The pentapeptide motif of Hox proteins is required for cooperative DNA binding with Pbx1, physically contacts Pbx1, and enhances DNA binding by Pbx1.
AUTOR(ES)
Knoepfler, P S
RESUMO
The vertebrate Hox genes, which represent a subset of all homeobox genes, encode proteins that regulate anterior-posterior positional identity during embryogenesis and are cognates of the Drosophila homeodomain proteins encoded by genes composing the homeotic complex (HOM-C). Recently, we demonstrated that multiple Hox proteins bind DNA cooperatively with both Pbx1 and its oncogenic derivative, E2A-Pbx1. Here, we show that the highly conserved pentapeptide motif F/Y-P-W-M-R/K, which occurs in numerous Hox proteins and is positioned 8 to 50 amino acids N terminal to the homeodomain, is essential for cooperative DNA binding with Pbx1 and E2A-Pbx1. Point mutational analysis demonstrated that the tryptophan and methionine residues within the core of this motif were critical for cooperative DNA binding. A peptide containing the wild-type pentapeptide sequence, but not one in which phenylalanine was substituted for tryptophan, blocked the ability of Hox proteins to bind cooperatively with Pbx1 or E2A-Pbx1, suggesting that the pentapeptide itself provides at least one surface through which Hox proteins bind Pbx1. Furthermore, the same peptide, but not the mutant peptide, stimulated DNA binding by Pbx1, suggesting that interaction of Hox proteins with Pbx1 through the pentapeptide motif raises the DNA-binding ability of Pbx1.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=230833Documentos Relacionados
- Structural determinants within Pbx1 that mediate cooperative DNA binding with pentapeptide-containing Hox proteins: proposal for a model of a Pbx1-Hox-DNA complex.
- The hexapeptide LFPWMR in Hoxb-8 is required for cooperative DNA binding with Pbx1 and Pbx2 proteins.
- Cooperative interactions between HOX and PBX proteins mediated by a conserved peptide motif.
- HMG1 interacts with HOX proteins and enhances their DNA binding and transcriptional activation.
- PBX and MEIS as Non-DNA-Binding Partners in Trimeric Complexes with HOX Proteins