Nonrandom fusion of L-plastin(LCPI) and LAZ3(BCL6) genes by t(3;13)(q27;q14) chromosome translocation in two cases of B-cell non-Hodgkin lymphoma

The LAZ3(BCL6) gene on chromosome band 3q27 is nonrandomly disrupted; in B- cell non-Hodgkin lymphoma (B-NHL) by chromosomal translocations clustered w ithin a 3.3-kb MTC (major translocation cluster) located between the two fi rst noncoding exons. These translocations generally result in the expressio n of a chimeric mRNA transcript between the LAZ3 gene and sequences derived from the partner chromosome. Using RACE RT-PCR, we previously demonstrated fusion of LAZ3 with the RhoH/TTF gene, a hemopoietic cell-specific small G TPase involved in cytoskeleton organization, and with the BOB1/OBF1 gene, a B-cell-specific coactivator of octamer-binding transcription factors, foll owing translocations t(3;4)(q27;p13) and t(3;11)(q27;q23), respectively. He re we report the identification of the L-Plastin(LCP1) gene as a novel LAZ3 partner in chimeric transcripts resulting from a t(3;13)(q27;q14) transloc ation, in two cases of B-cell lymphoma. As a consequence of the translocati on, the 5' regulatory region of each gene was exchanged, creating both LCP1 -LAZ3 and reciprocal LAZ3-LCP1 fusion transcripts in one case, and only a L CP1-LAZ3 fusion transcript in the other. The 13q14 chromosome region is fre quently disrupted in various proliferative disorders, and the LCP1 gene def ines a new breakpoint site in this region. This gene encodes an actin-bindi ng protein and is the second LAZ3 partner gene, with the RhoH/TTF gene, inv olved in actin cytoskeleton organization. Genes Chromosomes Cancer 26:97-10 5, 1999. (C) 1999 Wiley-Liss, Inc.