Evaluation of cDNA libraries of the euglenoid Euglena gracilis.

DOS SANTOS FERREIRA V., ROCCHETTA I., LABOVSKY V., RUIZ L., CONFORTI V., LEVIN M.J.

Buenos Aires

Congreso; 1º Congreso Latinoamericano sobre Biotecnología Algal.; 2004

Universidad de Buenos Aires

Directional cDNA libraries were constructed from mRNA of the commercial strain E. gracilis UTEX 753 (U). One thousand Expression Sequence Tags (EST’s) of an average size of 500bp. were generated. To identify correspondent cDNA into all open reading frames and compared them with the nonredundant protein database using BLASTX. We came upon with a 12% of similarities with ESTs and 47% with unknown identity. We found out that 612 ESTs showed similarity to known proteins and that 388 showed no similarity. From the 612 genes with know similarity, 111 showed similarity to poorly classified ESTs, within them A. thaliana represented more than the 40%. From the total ESTs, 910 were non redundant and only 90 were redundant sequences. Microarrays were constructed for the study of gene expression changes in E. gracilis grown in the presence of different stress environmental conditions. Four hybridization conditions with RNAs labelled with Cy5/Cy3 were assayed: I) U/wild type strain (MAT), ii)U/MAT grown with streptomycin supplementation, iii) U/MAT grown in the dark, and iv) U/MAT grown in the presence of chromium. We focus our results within two groups (coming from the BLAST’s results) Plantae (including unicellular algae) and Kinetoplastida. Using Array Vision software (Imaging Research Inc.) we found out 60 and 30 spots of known identity within those groups respectively showing changes in their expressions ratio after each of the stress conditions. The sequencing and expression data obtained on this work are the first molecular data generated from nuclear genome of E. gracilis and the starting point for future comparative studies among Euglenozoa.