K. Ohno et al., Characterization of a Drosophila homologue of the human myelodysplasia/myeloid leukemia factor (MLF), GENE, 260(1-2), 2000, pp. 133-143
The transcription factor DREF regulates proliferation-related genes in Dros
ophila. With two-hybrid screening using DREF as a bait, we have obtained a
clone encoding a protein homologous to human myelodysplasia/myeloid leukemi
a factor 1 (hMLF1). We termed the protein Drosophila MLF (dMLF); it consist
s of a polypeptide of 309 amino acid residues, whose sequence shares 23.1%
identity with hMLF1. High conservation of 54.2% identity over 107 amino aci
ds was found in the central region. The dMLF gene was mapped to 52D on the
second chromosome by in situ hybridization. Interaction between dMLF and DR
EF in vitro could be confirmed by glutathione S-transferase pull-down assay
, with the conserved central region appearing to play an important role in
this. Northern blot hybridization analysis revealed dMLF mRNA levels to be
high in unfertilized eggs, early embryos, pupae and adult males, and relati
vely low in adult females and larvae. This fluctuation of mRNA during Droso
phila development is similar to that observed for DREF mRNA, except in the
pupa and adult male. Using a specific antibody against the dMLF, we perform
ed immunofluorescent staining of Drosophila Kc cells and showed a primarily
cytoplasmic staining, whereas DREF localizes in the nucleus. However, dMLF
protein contains a putative 14-3-3 binding motif involved in the subcellul
ar localization of various regulatory molecules, and interaction with DREF
could be regulated through this motif. The transgenic fly data suggesting t
he genetic interaction between DREF and dMLF support this possibility. Char
acterization of dMLF in the present study provides the molecular basis for
analysis of its significance in Drosophila. (C) 2000 Elsevier Science B.V.
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