Biology of tRNAs in Trypanosoma brucei during stress

Cristodero, Marina; Fricker, Roger; Schneider, André; Polacek, Norbert (5 September 2016). Biology of tRNAs in Trypanosoma brucei during stress (Unpublished). In: 26th tRNA Conference. Jeju, Korea. 04.-08.09.2016.

Official URL: https://trna2016.org/

Regulation of gene expression has to be tightly controlled. Especially under adverse growth conditions, e.g. stress, changes in expression patterns should occur rapidly for cells to survive. In recent years tRNA-derived fragments have emerged as regulators of gene expression during stress in a plethora of organisms and have been shown to affect gene expression at different levels. The pathogenic protozoan parasite Trypanosoma brucei largely lacks the ability to regulate transcription of protein coding genes and all genes are transcribed polycistronically. Therefore they heavily rely on posttranscriptional means to regulate gene expression. We are particularly interested in the changes that happen on tRNA molecules during stress and how these might affect gene expression and parasite survival. Our first stunning discovery was the shortening of the bulk of the tRNA population during nutritional stress. This shortening happens at the expense of the universally conserved 3’-CCA tail. We could show that the tRNA shortening can be partly reversed by overexpressing the CCA adding enzyme, but high levels of the enzyme are detrimental for cell growth. During nutritional stress the endogenous levels of the enzyme do not seem to change thus hinting at possible post-translational means to regulate the CCA-adding activity. In vitro experiments have shown that the shortened tRNAs can be repaired by the CCA-adding enzyme. Despite the strong decrease in polysomes triggered by stress the tRNAs lacking the complete CCA-tail are enriched in the polysome fraction, suggesting a function for these tRNA species in translation control. We are at the moment investigating two main aspects of the CCA-tail shortening: the regulation of the CCA-adding enzyme activity during stress and the identity of the possible nuclease involved in CCA-tail shortening.

Item Type:

Conference or Workshop Item (Poster)

Division/Institute:

08 Faculty of Science > Departement of Chemistry and Biochemistry

Graduate School:

Graduate School for Cellular and Biomedical Sciences (GCB)

UniBE Contributor:

Cristodero, Marina; Fricker, Roger; Schneider, André and Polacek, Norbert

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry

Language:

English

Submitter:

Christina Schüpbach

Date Deposited:

26 Jan 2017 09:54

Last Modified:

26 Jan 2017 09:54

URI:

https://boris.unibe.ch/id/eprint/92648

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