Upstream and parallel regulators of Drosophilafushi tarazu are identified by a double interaction screen.
Item
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Title
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Upstream and parallel regulators of Drosophilafushi tarazu are identified by a double interaction screen.
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Identifier
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AAI9707168
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identifier
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9707168
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Creator
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Yu, Yan.
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Contributor
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Adviser: Leslie Pick
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Date
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1996
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, Molecular
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Abstract
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fushi tarazu (ftz) gene is a homeobox containing segmentation gene required for the establishment of the segmental body pattern of the Drosophila embryo. Like other homeodomain proteins, the specificity of FTZ protein was hypothesized to be regulated by interacting with cofactors. A 323 bp ftz proximal enhancer (fPE) was shown to contain necessary information for ftz stripe formation and autoregulation. This 323 bp fPE was used to develop a yeast-based screen (Double Interaction Screen) for identifying factors that interact with FTZ to modulate its activity and factors that interact directly with binding sites in the 323 bp fPE to regulate ftz gene transcription.;FTZ-F1{dollar}\alpha{dollar} and TTK were isolated in the screen, demonstrating the validity of the selection scheme. In addition, FTZ-F1{dollar}\beta{dollar}, Sloppy paired1 (Slp1) protein, and several novel DNA-binding proteins were isolated. We showed that Slp1, a forkhead domain protein, interacts with at least one site in the 323 bp fPE, and that the 323 bp fPE mediates repression of ftz by Slp1 protein.;Two potential FTZ Interacting Proteins, FIP1 and FIP2, were isolated. FIP1 encodes FTZ-F1{dollar}\alpha{dollar}. Our experiments suggested that FTZ and FTZ-F1{dollar}\alpha{dollar} are present in the same complex in vivo, and that the two proteins bind cooperatively to target DNA. FIP2 is a novel gene. In situ hybridization revealed that FIP2 mRNA was expressed uniformly at early embryonic stages, and later restricted to the primordial endoderm cells. Preliminary data also showed that FIP2 protein selectively interacts with some homeotic gene products, suggesting it may be a co-factor for these homeotic gene products.;Using the Double Interaction Screen with a "bait" of the 323 bp fPE, we isolated some previously identified ftz regulators, several novel ftz regulators, and more importantly, two FTZ-interacting proteins. The isolation of FTZ cofactors demonstrates that the functional specificity of FTZ is indeed regulated by other proteins. Furthermore, the 323 bp fPE provides an example of the complexity of gene regulation which involves activation, repression, and cooperation. This type of complexity determines the unique identities of each cell in the developing organism.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
