unidirectional Tf30924 cDNA library. Assembling of 5064 single-pass sequences from the 5′ end resulted in 713 contigs and 1961 singlets. BLAST search revealed that 53.52% of the unigenes showed significant similarity to known sequences or protein motifs/domains. Functional classifications indicated that most of the unigenes are involved in translation, ribosomal structure and ribosome biogenesis. The average GC content of the T. foetus transcriptome is 40.93%. Intriguingly, only 31.29% of the unigenes contain the classical AAUAAA polyadenylation signal sequence at the 3′-UTR region. Furthermore, a panel of potential chemotherapeutic targets was also identified for the first time in T. foetus. The protein expression levels were verified by using two-dimensional electrophoresis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. A total of 68 highly abundant protein spots were successfully identified in the reference 2-DE map based on our T. foetus-specific protein database. The EST dataset and the reference 2-DE map established in the present study will provide a foundation for future whole genome sequencing project and comparative transcriptomic/proteomic analyses to provide potential drug targets against T. foetus infection.