Premium
Two distinct mechanisms for the SCL gene activation in the t(1;14) translocation of T‐cell leukemias
Author(s) -
Bernard Olivier,
Guglielmi Paul,
Jonveaux Philippe,
Cherif Dorra,
Gisselbrecht Sylvia,
Mauchauffe Martine,
Berger Roland,
Larsen ChristianJacques,
MathieuMahul Daniele
Publication year - 1990
Publication title -
genes, chromosomes and cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.754
H-Index - 119
eISSN - 1098-2264
pISSN - 1045-2257
DOI - 10.1002/gcc.2870010303
Subject(s) - chromosomal translocation , biology , microbiology and biotechnology , locus (genetics) , gene , recombinase , genetics , gene rearrangement , t cell , breakpoint , chromosome 21 , chromosome , recombination , immune system
Abstract Molecular study of a t(1;14)(p32;q11) translocation found in an acute T‐cell leukemia (Kd cells) with a relatively mature phenotype is reported. Complex DNA rearrangements were characterized in the TCR α/δ locus. Besides a productive Vα/Jα assembly found on the normal allele, two deletions within the Jα cluster were identified in the translocated allele. The translocation breakpoints involved the TCR α gene on chromosome 14 and the SCL locus on chromosome band 1p32 that was recently shown to be activated by the t(1;14) translocation of the DU 528 leukemic cell line. Significantly, both Kd and DU 528 translocation breakpoints were located at the boundaries of Dδ or Jδ segments and were clustered in a 10 kb genomic fragment of the SCL gene. The presence of recombination signal motifs (heptamer‐12/23 bp spacer‐nonamer) on both normal chromosome partners, and N nucleotide addition on both derivative chromosomes involved the recombinase system in the translocation event. The SCL locus was highly expressed as a 5 kb transcript in Kd cells and, as already reported, as a 2 kb transcript in DU 528 cells. Importantly, a 5 kb SCL transcript was also detected in immature nonlymphoid hematopoietic cells but not in normal mature T cells, suggesting that it might correspond to the normal SCL transcript. Taken together, our data support the notion that the involvement of the SCL gene in the leukemogenic process may occur through overexpression of an apparently normal transcript (Kd cells) or expression of a truncated RNA (DU 528 cells).