RESUMEN
Zinc finger proteins are the most common among families of DNA-binding transcription factors. Designer transcription factors generated by the fusion of engineered zinc finger DNA-binding domains (ZF-DBDs) to effector domains have been valuable tools for the modulation of gene expression and for targeted genome editing. However, ZF-DBDs without effector domains have also been shown to effectively modulate gene expression by competing with sequence-specific DNA-binding transcription factors. Here, we describe the methodology and provide a detailed workflow for the cloning, expression, purification, and direct cell delivery of engineered ZF-DBDs. Using this protocol, ZF-DBDs can be generated with high efficiency in less than 2 weeks. We also describe a nonradioactive method for measuring DNA binding affinity of the purified ZF-DBD proteins as well as a method for direct delivery of the purified ZF-DBDs to mammalian cells.
Asunto(s)
Proteínas de Unión al ADN/metabolismo , Factores de Transcripción/metabolismo , Animales , Sitios de Unión , Proteínas de Unión al ADN/química , Ensayo de Cambio de Movilidad Electroforética , Humanos , Unión Proteica , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Factores de Transcripción/química , Dedos de ZincRESUMEN
Reactivation of γ-globin expression has been shown to ameliorate disease phenotypes associated with mutations in the adult ß-globin gene, including sickle cell disease. Specific mutations in the promoter of the γ-globin genes are known to prevent repression of the genes in the adult and thus lead to hereditary persistence of fetal hemoglobin. One such hereditary persistence of fetal hemoglobin is associated with a sequence located 567 bp upstream of the Gγ-globin gene which assembles a GATA-containing repressor complex. We generated two synthetic zinc-finger DNA-binding domains (ZF-DBDs) targeting this sequence. The -567Gγ ZF-DBDs associated with high affinity and specificity with the target site in the γ-globin gene promoter. We delivered the -567Gγ ZF-DBDs directly to primary erythroid cells. Exposure of these cells to the recombinant -567Gγ ZF-DBDs led to increased expression of the γ-globin gene. Direct protein delivery of ZF-DBDs that compete with transcription regulatory proteins will have broad implications for modulating gene expression in analytical or therapeutic settings.