Posttranscriptional regulation of TNF mRNA: a paradigm of signal-dependent mRNA utilization and its relevance to pathology.

The relationship between TNF and immune pathology forced an intense research into the regulation of its biosynthesis that extends to multiple mechanisms controlling the utilization of its mRNA. These posttranscriptional mechanisms gradually and variably impose a series of flexible rate-limiting controls to modify the abundance of the TNF mRNA and the rate of its translation in response to environmental signals. Mechanistically, these controls consist of signaling networks converging to RNA-binding proteins and microRNAs, which in turn target a code of secondary or tertiary ribonucleotide structures located on the TNF mRNA. The outcome of these interactions is the stringent control of this mRNA's maturation, localization, turnover and translation. A wealth of molecular and genetic data highlighted that if these posttranscriptional interactions fail, they perturb cellular responses to provide the impetus for TNF-mediated inflammatory disease. Here, we highlight the parameters guiding the posttranscriptional regulation of TNF mRNA and their relevance to homeostasis and pathology.