TRYPANOSOMA CRUZI HIGH MOBILITY GROUP B PROTEIN (TCHMGB) CAN ALTER CHROMATIN STRUCTURE AND AFFECTS IMPORTANT PARASITE FUNCTIONS

GONÇALVES CS; SERRA EC; TAVERNELLI LE; ALONSO VL; MOTTA CM; CRIBB P

Caxambu

Congreso; XXIII Annual Meeting of the Brazilian Society of Protozoology; 2017

Sociedade Brasileira de Protozoologia

HIGH MOBILITY GROUP Bs are abundant non-histone chromatin proteins. The DNA-HMGB interaction produces changes in chromatin structure thus affecting important nuclear processes like transcription, replication, recombination, DNA repair and chromosome segregation. TcHMGB, the HMGB from Trypanosoma cruzi, has two "HMG box" DNA binding domains and a unique N-terminal sequence that bears a nuclear localization signal (NLS) and a "DEK-C terminal? domain. We previously demonstrated that TcHMGB is expressed in the nucleus in all the parasite life stages and has architectural properties on DNA structure like its mammalian orthologs. Given the TcHMGB "architectural" properties, the particular characteristics of transcription in trypanosomatids and evidence gathered about epigenetic mechanisms controlling gene expression, we decided to evaluate the role of TcHMGB in vivo. With the aim of investigating TcHMGB functions, we constructed transgenic parasites capable of overexpressing the protein under tetracycline induction. We showed that TcHMGB can interact with chromatin DNA in vivo, altering where an overexpression of the protein altered the chromatin state in epimastigotes making it more sensible to micrococcal nuclease treatment. Overexpression of TcHMGB caused a dramatic decrease in epimastigotes growth and an arrest in G2/M phase. Also, other stages´ functions resulted impaired: we observed a decrease in trypomastigote in vitro infectivity on Vero cells, amastigotes proliferation and trypomastigotes release from infected cells in vitro in overexpressing parasites. These results suggest that trypanosomatid HMGB proteins can be considered pleiotropic players involved in trypanosomes key cellular processes, and they should also be considered as putative actors in Chagas disease pathogenesis.