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Specific interactions between the K domains of AG and AGLs, members of the MADS domain family of DNA binding proteins
Author(s) -
Fan HuaYing,
Hu Yi,
Tudor Matthew,
Ma Hong
Publication year - 1997
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1997.12050999.x
Subject(s) - agamous , fusion protein , biology , mads box , protein domain , protein–protein interaction , encode , dna binding protein , immunoprecipitation , function (biology) , plasma protein binding , arabidopsis , dna binding domain , genetics , cyclic nucleotide binding domain , microbiology and biotechnology , gene , peptide sequence , transcription factor , recombinant dna , mutant
Summary MADS domain (for M CM1, A G, D EFA and S RF) proteins are regulatory proteins found in all major eukaryotic kingdoms. Plant MADS domain regulatory proteins have a region of moderate sequence similarity that has been designated as the K domain, and its predicted coiled‐coil structure suggests a role in establishing a protein—protein interaction. In vivo studies with the Arabidopsis AGAMOUS (AG) protein have indicated that the K domain is important for AG function. Using a bait fusion protein containing the K domain and the C‐terminal region of AG in a yeast two‐hybrid selection, 156 clones that encode potential AG‐interacting proteins were identified. These clones each encode one of four highly related MADS domain proteins: AGL2, AGL4, AGL6 and AGL9. Additional analysis showed that the K domain of AG alone was able to bind the K domains of these AGLs. This binding was further confirmed by immunoprecipitation experiments using in vitro synthesized AG and AGL K domains. These results strongly suggest that AG interacts with AGL2, AGL4, AGL6 and AGL9 in vivo . Based on these results and previous observations, it is proposed that the AG function requires interaction with at least one of these AGL proteins, and such interactions contribute to the functional specificity of the AG protein.