Human Pumilio proteins directly bind the CCR4-NOT deadenylase complex to regulate the transcriptome

Area of Science:

• Molecular Biology
• Genetics
• Developmental Biology

Background:

• Pumilio paralogs PUM1 and PUM2 are crucial RNA-binding proteins for vertebrate development and neurological functions.
• PUM1&2 regulate gene expression by promoting the degradation of target messenger RNAs (mRNAs).

Purpose of the Study:

• To elucidate the repression mechanism of human PUM1&2.
• To determine the impact of PUM1&2 on the transcriptome.
• To identify the molecular players involved in PUM1&2-mediated gene silencing.

Main Methods:

• Interaction studies to identify protein partners of PUM1&2.
• Isoform-level RNA sequencing to analyze transcriptome-wide effects.
• Functional domain dissection of PUM1&2 proteins.

Main Results:

• Subunits of the CCR4-NOT (CNOT) deadenylase complex are essential for PUM1&2 interaction and repression.
• PUM1&2 directly recruit CNOT complex to target mRNAs, leading to their degradation.
• A conserved N-terminal region of PUM1&2 mediates interaction with CNOT and confers repressive activity.
• The mRNA decapping enzyme DCP2 plays a role in PUM1&2-mediated repression.

Conclusions:

• Human PUM1&2 repress gene expression by directly recruiting the CNOT deadenylation complex.
• This recruitment initiates a decapping-dependent mRNA decay pathway.
• The findings provide a molecular model for PUM1&2 function in gene regulation.