Serial analysis of gene expression (SAGE) in bovine trypanotolerance: preliminary results

Abstract

-In Africa, trypanosomosis is a tsetse-transmitted disease which represents the most important constraint to livestock production. Several indigenous West African taurine (Bos taurus) breeds, such as the Longhorn (N'Dama) cattle are well known to control trypanosome infections. This genetic ability named "trypanotolerance" results from various biological mechanisms under multigenic control. The methodologies used so far have not succeeded in identifying the complete pool of genes involved in trypanotolerance. New post genomic biotechnologies such as transcriptome analyses are efficient in characterising the pool of genes involved in the expression of specific biological functions. We used the serial analysis of gene expression (SAGE) technique to construct, from Peripheral Blood Mononuclear Cells of an N'Dama cow, 2 total mRNA transcript libraries, at day 0 of a Trypanosoma congolense experimental infection and at day 10 post-infection, corresponding to the peak of parasitaemia. Bioinformatic comparisons in the bovine genomic databases allowed the identification of 187 up-and downregulated genes, EST and unknown functional genes. Identification of the genes involved in trypanotolerance will allow to set up specific microarray sets for further metabolic and pharmacological studies and to design field marker-assisted selection by introgression programmes. SAGE / trypanotolerance / N'Dama / Trypanosoma congolense / transcriptomics

Bovine Transcriptome Analysis by SAGE Technology during an Experimental Trypanosoma congolense Infection

“…T5000‐01) and were used in a differential comparison of expressed genes before and after T. congolense infection. The confrontation of the sequenced tags observed with the potential tags in the international databanks (Unigen, Tigr, SageMap) allowed us to identify the tags obtained and to confirm our previous results 29 …”

“…Four libraries were developed with a trypanotolerant N'Dama cattle: the first one before the experimental infection (ND0), a second corresponding to the maximum parasitemia (NDm), a third at minimum packed cell volume or maximum anemia (NDa), and a final library after the recovery of the initial value for packed cell volume (PCV) and no parasite in serum (NDf). The comparison of all the libraries at different stages before and during infection will allow us to refine the results already found in our previous study 29 …”

“…The SAGE method generates 14‐bp tags derived from the 3' end of each transcript present in a cell or tissue type at a particular time. These tags can be rapidly analyzed and matched to genomic sequence data and permit identification of specific genes and their relative frequencies 29–31,37–39 . The mRNA are isolated from the whole RNA population using oligo‐dT beads that retain the mRNA by their poly A + tail.…”

“…Today, in addition to the microarrays, a biotechnology much more significant than the EST approaches allows access to an exhaustive functional analysis 28 . The serial analysis of gene expression (SAGE) is based on a “transcriptomic” strategy able to characterize the differential expression of whole expressed genes 29–31 …”

Evolving anti-disease strategies from biochemical pathogenesis of african trypanosomiasis

“…19 Tumour necrosis factor gene was reported to play a role in resistance to trypanosome infection in mice. 20 Higher serum amyloid A expression levels may support trypanotolerance in cattle.…”