title: The Arabidopsis thaliana SET-domain-containing protein ASHH1/SDG26 interacts with itself and with distinct histone lysine methyltransferases.
abstract: Polycomb group (PcG) and trithorax group (trxG) proteins are key regulators of homeotic genes and have central roles in cell proliferation, growth and development. In animals, PcG and trxG proteins form higher order protein complexes that contain SET domain proteins with histone methyltransferase activity, and are responsible for the different types of lysine methylation at the N-terminal tails of the core histone proteins. However, whether H3K4 methyltransferase complexes exist in Arabidopsis thaliana remains unknown. Here, we make use of the yeast two-hybrid system and the bimolecular fluorescence complementation assay to provide evidence for the self-association of the Arabidopsis thaliana SET-domain-containing protein SET DOMAIN GROUP 26 (SDG26), also known as ABSENT, SMALL, OR HOMEOTIC DISCS 1 HOMOLOG 1 (ASHH1). In addition, we show that the ASHH1 protein associates with SET-domain-containing sequences from two distinct histone lysine methyltransferases, the ARABIDOPSIS HOMOLOG OF TRITHORAX-1 (ATX1) and ASHH2 proteins. Furthermore, after screening a cDNA library we found that ASHH1 interacts with two proteins from the heat shock protein 40 kDa (Hsp40/DnaJ) superfamily, thus connecting the epigenetic network with a system sensing external cues. Our findings suggest that trxG complexes in Arabidopsis thaliana could involve different sets of histone lysine methyltransferases, and that these complexes may be engaged in multiple developmental processes in Arabidopsis.
authors.affiliation: Departamento de Ingeniería Genética, CINVESTAV Unidad Irapuato, Km. 9.6 Libramiento Norte, Carretera Irapuato-León, C.P. 36821, Irapuato, Guanajuato, Mexico.
authors.forename: María del Pilar
authors.initials: Mdel P
authors.lastname: Valencia-Morales
authors.forename: José Alberto
authors.initials: JA
authors.lastname: Camas-Reyes
authors.forename: José Luis
authors.initials: JL
authors.lastname: Cabrera-Ponce
authors.forename: Raúl
authors.initials: R
authors.lastname: Alvarez-Venegas
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D018506:Gene Expression Regulation, Plant; D005801:Genes, Homeobox; D006360:Heat-Shock Proteins / Q000378:metabolism*; D011495:Histone-Lysine N-Methyltransferase / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; D006360:Heat-Shock Proteins; D011495:Histone-Lysine N-Methyltransferase