NIH Research Festival
The Ccr4-Not complex regulates mRNA poly(A)-tail length to influence mRNA stability and/or translation in eukaryotic cells. The complex is formed by NOT and deadenylase modules. Several subunits of the complex have been implicated in various development phenotypes and diseases, alluding to its role in post-transcriptional gene regulation and cell fate decisions. We have previously shown that Ccr4-Not is required for mouse Embryonic Stem Cell (ESC) maintenance. To systematically dissect the function of the complex, we generated conditional deletion ESC lines for subunits in the NOT and deadenylase modules using CRISPR/Cas9 mediated genome editing. We found that individual deletion of the NOT module subunits, or simultaneous deletion of the deadenylases led to ESC differentiation. Mechanistically, NOT subunit deletions resulted in decreased complex stability, while deadenylase deletions led to compromised enzymatic activity. We determined the poly(A)-tail length, half-life, and steady-state abundance of mRNAs in wild-type and Ccr4-Not deletion ESCs. Consistent with the cellular phenotypes, the deletion of subunits that are essential for ESC maintenance increases poly(A)-tail length, half-life, and steady-state level in many mRNAs, especially those from genes involved in development and differentiation. Thus, we propose that Ccr4-Not maintains the ESC fate and prevents pre-mature differentiation by repressing differentiation gene expression via mRNA deadenylation. Further, we speculate that Ccr4-Not-mediated poly(A)-tail length regulation may act as a general post-transcriptional switch during cell fate transitions in development and disease. We will test the hypothesis by further analyzing our genomic datasets and examining the function of Ccr4-Not in other stem cell types and biological contexts.
Scientific Focus Area: Stem Cell Biology
This page was last updated on Monday, September 25, 2023