In a previous paper (Proc. Natl. Acad. Sci. USA 84, 4264, 1987) we reported that a DNA fragment containing a gene for the T-cell receptor beta chain, which had been excised from chromosome 7q35 during D beta-J beta joining, was inserted into chromosome 6p21.3 in a patient with acute T-cell leukemia. We have since screened for genes in the vicinity of the insertion point and have identified a gene that is equivalent to the murine TIS11d gene, a member of TIS11 early response gene family, that contains unique Cysteine-Histidine motifs. The human TIS11d gene consists of two exons and encodes a polypeptide of 492 amino acids. The insertion of the DNA fragment observed in this patient is located at the carboxy-terminal portion of the TIS11d protein.