Genome-wide Analysis Identifies Interleukin-10 mRNA as Target of Tristetraprolin

Abstract

Tristetraprolin (TTP) is an RNA-binding protein required for the rapid degradation of mRNAs containing AU-rich elements. Targets regulated by TTP include the mRNAs encoding tumor necrosis factor-␣, granulocyte-macrophage colony-stimulating factor, interleukin-2 (IL-2), and immediate early response 3. To identify novel target mRNAs of TTP in macrophages, we used a genome-wide approach that combines RNA immunoprecipitation and microarray analysis. A list was compiled of 137 mRNAs that are associated with TTP with an estimated accuracy on the order of 90%. Sequence analysis revealed a highly significant enrichment of AU-rich element motifs, with AUUUA pentamers present in 96% and UUAUUUAUU nonamers present in 44% of TTP-associated mRNAs. We further show that IL-10 is a novel target regulated by TTP. IL-10 mRNA levels were found to be elevated because of a reduced decay rate in primary macrophages from TTP ؊/؊ mice. Our study demonstrates the importance of experimental approaches for identifying targets of RNA-binding proteins.

MicroRNA-466l Upregulates IL-10 Expression in TLR-Triggered Macrophages by Antagonizing RNA-Binding Protein Tristetraprolin-Mediated IL-10 mRNA Degradation

“…It was shown recently that bone marrow-derived macrophages from TTP-deficient mice have longer IL-10 mRNA t 1/2 than the cells from wild-type mice, indicating that IL-10 can be regulated by TTP in a posttranscriptional manner (16). It is possible that miR-466l upregulates IL-10 expression by downregulating TTP.…”

“…TTP coordinately destabilizes these transcripts by recruiting the RNA decay machinery (15). TTP also can destabilize the anti-inflammatory cytokine IL-10 mRNA by binding to the ARE (16). It has been concluded that miRNAs mediate target mRNA degradation or translation repression modestly (17), whereas RBPs, such as TTP, can mediate rapid mRNA degradation (18,19).…”

dTIS11 Protein-dependent Polysomal Deadenylation Is the Key Step in AU-rich Element-mediated mRNA Decay in Drosophila Cells

“…TTP belongs to a family of evolutionary conserved zinc finger RNA-binding proteins able to bind AREs, thereby accelerating mRNA degradation. First identified as a regulator of TNF-␣ production (2), TTP has since been recognized to control the degradation of a large variety of ARE mRNAs including mediators of the inflammatory and the anti-inflammatory responses (3,4). The TIS11 protein family contains three members in humans and four members in mice.…”

Novel Highly Sensitive IL-10–β-Lactamase Reporter Mouse Reveals Cells of the Innate Immune System as a Substantial Source of IL-10 In Vivo

“…Previously, we also confirmed with two different reporter genes, luciferase and EGFP, that the 39 UTR of IL-10 negatively regulates the protein production (19). The rapid degradation of Il10 mRNA is mediated, for example, by binding of AU-rich element binding factor 1, tristetraprolin, or microRNA (hsamiR-106a) to the 39 UTR (40,43,44). Taken together, this intrinsic instability of Il10 mRNA results in low and transient expression of IL-10 protein and consequently restricts the sensitivity of a reporter gene like EGFP that is known to have a high limit of detection (∼10 5 molecules/cell) (7).…”