Proteolysis autoregulates expression of the cyanobacterial DEAD-box RNA helicase CrhR, in response to change in growth temperature

• Author / Creator

  Tarassova, Oxana S.

• The DEAD box cyanobacterial RNA helicase redox, CrhR, in Synechocystis sp. PCC 6803 is induced in response to environmental stress conditions causing reduction of the redox status of the photosynthetic electron transport chain, with temperature being one of the major conditions commonly encountered in the environment. A basal level of CrhR protein abundance is observed at 30oC, which is significantly increased at 20oC. In this study CrhR protein abundance was found to be regulated by a temperature-controlled proteolytic mechanism that is most active in the first few hours of growth at 30oC. CrhR proteolytic degradation was shown to be autoregulated as crhRTR mutant exhibits elevated levels of non-functional truncated CrhRTR protein regardless of growth temperature. Based on the results a model for CrhR post-translational regulation at 30oC by autoregulated proteolytic degradation was proposed. CrhR represents the second example of proteolytically autoregulated protein, being the first known example among RNA helicases.

• Subjects / Keywords

  • Synechocystis
  • DEAD-box
  • CrhR

• Graduation date

  Fall 2013

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3B27Q278

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.