AF4/FMR2 Family, Member 3 (AFF3)

AFF3 encodes a tissue-restricted nuclear transcriptional activator that is preferentially expressed in lymphoid tissue. Isolation of this protein initially defined a highly conserved LAF4/MLLT2 gene family of nuclear transcription factors that may function in lymphoid development and oncogenesis. In some ALL patients, this gene has been found fused to the gene for MLL. Multiple alternatively spliced transcript variants that encode different proteins have been found for this gene.The deduced 1,227-amino acid protein has a molecular mass of 135 kD in B-cell lines. The protein, which the authors designated LAF4 (lymphoid nuclear protein related to AF4), showed high sequence similarity, particularly in the N-terminal and C-terminal regions, with AF4 (MLTT2), the gene that is fused to the MLL gene in t(4;11)(q21;q23).