t(3;11)(q21;q23) KMT2A/EEFSEC

2011-09-01   Jean-Loup Huret 

1.Genetics, Dept Medical Information, University of Poitiers, CHU Poitiers Hospital, F-86021 Poitiers, France

Clinics and Pathology

Disease

Acute leukemia

Epidemiology

Only two cases of acute leukemia to date (2 female patients); in one case, the phenotype was described: it was a case of biphenotypic acute leukemia (BAL), a B-ALL expressing CD13 (Hanson et al., 1993).

Clinics

No data.

Genes Involved and Proteins

Note
The genes involved in the translocation were determined in one case (Meyer et al., 2005).
Gene name
EEFSEC (eukaryotic elongation factor, selenocysteine-tRNA specific)
Location
3q21.3
Protein description
EEFSEC, often called SELB, is the elongation factor for delivery of selenocysteinyl-tRNA to the ribosome. Selenocysteine (Sec) is found in the active sites of enzymes, most of which are involved in redox reactions (Paleskava et al., 2010).
Gene name
KMT2A (myeloid/lymphoid or mixed lineage leukemia)
Location
11q23.3
Protein description
A major transcript of 14982 bp produces a 3969 amino acids protein from 36 of the 37 exons. Contains from N-term to C-term a binding site for MEN1, 3 AT hooks (binds to the minor grove of DNA); 2 speckled nuclear localisation signals; 2 repression domains RD1 and RD2: RD1 or CXXC: cystein methyl transferase, binds CpG rich DNA, has a transcriptional repression activity; RD2 recruits histone desacetylases HDAC1 and HDAC2; 3 plant homeodomains (cystein rich zinc finger domains, with homodimerization properties), 1 bromodomain (may bind acetylated histones), and 1 plant homeodomain; these domains may be involved in protein-protein interaction; a FYRN and a FRYC domain; a transactivation domain which binds CBP; may acetylates H3 and H4 in the HOX area; a SET domain: methyltransferase; methylates H3, including histones in the HOX area for allowing chromatin to be open to transcription. MLL is cleaved by taspase 1 into 2 proteins before entering the nucleus: a p300/320 N-term protein called MLL-N, and a p180 C-term protein, called MLL-C. The FYRN and a FRYC domains of native MLL associate MLL-N and MLL-C in a stable complex; they form a multiprotein complex with transcription factor TFIID. General transcription factor; maintains HOX genes expression in undifferentiated cells. Major regulator of hematopoiesis and embryonic development; role in cell cycle regulation.

Result of the Chromosomal Anomaly

Description

Fusion between MLL intron 9 and EEFSEC intron 1, but with no maintenance of an open reading frame. This translocation seems to create nonfunctional fusion genes.

Bibliography

Pubmed IDLast YearTitleAuthors
76878601993Acute biphenotypic leukaemia: immunophenotypic and cytogenetic analysis.Hanson CA et al
156267572005Diagnostic tool for the identification of MLL rearrangements including unknown partner genes.Meyer C et al
199401622010Thermodynamic and kinetic framework of selenocysteyl-tRNASec recognition by elongation factor SelB.Paleskava A et al

Summary

Fusion gene

KMT2A/EEFSEC KMT2A (11q23.3) EEFSEC (3q21.3) COF 2064|KMT2A/EEFSEC KMT2A (11q23.3) EEFSEC (3q21.3) TIC

Citation

Jean-Loup Huret

t(3;11)(q21;q23) KMT2A/EEFSEC

Atlas Genet Cytogenet Oncol Haematol. 2011-09-01

Online version: http://atlasgeneticsoncology.org/haematological/1407/t(3;11)(q21;q23)

External Links