Genetic and molecular characterization of murine GATA-1 in Aspergillus defines a critical role for the N-terminal finger.
We have utilized Aspergillus nidulans as a model system for the characterization of the major vertebrate transcription factor GATA-1. This has been achieved both by analysing the function of murine GATA-1 directly and by using direct gene replacement to introduce chimaeric areA::GATA-1 derivatives at the areA locus, which encodes a GATA factor involved in regulating nitrogen metabolism in A. nidulans. Although GATA-1 shows only limited function when expressed in A. nidulans, the C-terminal GATA DNA-binding domain can replace the native GATA domain of AREA and retain near wild-type function. Surprisingly, inclusion of the N-terminal DNA-binding domain of GATA-1 has a major role in determining the function of areA::GATA constructs in vivo, leading to a general loss of activation. This negative function is partially dominant and is dependent on both the fidelity of the zinc-chelating structure and a second factor encoded by A. nidulans. The presence of two GATA domains also disrupts modulation of AREA activity. The ability of duplicate GATA domains to disrupt normal signal transduction is not dependent on the relative position of the domains or on the fidelity of the zinc-chelating structure. This demonstrates the utility of nitrogen metabolism's regulation in A. nidulans as a model system for the molecular and genetic characterization of heterologous GATA factors while also providing insights into native Aspergillus regulatory components.
School of Biological Sciences, Gene Structure and Function Group, Donnan Laboratories, University of Liverpool, UK.
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Caddick
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Peters
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Hooley
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Nayler
D000595:Amino Acid Sequence; D000818:Animals; D001233:Aspergillus nidulans / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary; D004268:DNA-Binding Proteins / Q000235:genetics*; D050981:Erythroid-Specific DNA-Binding Factors; D005656:Fungal Proteins / Q000235:genetics; D050982:GATA1 Transcription Factor; D015870:Gene Expression; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D010641:Phenotype; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors / Q000235:genetics*; D014170:Transformation, Genetic; D016335:Zinc Fingers
C079728:AreA protein, Aspergillus nidulans; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D005656:Fungal Proteins; D050982:GATA1 Transcription Factor; C494689:Gata1 protein, mouse; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D009565:Nitrate Reductases; D050901:Nitrate Reductase; D009584:Nitrogen