Molecular analysis of a chromosomal translocation, t(9;14)(p13;q32), in a diffuse large-cell lymphoma cell line expressing the Ki-1 antigen.

Abstract

We have studied a translocation, t(9;14) (pl3;q32), in a diffuse large-cell lymphoma cell line, KIS-1, that expresses the Ki-1 (CD30) antigen. Molecular cloning of the immunoglobulin heavy-chain locus (IGH) of this cell line revealed an unknown segment linked 5' to IGH. The breakpoint on chromosome 14 was 265 base pairs downstream from the 3' border of the JH6 joining gene segment. Class switch recombination deleted most of the constant genes of IGH (CH) and juxtaposed the Ca2 gene downstream of the translocation junction. Analysis of somatic cell hybrids and in situ chromosomal hybridization demonstrated that the translocated segment was normally located at band p13 of chromosome 9. The chromosome 9 sequences were transcriptionally active, giving rise to transcripts of =11 kilobases. The KIS-1 cells seemed to have a small quantity of chimeric transcripts containing both chromosome 9 and Ca2 sequences.A significant correlation has been observed between recurrent chromosomal translocations involving band 14q32, and the histologic and immunologic subtypes of human lymphoid malignancies (1)(2)(3). For example, the t(8;14)(q24;q32) is found in most cases of small-noncleaved-cell lymphoma, and the t(14;18)(q32;q21) is primarily associated with follicular small-cleaved-cell lymphoma. The lymphoma cells characterized by each of these translocations show B-cell immu-

Oncogenic role of Pax5 in the T-lymphoid lineage upon ectopic expression from the immunoglobulin heavy-chain locus

“…29 Here we have described the characterization of an IgH P5ki knock-in mouse that reproduces the specific structural and regulatory features of the t(9;14)(p13;q32) translocation identified in the human KIS-1 lymphoma. 9,10,24 One important difference between this knock-in mouse and the corresponding human lymphoma is the fact that the PAX5 insertion in the IgH P5ki allele corresponds to a germline mutation, whereas the IgH-PAX5 translocation in human lymphomas arises in germinal center B cells during late B-cell development. [9][10][11] Consequently, the inserted PAX5 gene is transcribed in all IgH-expressing cells of the knock-in mouse, which contrasts with the exclusive expression of the endogenous Pax5 gene in the B-lymphoid lineage of wild-type mice.…”

“…9,10,24 To this end, we generated a human PAX5 minigene containing 1807 bp of its 5Ј flanking sequences and linked this gene via an internal ribosome entry sequence (IRES) to the green fluorescent protein (GFP) gene ( Figure 1A). The PAX5-IRES-GFP expression cassette was inserted into the mouse IgH locus adjacent to the intronic E enhancer in such a way that the D H Q52 element and all 4 J H segments were deleted, thus resulting in a nonfunctional IgH allele ( Figure 1A).…”

Low-Grade B-Cell Lymphomas With Plasmacytic Differentiation Lack PAX5 Gene Rearrangements

“…4,5 The presence of a t(9;14) was confirmed by conventional karyotype and FISH analysis, including whole chromosome paint probes for chromosomes 9 and 14 (Vysis, Downers Grove, IL) and the core binding factor ␤ (CBFB) break-apart probe specific for band 16q22 (Vysis). The karyotype was further supported by use of the Chromoprobe Multiprobe System, Octachrome whole chromosome paint assay (Cytocell Ltd., Adderbury, Banbury, UK).…”

“…Initially described in a CD30-positive diffuse large B-cell lymphoma cell line, KIS-1, 4 this translocation involves the paired homeobox-5 (PAX5) gene at 9p13 and the immunoglobulin heavy chain (IgH) gene at 14q32. 5 After its initial characterization, further studies found the t(9;14)(p13;q32) associated with LPL. 6,7 Encoding B-cell-specific activator protein, a B-cell transcription factor, the PAX5 gene has been thought to contribute to the development of lymphoma when brought into close proximity of the IgH.…”

“…9 The heterogeneity of lymphomas associated with t(9;14) is also illustrated by previous reports of sequenced PAX5 breakpoints as shown in Figure 1: a plasmacytoid small lymphocytic lymphoma (1052), 6 a splenic marginal zone lymphoma (MZL-1), 10 a diffuse large B-cell lymphoma (895), 8,11 ␣-heavy chain disease (MAL), 12,13 and the KIS-1 cell line. 4,5 Given the frequency of low-grade B-cell lymphomas other than LPL associated with t(9;14), we chose to investigate the incidence of the PAX5 gene rearrangement in a series of low-grade B-cell lymphomas with an emphasis on plasmacytic differentiation. We developed a dual-color break-apart bacterial artificial chromosome (BAC) probe spanning all previously sequenced PAX5 rearrangements ( Figure 1).…”