Lineage specific demethylation of tal-1 gene breakpoint region determines the frequency of tal-1 deletions in alpha beta lineage T-cells.

Abstract

tal-1 deletions are caused by a site specific recombination, which exclusively occurs in 12-26% of T-cell acute lymphoblastic leukemias (T-ALL). In a previous study on a large series of T-ALL we demonstrated an apparent preferential occurrence of tal-1 deletions in CD3- and CD3+ alpha beta lineage T-ALL with TcR-delta gene deletions on one or both alleles. In the present study we investigated whether accessibility of the tal-1 deletion breakpoint regions influences the preferential occurrence in specific T-ALL subgroups. Because DNA methylation is assumed to determine accessibility of DNA for recombination, the methylation status of the tal-1 deletion type 1 breakpoint regions (sildb and taldb1) was studied. Although the sildb were completely demethylated in all T-ALL, preferential (de)methylation configurations of the taldb1 were observed in the analysed 119 T-ALL. Most TcR-alpha beta + T-ALL contained completely demethylated taldb1 (77%), whereas in most TcR-gamma delta + T-ALL partial or complete methylation occurred (42% and 47%, respectively). In T-ALL subgroups defined by different TcR-delta gene configurations also preferential taldb1 (de)methylation patterns were seen, which was most prominent in T-ALL with both TcR-delta genes deleted (84% complete demethylation). The previously observed preferential occurrence of tal-1 deletion type 1 in TcR-alpha beta + vs CD3- T-ALL and in T-ALL with both vs one TcR-delta genes deleted, disappeared when we retricted to T-ALL with completely demethylated taldb1. Moreover, all T-ALL with a tal-1 deletion type 1 (n = 15) contained completely demethylated taldb1. We therefore conclude that complete demethylation of taldb1 is a prerequisite for tal-1 deletions type 1 and that the differences in tal-1 deletion frequencies observed in the various T-ALL subgroups are caused by differences in the (de)methylation status of taldb1 in these subgroups.

• Authors: T M Breit, I L Wolvers-Tettero, J J van Dongen
• Journal: Oncogene (Oncogene) Vol. 9 Issue 7 Pg. 1847-53 (Jul 1994) ISSN: 0950-9232 [Print] England
• PMID: 8208530 (Publication Type: Journal Article)

Chemical References

• Basic Helix-Loop-Helix Transcription Factors
• CD3 Complex
• DNA Primers
• DNA, Neoplasm
• DNA-Binding Proteins
• Intracellular Signaling Peptides and Proteins
• Oncogene Proteins, Fusion
• Proteins
• Proto-Oncogene Proteins
• Receptors, Antigen, T-Cell, alpha-beta
• Receptors, Antigen, T-Cell, gamma-delta
• STIL protein, human
• T-Cell Acute Lymphocytic Leukemia Protein 1
• Transcription Factors
• TAL1 protein, human

Topics

• Base Sequence
• Basic Helix-Loop-Helix Transcription Factors
• CD3 Complex (genetics, metabolism)
• Cells, Cultured
• Child
• DNA Primers
• DNA, Neoplasm (metabolism)
• DNA-Binding Proteins (genetics, metabolism)
• Gene Deletion
• Humans
• Intracellular Signaling Peptides and Proteins
• Leukemia, B-Cell (metabolism)
• Leukemia, Myeloid, Acute (metabolism)
• Leukemia, T-Cell (metabolism)
• Methylation
• Molecular Sequence Data
• Oncogene Proteins, Fusion
• Phenotype
• Proteins (genetics, metabolism)
• Proto-Oncogene Proteins
• Receptors, Antigen, T-Cell, alpha-beta (genetics)
• Receptors, Antigen, T-Cell, gamma-delta (genetics)
• T-Cell Acute Lymphocytic Leukemia Protein 1
• T-Lymphocytes (metabolism)
• Transcription Factors
• Tumor Cells, Cultured