MLLT2, AF-4 protein, Proto-oncogene AF4, FEL protein

MLLT2 is involved in acute leukemias through a chromosomal translocation t(4;11)(q21;q23) that involves mllt2 and mll/hrx. AF-4 (MLLT2), AF-9, and ENL proteins contain nuclear targeting sequences as well as serine-rich and proline-rich regions. Stretches abundant in basic amino acids are also present in the three proteins. These results suggest that the different proteins fused to ALL-1 polypeptide(s) provide similar functional domains. AF4 is a serine- and proline-rich putative transcription factor with a glutamine-rich carboxyl terminus. The composition of the complete MLL-AF4 fusion product argues that it may act through either a gain-of-function or a dominant negative mechanism in leukemogenesis.