MEF2BNB-MEF2B

MEF2BNB-MEF2B Full Name

MEF2BNB-MEF2B readthrough

MEF2BNB-MEF2B Introduction

MEF2BNB-MEF2B is a chimeric read-through transcript produced by intergenic splicing between the upstream MEF2BNB gene and MEF2B on chromosome 19p13.11, the locus that encodes the MEF2B transcription factor. The protein produced from this read-through retains the MADS-box and MEF2 domains of MEF2B and gains additional N-terminal residues contributed by MEF2BNB. Read-through transcripts of this type are typically expressed at low levels, but they can acquire dominant or modulatory activity if they perturb the stoichiometry of the MEF2B-containing transcription complexes.

Figure 1. The structure of MEF2BNB-MEF2B.

Modulation of MEF2-Driven Transcriptional Programs
MEF2B is itself a relatively weak transcriptional activator compared with its paralogs MEF2A, -C, and -D, but it is required for the expression of BCL6, IRF4, and other regulators of germinal-center B-cell identity. The MEF2BNB–MEF2B chimeric protein retains the DNA-binding and dimerization surfaces of MEF2B while altering the regulatory N-terminus, which influences its interactions with co-repressors (HDAC4/5/7/9) and co-activators (EP300, CABIN1). Read-through expression therefore has the potential to fine-tune MEF2B target-gene output in cell types where both transcripts are produced.

Diffuse Large B-Cell Lymphoma
The MEF2B locus is recurrently mutated in diffuse large B-cell lymphoma (DLBCL), particularly in the germinal-center B-cell (GCB) subtype, where gain-of-function mutations in the MADS-box/MEF2 domain enhance BCL6 expression and drive lymphomagenesis. The MEF2BNB–MEF2B read-through has been observed in DLBCL cell lines and patient samples, where its contribution to transcriptional dysregulation is under active investigation. Routine diagnostic panels for B-cell lymphomas now include sequencing of the MEF2B coding region, and MEF2B-driven expression signatures are being developed as prognostic biomarkers in DLBCL.

Alternate Names for MEF2BNB-MEF2B

MEF2BNB-MEF2B; MEF2BNB-MEF2B readthrough; MEF2B; LOC729991-MEF2B; myocyte enhancer factor 2B; LOC729991-MEF2B readthrough;