The ETS family transcription factors Etv5 and PU.1 function in parallel to promote Th9 cell development

The IL-9-secreting Th9 subset of CD4 T helper cells develop in response to an environment containing IL-4 and TGFβ, promoting allergic disease, autoimmunity, and resistance to pathogens. We previously identified a requirement for the ETS family transcription factor PU.1 in Th9 development. In this report we demonstrate that the ETS transcription factor ETV5 promotes IL-9 production in Th9 cells by binding and recruiting histone acetyltransferases to the Il9 locus at sites distinct from PU.1. In cells that are deficient in both PU.1 and ETV5 there is lower IL-9 production than in cells lacking either factor alone. In vivo loss of PU.1 and ETV5 in T cells results in distinct affects on allergic inflammation in the lung, suggesting that these factors function in parallel. Together, these data define a role for ETV5 in Th9 development and extend the paradigm of related transcription factors having complementary functions during differentiation