Figure 2.

Alternative roles of NEAT1 and paraspeckles: Impact on circadian gene expression and mitochondrial cross-talk

NEAT1, among other components of the paraspeckle, follows a circadian expression pattern. This leads to rhythmic retention of certain mRNAs in the paraspeckle, including some core-clock mRNAs, allowing control of their circadian expression. On the other hand, NEAT1 regulates mitochondrial homeostasis and protects cells from apoptosis through the paraspeckle-mediated function. Mitochondrial stress favors NEAT1 expression by activation of the transcription factor ATF2, which binds to its promoter. NEAT1 upregulation correlates with an increase in the number of paraspeckles and adoption of an elongated morphology, together with enhanced retention of mRNAs. Among them, mRNAs of nucleus-encoded mitochondrial proteins (mito-mRNAs) conform an enriched group, and repression of their translation avoids induction of the mitochondrial pathway of apoptosis. This figure was created with BioRender.