Depletion of the RNA-binding protein PURA triggers changes in posttranscriptional gene regulation and loss of P-bodies

Abstract

The RNA-binding protein PURA is implicated in the rare, monogenetic, neurodevelopmental disorder PURA Syndrome. However, very little is known about the affected molecular pathways. PURA has been reported to bind DNA and RNA and to be connected to different cellular functions. Here, we show that PURA predominantly resides in the cytoplasm, where it binds to thousands of transcripts. Many of these transcripts change abundance in response to PURA depletion, in parts reflected in altered protein expression levels. A closer inspection of the regulated proteins indicates a role of PURA in immune responses, mitochondrial function, autophagy and processing (P)-body activity. Intriguingly, reduced PURA levels lower the expression of the integral P-body component LSM14A and strongly impair P-bodies in human cells. Furthermore, PURA knockdown results in stabilization of P-body-associated transcripts, whereas other mRNAs are decreased. Hence, reduced PURA levels, as reported in patients with PURA syndrome, are associated with the formation and composition of the phase-separated RNA processing machinery. Our study on the RNA-binding protein PURA provides a blueprint for the comprehensive understanding of the tight connection between P-body-associated RNA regulation and neurodevelopmental disorders.