Splicing factor SRP20 is a novel partner of BCL6 in a t(3;6)(q27;p21) translocation in transformed follicular lymphoma

The BCL6 gene mapped at chromosome band 3q27 encodes a zinc-finger transcri ption factor and is frequently rearranged and deregulated in B-cell non-Hod gkin's lymphoma (NHL) by promiscuous chromosomal translocations which invol ve diverse genes. We identified a novel t(3;6)(q27;p21) in a follicular lym phoma (FL) with histologic evidence of transformation and, by cloning the t ranslocation junction, determined that the SRP20 gene was the partner. In t his translocation, the 5' regulatory region of the BCL6 was substituted by a putative regulatory region of SRP20. Previously, we hypothesized that sub stitution of BCL6 promoter by those of the partner genes that were constitu tively expressed throughout B-cell development led to persistent and inappr opriate expression of BCL6. We examined the expression pattern of SRP20 dur ing B-cell development by Northern blot analysis of a panel of B-cell lines representing various stages of B-cell development and noted that SRP20 mRN A was expressed throughout B-cell development. The SRP20 gene plays an impo rtant role in regulation of pre-mRNA splicing, and is expressed specificall y in lymphoid tissues. This study provides the first evidence of SRP20 gene rearrangement in human hematopoietic malignancies. (C) 2001 Wiley-Liss, In c.