The composition of untranslated regions in Trypanosoma cruzi genes

We collected the UTRs from Trypanosomacruzi genes that have been experimentally mapped and are publicly available, and made a comprehensive analysis of their composition features including sequence length, G+C content and relationship to ORF, composition of the most frequent words, and distribution of Simple Sequence Repeats (SSR). T. cruzi UTRs exhibit range length of 10–400 bp for 5′ UTR and 17–2800 for 3′ UTR. Both UTRs display mean G+C content of 40%. Ratios between the UTR and protein coding segments show that the 5′ UTR is limited to a maximum of 20% of the total length in the final transcript. The 5′ UTR most frequent words in the range 4–12 bases are almost exact complement to the 3′ UTR respective words. SSR in 3′ UTR are longer than in 5′ UTR and are mostly derived from TA/AT, TG/GT, and TTA/ATT. SSR accounts up to 20% of the nucleotide composition in 5′ UTR and up to 90% in the 3′ UTR.