Event Title

Translation Dependence of siRNA precursors in T. thermophila

Research Mentor(s)

Suzanne Lee

Description

Many organisms possess “junk” DNA that, in some cases, may be harmful if expressed, requiring cellular pathways to prevent such expression. Tetrahymena thermophila is one such organism and it appears to employ an RNA interference (RNAi) pathway to limit the expression of repetitive or unusually structured non-protein coding regions of the genome through small interfering RNA (siRNA) production. However, whether siRNA precursors generated from these DNA regions are also degraded by translation-dependent RNA quality control pathways has been unclear. We have found that treatment of Tetrahymena thermophila with the translational inhibitor cycloheximide (CHX) causes an accumulation of a subset of siRNA producing transcripts while also reducing or leaving unchanged the levels of others. This suggests that at least some of the siRNA precursors may be subject to translation-dependent degradation (TDD), though other possible explanations remain to be ruled out. Our current efforts are focused on investigating possible mechanisms behind the response of siRNA precursors to CHX. We are examining two hypotheses: for one, translation dependent decay (TDD) may be acting on siRNA precursors in parallel with or in competition with RNAi. Alternatively, CHX may interact with a transcriptional inhibitor. In this model, the action of CHX blocks the inhibitor, upregulating transcription. We also plan on examining the effects of CHX on other siRNA precursors.

Document Type

Event

Start Date

17-5-2018 9:00 AM

End Date

17-5-2018 12:00 PM

Department

Biology

Comments

Outstanding Poster Award Recipient

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this documentation for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

Language

English

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May 17th, 9:00 AM May 17th, 12:00 PM

Translation Dependence of siRNA precursors in T. thermophila

Many organisms possess “junk” DNA that, in some cases, may be harmful if expressed, requiring cellular pathways to prevent such expression. Tetrahymena thermophila is one such organism and it appears to employ an RNA interference (RNAi) pathway to limit the expression of repetitive or unusually structured non-protein coding regions of the genome through small interfering RNA (siRNA) production. However, whether siRNA precursors generated from these DNA regions are also degraded by translation-dependent RNA quality control pathways has been unclear. We have found that treatment of Tetrahymena thermophila with the translational inhibitor cycloheximide (CHX) causes an accumulation of a subset of siRNA producing transcripts while also reducing or leaving unchanged the levels of others. This suggests that at least some of the siRNA precursors may be subject to translation-dependent degradation (TDD), though other possible explanations remain to be ruled out. Our current efforts are focused on investigating possible mechanisms behind the response of siRNA precursors to CHX. We are examining two hypotheses: for one, translation dependent decay (TDD) may be acting on siRNA precursors in parallel with or in competition with RNAi. Alternatively, CHX may interact with a transcriptional inhibitor. In this model, the action of CHX blocks the inhibitor, upregulating transcription. We also plan on examining the effects of CHX on other siRNA precursors.