The CCR4-CAF1-NOT complex is a major cytoplasmic deadenylation complex in yeast and mammals. This complex associates with RNA-binding proteins and microRNAs to repress translation of target mRNAs. We sought to determine how CCR4 and CAF1 participate in repression and control of maternal mRNAs using Xenopus laevis oocytes. We show that Xenopus CCR4 and CAF1 enzymes are active deadenylases and repress translation of an adenylated mRNA. CAF1 also represses translation independent of deadenylation. The deadenylation-independent repression requires a 5 cap structure on the mRNA; however, deadenylation does not. We suggest that mere recruitment of CAF1 is sufficient for repression, independent of deadenylation.

Regulatory complexes formed on mRNAs control translation, stability, and localization. These complexes possess two activities: one that binds RNA and another-the effector-that elicits a biological function. The Pumilio and FBF (PUF) protein family of RNA binding proteins provides a versatile scaffold to design and select proteins with new specificities. Here, the PUF scaffold is used to target translational activation and repression of specific mRNAs, and to induce specific poly(A) addition and removal. To do so, we linked PUF scaffold proteins to a translational activator, GLD2, or a translational repressor, CAF1. The chimeric proteins activate or repress the targeted mRNAs in Xenopus oocytes, and elicit poly(A) addition or removal. The magnitude of translational control relates directly to the affinity of the RNA-protein complex over a 100-fold range of K d . The chimeric proteins act on both reporter and endogenous mRNAs: an mRNA that normally is deadenylated during oocyte maturation instead receives poly(A) in the presence of an appropriate chimera. The PUF-effector strategy enables the design of proteins that affect translation and stability of specific mRNAs in vivo.CAF1/RNA stability | GLD2/polyadenylation

The presence of DNA in the cytosol is usually a sign of microbial infections, which alerts the host innate immune system to mount a defense response. Cyclic GMP‐AMP synthase (cGAS) is a critical cytosolic DNA sensor that elicits robust innate immune responses through the production of the second messenger, cyclic GMP‐AMP (cGAMP), which binds and activates stimulator of interferon genes (STING). However, cGAS binds to DNA irrespective of DNA sequence, therefore, self‐DNA leaked from the nucleus or mitochondria can also serve as a cGAS ligand to activate this pathway and trigger extensive inflammatory responses. Dysregulation of the cGAS‐STING pathway is responsible for a broad array of inflammatory and autoimmune diseases. Recently, evidence has shown that self‐DNA release and cGAS‐STING pathway over‐activation can drive lung disease, making this pathway a promising therapeutic target for inflammatory lung disease. Here, we review recent advances on the cGAS‐STING pathway governing self‐DNA sensing, highlighting its role in pulmonary disease.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected more than 180 million people since the onset of the pandemic. Despite similar viral load and infectivity rates between children and adults, children rarely develop severe illness. Differences in the host response to the virus at the primary infection site are among the mechanisms proposed to account for this disparity. Our objective was to investigate the host response to SARS-CoV-2 in the nasal mucosa in children and adults and compare it with the host response to respiratory syncytial virus (RSV) and influenza virus. We analyzed clinical outcomes and gene expression in the nasal mucosa of 36 children with SARS-CoV-2, 24 children with RSV, 9 children with influenza virus, 16 adults with SARS-CoV-2, and 7 healthy pediatric and 13 healthy adult controls. In both children and adults, infection with SARS-CoV-2 led to an IFN response in the nasal mucosa. The magnitude of the IFN response correlated with the abundance of viral reads, not the severity of illness, and was comparable between children and adults infected with SARS-CoV-2 and children with severe RSV infection. Expression of ACE2 and TMPRSS2 did not correlate with age or presence of viral infection. SARS-CoV-2–infected adults had increased expression of genes involved in neutrophil activation and T-cell receptor signaling pathways compared with SARS-CoV-2–infected children, despite similar severity of illness and viral reads. Age-related differences in the immune response to SARS-CoV-2 may place adults at increased risk of developing severe illness.