105 research outputs found
The Unconserved Groucho Central Region Is Essential for Viability and Modulates Target Gene Specificity
Groucho (Gro) is a Drosophila corepressor required by numerous DNA-binding repressors, many of which are distributed in gradients and provide positional information during development. Gro contains well-conserved domains at its N- and C-termini, and a poorly conserved central region that includes the GP, CcN, and SP domains. All lethal point mutations in gro map to the conserved regions, leading to speculation that the unconserved central domains are dispensable. However, our sequence analysis suggests that the central domains are disordered leading us to suspect that the lack of lethal mutations in this region reflects a lack of order rather than an absence of essential functions. In support of this conclusion, genomic rescue experiments with Gro deletion variants demonstrate that the GP and CcN domains are required for viability. Misexpression assays using these same deletion variants show that the SP domain prevents unrestrained and promiscuous repression by Gro, while the GP and CcN domains are indispensable for repression. Deletion of the GP domain leads to loss of nuclear import, while deletion of the CcN domain leads to complete loss of repression. Changes in Gro activity levels reset the threshold concentrations at which graded repressors silence target gene expression. We conclude that co-regulators such as Gro are not simply permissive components of the repression machinery, but cooperate with graded DNA-binding factors in setting borders of gene expression. We suspect that disorder in the Gro central domains may provide the flexibility that allows this region to mediate multiple interactions required for repression
Besieged Palaeonegritics or Innovative Farmers: Historical Political Ecology of Intensive and Terraced Agriculture in West Africa and Sudan
Crescimento de mudas de Campomanesia adamantium (Cambess.) O. Berg (guavira), submetidas a três nÃveis de sombreamento e substratos
REUSE OF DAIRY WASTEWATER TREATED BY MEMBRANE BIOREACTOR AND NANOFILTRATION: TECHNICAL AND ECONOMIC FEASIBILITY
Revisão sistemática da literatura sobre as formas de mensuração do desempenho da logÃstica reversa
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