Analysis by atomic force microscopy of Med8 binding to cis-acting regulatory elements of the SUC2 and HXK2 genes of saccharomyces cerevisiae.
Med8 protein is a regulator that specifically binds to upstream activating sequences (UASs) of SUC2 promoter, to downstream repressing sequences (DRSs) of the HXK2 gene and to the carboxy-terminal domain of the RNA polymerase II. Atomic force microscopy has allowed for direct visualization of Med8 interactions with a 305 bp fragment of SUC2 promoter and with a 676 bp fragment of HXK2 gene, containing respectively the UASs and DRSs regulatory regions. This approach has provided complementary information about the position and the structure of the DNA-protein complexes. Med8 binding to DNA results in total covering of one of the two existing 7 bp motives (consensus, (A/C)(A/G)GAAAT) in the studied DNA fragments. No preference for binding either of the two UASs of SUC2 promoter as well as for the two DRSs of HXK2 gene has been found. We also discuss whether this protein works as dimer or as a monomer.
Moreno-Herrero
F
F
Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Biotecnología de Asturias, Universidad de Oviedo, 33006, Oviedo, Spain.
Herrero
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P
Colchero
J
J
Baró
A M
AM
Moreno
F
F
D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D004271:DNA, Fungal / Q000378:metabolism; D004926:Escherichia coli; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D026901:Membrane Transport Proteins; D018625:Microscopy, Atomic Force / Q000379:methods; D010940:Plant Proteins / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000502:physiology; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*
D002352:Carrier Proteins; D004271:DNA, Fungal; D005656:Fungal Proteins; D026901:Membrane Transport Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; C078729:sucrose transport protein, plant; D012319:RNA Polymerase II