A novel, inducible and T cell-specific enhancer located at the 3' end of the T cell receptor alpha locus.

A novel, powerful and T-cell-specific enhancer element has been identified at 3 kb 3' of the mouse T cell receptor (TCR) C alpha (constant) gene. A previous report of an intragenic enhancer could not be confirmed. The unique organization of the TCR alpha locus and transcriptional data of the alpha promoter suggest that this enhancer can act over 69 kb. This feature of the alpha enhancer may lead to deregulation of c-myc and other oncogenes translocated to this locus in many T cell leukemias, resulting in T cell neoplasia. The enhancer was localized to 230 bp of DNA and has been found to be inducible in an immature T lymphoid cell line. Deletions localizing critical regions and T-cell-specific binding proteins of this enhancer are described.