Abstract
In this study, we describe a chemically induced mouse mutation that caused a complete and cell-intrinsic T cell deficiency. Development of other lymphoid lineages was also partially impaired and was severely compromised under competitive conditions. Positional cloning, retroviral transduction, and a somatic reversion event revealed that the causative mutation lay within Zbtb1 (zinc finger and BTB domain containing 1), a gene conserved throughout vertebrate evolution. Our data establish ZBTB1 as a critical determinant of T cell development and lymphopoiesis in general, most likely by acting as a transcriptional regulator.