ARE-mediated decay controls gene expression and cellular metabolism upon oxygen variations

Area of Science:

• Cellular Biology
• Molecular Biology
• Gene Regulation

Background:

• Hypoxia induces significant changes in cellular transcription.
• Reoxygenation leads to degradation of mRNAs produced during hypoxia.
• TIS11 proteins are key regulators of mRNA deadenylation and decay, particularly for transcripts with AU-rich elements (AREs).

Purpose of the Study:

• To investigate the role of TIS11 proteins in regulating gene expression during oxygen level fluctuations.
• To determine if AU-rich element (ARE)-containing transcripts are enriched during hypoxia and if their decay is TIS11-dependent.
• To understand the contribution of TIS11 to cellular recovery upon reoxygenation.

Main Methods:

• Bioinformatic analysis using the AREScore algorithm to identify ARE-containing transcripts in hypoxic Drosophila S2 cells.
• Experimental observation of dTIS11 levels in hypoxic and reoxygenated Drosophila S2 cells.
• Assessment of the role of dTIS11 in the down-regulation of ARE-containing transcripts and ImpL3 (Lactate Dehydrogenase) expression.

Main Results:

• Hypoxic Drosophila S2 cell transcriptome is enriched in ARE-containing transcripts, a trend conserved in human myeloid cells.
• dTIS11 levels decrease during hypoxia and return to normal upon reoxygenation.
• dTIS11 expression is required for the efficient down-regulation of ARE-containing transcripts, including ImpL3, during the hypoxia-normoxia transition.
• dTIS11 contributes to metabolic and proliferative recovery of cells upon reoxygenation.

Conclusions:

• AU-rich element-mediated decay (AMD) is crucial for controlling gene expression in response to oxygen concentration changes.
• dTIS11-mediated AMD plays a significant role in the rapid down-regulation of specific transcripts, such as ImpL3, upon reoxygenation.
• TIS11-dependent mRNA decay contributes to optimal cellular metabolic adaptation and recovery following hypoxic stress.