Elongator family of histone acetyltransferases in Trypanosoma cruzi

MEYER CG; TORRES HN; FLAWIÁ MM; ALONSO GD

Rosario. Santa Fe, Argentina.

Congreso; VIII Congreso Argentino de Protozoologia y Enfermedades Parasitarias.; 2008

In most eukaryotic cells, histone tails are subjected to post-translational modifications such as acetylation, methylation, phosphorylation, ADP-ribosylation and ubiquitination. Combined modifications may constitute a code that regulates chromatin structure, replication, DNA damage repair, transcription and genomic imprinting. Two types of histone acetyltransferases (HATs) are present in Tritryps genome. The MYST family of HATs was recently described in T. brucei and has been previously reported by our lab in T. cruzi. In this work we focus on the other type of HATs known as Elongator. We PCR-amplified a sequence with Elp3 identity named TcElp3 and subcloned it for expression in E. coli. Purified recombinant protein showed no HAT activity in vitro probably because HAT proteins form multiprotein complexes in vivo. We also cloned TcElp3 into yeast expression vectors in order to complement an Elp3 deficient yeast strain but wild type phenotype could not be restored in transformed cells. TcElp3 specific antibodies were generated in mice and used to analyze subcellular localization by Western blot and immunofluorescence. We subsequently studied the effect of histone deacetylases inhibitors trichostatin A (TSA) and sodium butyrate in epimastigotes grown in vitro. Strong proliferation inhibition was observed when parasites were treated with 50 nM TSA. Interestingly a sub G1 peak and cell cycle alterations were observed in flow cytometry DNA histogram. Over-expression of TcElp3 in CL Brener and Tulahuen 2 strain epimastigotes showed no apparent morphological or growth deficiencies. These results contribute to the challenging task of unraveling histone post-translational modifications function in trypanosomatids.