CNOT3 supports ILC2 differentiation and function by destabilizing Tbx21 and Rorc transcripts

Area of Science:

• Immunology
• Molecular Biology
• Cell Biology

Background:

• Innate lymphoid cells (ILCs) are critical immune cells with distinct subtypes (ILC1, ILC2, ILC3) defined by transcription factors.
• Posttranscriptional regulation, particularly mRNA decay mediated by the CCR4-NOT complex, is vital for ILC function but remains poorly understood.
• CNOT3 is an essential subunit of the CCR4-NOT complex involved in mRNA deadenylation.

Purpose of the Study:

• To investigate the impact of mRNA decay on ILC differentiation and function.
• To determine the role of CNOT3 in the regulation of ILC2 cells.
• To elucidate the molecular mechanisms by which CNOT3 controls ILC2 transcriptional programs.

Main Methods:

• Conditional deletion of the Cnot3 gene in ILC2 cells.
• Analysis of gene expression, including transcription factors (T-bet, GATA-3, RORγt) and signature genes.
• Investigation of molecular interactions between CNOT3, Roquin, ZFP36L1, and target mRNAs (Tbx21, Rorc).
• Assessment of ILC2 function in models of airway allergy and helminth infection.

Main Results:

• Loss of CNOT3 in ILC2 cells resulted in aberrant expression of T-bet and RORγt.
• CNOT3 deficiency led to the upregulation of type 1 and type 3 signature genes in ILC2s.
• CNOT3 directly targeted Tbx21 and Rorc mRNAs via Roquin and ZFP36L1, respectively.
• Elevated T-bet suppressed GATA-3, impairing type 2 immune responses in vivo.
• CNOT3 deficiency compromised ILC2 function in airway allergy and helminth infection models.

Conclusions:

• CNOT3 is essential for maintaining ILC2 cell identity and function.
• CNOT3 restricts the expression of type 1 (T-bet) and type 3 (RORγt) transcriptional programs in ILC2s.
• This study reveals a critical role for mRNA decay in regulating ILC subset balance and immune homeostasis.