Functional dissection of the ETS transcription factor MEF.
We previously indicated that myeloid elf-1-like factor (MEF) but not elf-1, specifically activated lysozyme gene expression in epithelial cells. MEF is highly homologous at the nucleotide and amino acid level, with elf-1 especially in the ETS domain. Here, we report the functional analysis of the nuclear localization and transactivation properties of MEF. To investigate the intracellular localization of MEF, we transiently transfected MEF-green fluorescence protein (GFP) fusion protein expression vector into HeLa cells. A region spanning residues 177-291 is required for nuclear localization. We produced deletion mutants of MEF to determine the transactivation domain. The data showed that the N-terminal region, encompassing amino acids 1-52 is a potent transactivation domain. The C-terminal region spanning residues 477-663 can also mediate transactivation but not as strongly as the N-terminal region. The activity of the amino acid residues 1-52 was confirmed by experiments with fused constructs of MEF to the DNA binding-domain of the yeast GAL4 protein. These results, which determined the localization of the functional domains of MEF, will provide us with new clues to its transactivation mechanisms to regulate lysozyme gene expression in epithelial cells.
Suico
Mary Ann
MA
Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Kumamoto 862-0973, Japan.
Koyanagi
Takashi
T
Ise
Satoko
S
Lu
Zhuo
Z
Hisatsune
Akinori
A
Seki
Yoshiyuki
Y
Shuto
Tsuyoshi
T
Isohama
Yoichiro
Y
Miyata
Takeshi
T
Kai
Hirofumi
H
D021581:Active Transport, Cell Nucleus; D001665:Binding Sites; D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D004847:Epithelial Cells / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D009113:Muramidase / Q000235:genetics; D019913:Nuclear Localization Signals; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D050783:Proto-Oncogene Proteins c-ets; D017384:Sequence Deletion; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015533:Transcriptional Activation
D004268:DNA-Binding Proteins; C111931:ELF4 protein, human; D019913:Nuclear Localization Signals; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D014157:Transcription Factors; D009113:Muramidase