Stress Induces Changes in the Phosphorylation of Trypanosoma cruzi RNA Polymerase II, Affecting Its Association with Chromatin and RNA Processing

Autor(es)

Rocha, Antonio Augusto ^[1] ; Moretti, Nilmar Silvio ^[1] ; Schenkman, Sergio ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Paulo, Dept Microbiol Imunol & Parasitol, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Eukaryotic Cell; v. 13, n. 7, p. 855-865, JUL 2014.
• Citações Web of Science: 2

Resumo

The phosphorylation of the carboxy-terminal heptapeptide repeats of the largest subunit of RNA polymerase II (Pol II) controls several transcription-related events in eukaryotes. Trypanosomatids lack these typical repeats and display an unusual transcription control. RNA Pol II associates with the transcription site of the spliced leader (SL) RNA, which is used in the trans-splicing of all mRNAs transcribed on long polycistronic units. We found that Trypanosoma cruzi RNA Pol II associated with chromatin is highly phosphorylated. When transcription is inhibited by actinomycin D, the enzyme runs off from SL genes, remaining hyperphosphorylated and associated with polycistronic transcription units. Upon heat shock, the enzyme is dephosphorylated and remains associated with the chromatin. Transcription is partially inhibited with the accumulation of housekeeping precursor mRNAs, except for heat shock genes. DNA damage caused dephosphorylation and transcription arrest, with RNA Pol II dissociating from chromatin although staying at the SL. In the presence of calyculin A, the hyperphosphorylated form detached from chromatin, including the SL loci. These results indicate that in trypanosomes, the unusual RNA Pol II is phosphorylated during the transcription of SL and polycistronic operons. Different types of stresses modify its phosphorylation state, affecting pre-RNA processing. (AU)

• Processo FAPESP: 12/09403-8 - Estudo do papel das modificações de cromatina nos mecanismos de reparo de dano no DNA e controle da transcrição em Trypanosoma
• Beneficiário: Nilmar Silvio Moretti
• Linha de fomento: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 11/51973-3 - Mecanismo de sinalização celular de Trypanosoma em resposta a alterações nutricionais e agentes genotóxicos
• Beneficiário: Sergio Schenkman
• Linha de fomento: Auxílio à Pesquisa - Temático
• Processo FAPESP: 12/09327-0 - Caracterização e função da proteína eiF5A de Trypanosoma
• Beneficiário: Antonio Augusto Rocha
• Linha de fomento: Bolsas no Brasil - Pós-Doutorado