CONICET | Buscador de Institutos y Recursos Humanos

Trypanosoma cruzi BDF2, a protein that senses histone acetylation and could participate in chromatin dynamics. Gabriela Vanina Villanovaa*, Sheila Cristina Nardelli b, Maria Cristina M. Motta c, Sergio Schenkman b, Esteban Serra a. a Instituto de Biología Molecular y Celular de Rosario, Facultad de Ciencias Bioquímicas y Farmacéuticas, Suipacha 351, 2000, Rosario, Argentina.b Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, R. Botucatu 862 8a, 04023-062 São Paulo, Brazil.c Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21949-900 R.J., Brazil. villanova@ibr.gov.ar Histone tail post-translational modifications regulate many cellular processes. Among these modifications, phosphorylation, methylation and acetylation have already been described in trypanosomatid histones. Bromodomains, together with chromodomains and histone-binding SANT domains, were proposed to be responsible for the histone code reading. The Trypanosoma cruzi genome encodes four coding sequences (CDSs) that contain a bromodomain, named TcBDF1-4. We have shown that one of those, TcBDF2, is expressed in discrete regions inside the nucleus of all the parasite life cycle stages, between dense and less dense chromatin regions. TcBDF2 binds H4 (with preference for K10 and K14 acetylated residues) and H2A purified histones from T. cruzi. Also, this protein was accumulated after UV irradiation of epimastigotes. These results suggest that TcBDF2 could be implicated in chromatin remodelling as part of a larger protein complex as other known bromodomain proteins. This kind of complexes has a broad range of functions participating in genome expression, maintenance and duplication in other organisms, A partial TcBDF2 colocalization with RNA polymerase II was observed in immunolocalization experiments. In order to analyze TcBDF2 function we attempted expression of a dominant negative TcBDF2. TcBDF2 fused to c-myc tag and C-terminal deleted TcBDF2 (TcBDF2DC) transgenes were expressed from a tetracycline regulated promoter using pTcINDEX-I vector. An important reduction in growth rate was observed in parasites expressing TcBDF2DC as well as cells having abnormal combinations of kineto-nucleo. In addition, these parasites presented diminished resistance to UV irradiation compared to wild type. Although more results are needed to understand the role of TcBDF2 in trypanosomes biology, TcBDF2 accumulation after UV irradiation and its ability to interact with acetylated histones support the hypothesis that it could have a role in chromatin dynamics as a member of a chromatin remodelling complex. Supported by ANPCyT, CONICET, CNPq and FAPESP.