An activated Ick transgene promotes thymocyte development in rag-1 mutant mice

Abstract

Expression of the T cell receptor β (TCRβ) chain is necessary for the transition from the CD4-CD8- stage in the major up thymocyte lineage. The protein tyrosine kinase p56lck has been implicated in the regulation of early thymocyte differentiation and of allelic exclusion at the TCRβ locus. Using mice overexpressing an activated lck transgene and mice with a disruption of the lck gene, we demonstrate that p56 lck participates in a pathway that regulates the expansion of the pool of CD4+CD8+ thymocytes to wild-type levels. In addition, p56lck may be involved in the down-regulation of the putative pre-TCR on CD4+CD8+ thymocytes. © 1994.