Zinc finger protein Zfp335 controls thymocyte differentiation and survival through b-selection-dependent and -independent mechanisms

T cell development proceeds in a series of developmental stages, which is precisely orchestrated by multiple signaling and molecular networks. Here we found a zinc finger protein Zfp335 intrinsically controls DN to DP transition, as T cell-specific deficiency in Zfp335 leads to a substantial accumulation of DN3 along with reduction of DP, CD4+ and CD8+ thymocytes. This developmental blockade at DN stage results from the impaired intracellular TCRß expression as well as increased susceptibility to apoptosis in thymocytes. Transcriptomic and ChIP-seq analyses revealed a direct regulation of transcription factors Bcl6 and Rorc by Zfp335. Importantly, enhanced expression of TCRß and Bcl6/Ror?T restores the developmental defect during DN3 to DN4 transition and improves thymocytes survival, respectively. These findings identify a critical role of Zfp335 in controlling T cell development by maintaining intracellular TCR? expression-mediated ß-selection and independently activating cell survival signaling. Overall design: Examination of DN4 thymocytes from the thymus of WT and Zfp335 deficient mice