抄録
Myeloid leukemia factor 1 (MLF1) was first identified as part of a leukemic fusion protein produced by a chromosomal translocation, and MLF family proteins are present in many animals. In mammalian cells, MLF1 has been described as mainly cytoplasmic, but in Drosophila, one of the dMLF isoforms (dMLFA) localized mainly in the nucleus and the other isoform (dMLFB) that appears to be produced by the alternative splicing displays both nuclear and cytoplasmic localization. To investigate the difference in subcellular localization between MLF family members, we examined the subcellular localization of deletion mutants of dMLFA isoform. The analyses showed that the C-terminal 40 amino acid region of dMLFA is necessary and sufficient for nuclear localization. Based on amino acid sequences, we hypothesized two nuclear localization signals (NLSs) within the region. Site-directed mutagenesis of critical residues within the two putative NLSs leads to loss of nuclear localization, suggesting that both NLS motifs are necessary for nuclear localization.
