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Molecular characterization of novel reciprocal translocation t(6;14) in an Epstein-Barr virus-transformed B cell
Abstract:
An in vitro culture of FLEB14 cells, an Epstein-Barr virus-transformed B cell precursor containing the germ line immunoglobulin genes, gave rise to a uniclonally expanded variant, FLEB14 delta 3, which was rearranged at the immunoglobulin heavy-chain gene locus. Cytogenetic analysis showed that FLEB14 delta 3 had a novel reciprocal translocation, t(6;14)(q15;q32). Molecular cloning of the rearranged DNA fragments and determination of their nucleotide sequence revealed that the recombination event was reciprocal, imprecise, and nonhomologous and took place in the S mu region, like those found in Burkitt's lymphoma cells. We propose a molecular model to explain this genetic event which may be relevant to class switch recombination. The translocated sequence of chromosome 6 did not contain any known oncogenes, although the sequence is conserved among mammals. FLEB14 delta 3 did not show tumorigenicity.
Insights
Researchers identified a novel genetic translocation in Epstein-Barr virus-transformed B cells. This event, occurring in the S mu region, may offer insights into class switch recombination mechanisms in B-cell malignancies.
Area of Science:
- Immunology
- Molecular Biology
- Genetics
- Cell Biology
Background:
- Epstein-Barr virus (EBV) transformation of B cells is a model for studying B-cell development and genetic alterations.
- Immunoglobulin heavy-chain gene locus rearrangements are critical events in B-cell differentiation and are implicated in various lymphoid malignancies.
- Class switch recombination (CSR) is a normal physiological process in B cells, but errors can lead to chromosomal translocations.
Purpose of the Study:
- To characterize the genetic and molecular basis of a novel reciprocal translocation, t(6;14)(q15;q32), observed in an EBV-transformed B cell line (FLEB14 delta 3).
- To investigate the mechanism of this recombination event and its potential relevance to class switch recombination.
- To assess the oncogenic potential of the translocated sequence on chromosome 6.
Main Methods:
- In vitro culture of EBV-transformed B cell line (FLEB14) and isolation of a variant (FLEB14 delta 3) with immunoglobulin heavy-chain gene locus rearrangement.
- Cytogenetic analysis to identify the specific chromosomal translocation t(6;14)(q15;q32).
- Molecular cloning and nucleotide sequencing of the rearranged DNA fragments to determine the precise recombination breakpoints and mechanism.
Main Results:
- A uniclonally expanded variant, FLEB14 delta 3, exhibited a novel reciprocal translocation, t(6;14)(q15;q32), at the immunoglobulin heavy-chain gene locus.
- The recombination event was reciprocal, imprecise, and nonhomologous, occurring in the S mu region, similar to events in Burkitt's lymphoma.
- The translocated sequence from chromosome 6 did not contain known oncogenes and showed conservation across mammalian species; FLEB14 delta 3 was non-tumorigenic.
Conclusions:
- The identified t(6;14)(q15;q32) translocation in FLEB14 delta 3 provides a model for studying nonhomologous recombination events in B cells.
- The mechanism of recombination in the S mu region suggests potential parallels with class switch recombination pathways.
- Further investigation into this conserved sequence and its role in B-cell genetics may elucidate mechanisms underlying lymphoid malignancies.