Fusion of the Leucine Zipper Gene <i>HLF</i> to the <i>E2A</i> Gene in Human Acute B-Lineage Leukemia

Abstract

A t(17;19) chromosomal translocation in early B-lineage acute leukemia was shown to result in chimeric transcripts that contain sequences from the E2A basic helix-loop-helix transcription factor gene on chromosome 19, fused to sequences from a previously unidentified gene (HLF) on chromosome 17 that encodes a hepatic leukemia factor. The chimeric protein consisted of the amino-terminal transactivation domain of E2A linked to the carboxyl-terminal basic region-leucine zipper domain of HLF. HLF was normally expressed in liver and kidney, but not in lymphoid cells, and was found to be closely related to the leucine zipper-containing transcription factors DBP (albumin D-box binding protein) and TEF (thyrotroph embryonic factor), which regulate developmental stage-specific gene expression.