A NEW HOMEOBOX GENE CONTRIBUTES THE DNA-BINDING DOMAIN OF THE T(1-19) TRANSLOCATION PROTEIN IN PRE-B ALL

It was previously shown that the chromosome 19 breakpoint of the t(1;19)(g23;p13.3) translocation, found in human pre-B cell acute lymphoblastic leukemias, is within the E2A transcription factor gene on chromosome 19. A cell line with this translocation contains two novel chimeric mRNAs, both with the same 5′ E2A sequences but with different lengths of 3′ sequence from a previously unrecognized gene dubbed prl, located on chromosome 1. The chimeric RNAs encode a protein that lacks 171 amino acids of E2A, including its DNA binding and dimerization motifs, but have instead a homeobox-related sequence from prl. Therefore, the production of a chimeric E2A-Prl protein may contribute to the acute lymphoblastic phenotype by directly altering the expression of genes normally responsive to the Prl homeoprotein. © 1990.