TAL2 (T-cell acute lymphoblastic leukemia 2)

2005-08-01   Katrina Vanura 

Medical University of Vienna, Dept. of Medicine I, Div. of Hematology, Waehringer Guertel 18-20, A - 1090 Vienna, Austria

Identity

HGNC
LOCATION
9q31.2
LOCUSID
ALIAS
-
FUSION GENES

DNA/RNA

Description

exons 1a, 2, 3, and 1b located 5-8 kb upstream of exon 4; coding region in exon 4 (326 bp)

Transcription

various mRNA isoforms were found in SUP-T3 and in the mouse, which also encompass upstream exons; gene products, however, always corresponded to the TAL2 protein encoded by exon 4

Proteins

Description

108 amino acids; basic Helix Loop Helix motif for protein dimerization and DNA-binding

Expression

in adult testes; in developing midbrain, dorsal diencephalon, rostroventral diencaphalic/telencephalic boundary, and anterior pons; pivotal role in the development of the mature central nervous system; not expressed during normal hematopoietic development

Function

transcription factor; TAL2 dimerizes with members of the class A subgroup of bHLH proteins (ie E47, E12, E2-2, HEB), as well as LIM-only proteins LMO1 and LMO2; heterodimers are formed intracellularly through stable interaction between bHLH domains of TAL2 and E47; TAL2/E47 heterodimers bind DNA in a sequence-specific manner that is dependent on the E-box element; TAL2/E12 heterodimers also have DNA-binding activity; TAL2 does not bind DNA in absence of E2A proteins; a significant fraction (60%) of TAL2 polypeptides from SUP-T3 exist in phosphorylated form, the rest is unphosphorylated; serine residue 100 of TAL2 is the potential site of phosphorylation by MAP kinases.

Homology

TAL1 at 1p31, LYL1 at 19p13; TAL2, TAL1, and LYL1 share more than 85% amino acid identity in the bHLH domain and are thus more related to one other than to other bHLH proteins, for instance c-myc

Implicated in

Entity name
Disease
T cell acute lymphoblastic leukemia found in < 1% of ALL, in 1-2% of T-ALL, rare but recurrent
Hybrid gene
Translocation of part of TCRB locus to a breakpoint 33 kb downstream of TAL2 mediated by the V(D)J recombinase via a fortuitous recombination signal sequence (YRSS) on chromosome 9; the translocation results in a signal joint fusion of TAL2 YRSS with the Db1 23-RSS; this gene product was detected in 6 of 10 thymus samples of healthy children with an estimated frequency of 1 in 10 million thymic cells; only upon secondary rearrangement of the TAL2/Db signal joint to the Jb2.6 segment, and deletion of the intervening sequence, the typical TAL2/Jb2.6 T-ALL junctions could be observed which presumably lead to overexpression of TAL2 and development of leukemia.
Fusion protein
TAL2 placed under control of TCRB enhancer leading to overexpression of TAL2 in T-cells and development of leukemia

Bibliography

Pubmed IDLast YearTitleAuthors
81426191993TAL1, TAL2 and LYL1: a family of basic helix-loop-helix proteins implicated in T cell acute leukaemia.Baer R et al
110717722000The T cell oncogene Tal2 is necessary for normal development of the mouse brain.Bucher K et al
125671872003Distinct t(7;9)(q34;q32) breakpoints in healthy individuals and individuals with T-ALL.Marculescu R et al
99314881999The leukemic oncogene tal-2 is expressed in the developing mouse brain.Mori S et al
25360651989Consistent breakage between consensus recombinase heptamers of chromosome 9 DNA in a recurrent chromosomal translocation of human T cell leukemia.Tycko B et al
17630561991TAL2, a helix-loop-helix gene activated by the (7;9)(q34;q32) translocation in human T-cell leukemia.Xia Y et al
81528051994Products of the TAL2 oncogene in leukemic T cells: bHLH phosphoproteins with DNA-binding activity.Xia Y et al

Other Information

Locus ID:

NCBI: 6887
MIM: 186855
HGNC: 11557
Ensembl: ENSG00000186051

Variants:

dbSNP: 6887
ClinVar: 6887
TCGA: ENSG00000186051
COSMIC: TAL2

RNA/Proteins

Gene IDTranscript IDUniprot
ENSG00000186051ENST00000334077Q16559

Expression (GTEx)

0
1

Protein levels (Protein atlas)

Not detected
Low
Medium
High

References

Pubmed IDYearTitleCitations
219717002012Correlations among ERCC1, XPB, UBE2I, EGF, TAL2 and ILF3 revealed by gene signatures of histological subtypes of patients with epithelial ovarian cancer.16
125671872003Distinct t(7;9)(q34;q32) breakpoints in healthy individuals and individuals with T-ALL.6
240867572013The T-cell oncogene Tal2 Is a Target of PU.1 and upregulated during osteoclastogenesis.1

Citation

Katrina Vanura

TAL2 (T-cell acute lymphoblastic leukemia 2)

Atlas Genet Cytogenet Oncol Haematol. 2005-08-01

Online version: http://atlasgeneticsoncology.org/gene/28/tal2