A nucleosome interaction module is required for normal function of Arabidopsis thaliana BRAHMA.
The BRAHMA (BRM) gene encodes the SNF2-type ATPase of the putative Arabidopsis thaliana SWI/SNF chromatin remodelling complex. This family of ATPases is characterized by the presence of a conserved catalytic domain and an arrangement of auxiliary domains, whose functions in the remodelling activity remains unclear. Here, we characterize, at the molecular and functional level, the carboxy-terminal part of Arabidopsis BRM. We have found three DNA-binding regions that bind various free DNA and nucleosomal probes with different specificity. One of these regions contains an AT-hook motif. The carboxy terminus also contains a bromodomain able to bind histones H3 and H4. We propose that this array of domains constitute a nucleosome interaction module that helps BRM to interact with its substrate. We also characterize an Arabidopsis mutant that expresses a BRM protein lacking the last 454 amino acid residues (BRM-DeltaC), encompassing the bromodomain and two of the three DNA-binding activities identified. This mutant displays an intermediate phenotype between those of the wild-type and a null allele mutant, suggesting that the nucleosome interaction module is required for the normal function of BRM but it is not essential for the remodelling activity of BRM-containing SWI/SNF complexes.
Farrona
S
S
Centro Andaluz de Biología Molecular y Medicina Regenerativa and Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas, Américo Vespucio s/n, E-41092 Sevilla, Spain.
Hurtado
L
L
Reyes
J C
JC
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000502:physiology*; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D001665:Binding Sites; D004269:DNA, Bacterial / Q000378:metabolism; D018744:DNA, Plant / Q000378:metabolism; D035264:Flowers / Q000254:growth & development; D017343:Genes, Plant; D006657:Histones / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009707:Nucleosomes / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment