Recruitment of mRNAs to cytoplasmic ribonucleoprotein granules in trypanosomes.
Trypanosomes are outstanding examples of the importance of mRNA metabolism in the regulation of gene expression, as these unicellular eukaryotes mostly control protein synthesis by post-transcriptional mechanisms. Here, we show that mRNA metabolism in these organisms involves recruitment of mRNAs and proteins to microscopically visible ribonucleoprotein granules in the cytoplasm. These structures engage transcripts that are being translated and protect mRNAs from degradation. Analysis of the protein composition of trypanosomal mRNA granules indicated that they contain orthologous proteins to those present in P bodies and stress granules from metazoan organisms. Formation of mRNA granules was observed after carbon-source deprivation of parasites in axenic culture. More important, mRNA granules are formed naturally in trypanosomes present in the intestinal tract of the insect vector. We suggest that trypanosomes make use of mRNA granules for transient transcript protection as a strategy to cope with periods of starvation that they have to face during their complex life cycles.
Cassola
Alejandro
A
Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico Chascomús, UNSAM-CONICET, 1650 San Martín, Provincia de Buenos Aires, Argentina.
De Gaudenzi
Javier G
JG
Frasch
Alberto C
AC
D020816:Amino Acid Motifs; D000818:Animals; D002244:Carbon / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D003594:Cytoplasmic Granules / Q000187:drug effects / Q000378:metabolism*; D005508:Food Deprivation; D041981:Gastrointestinal Tract / Q000187:drug effects; D007303:Insect Vectors / Q000187:drug effects / Q000469:parasitology; D008954:Models, Biological; D010271:Parasites / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D015800:Protozoan Proteins / Q000378:metabolism; D011691:Puromycin / Q000494:pharmacology; D034443:RNA Transport / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D012261:Ribonucleoproteins / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects; D014346:Trypanosoma brucei brucei / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D014349:Trypanosoma cruzi / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*
D015800:Protozoan Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; C500732:UBP1 protein, Trypanosoma cruzi; D011691:Puromycin; D002244:Carbon; D003513:Cycloheximide