PlantTFDB
Plant Transcription Factor Database
v4.0
Previous version: v1.0, v2.0, v3.0
Sisymbrium irio
HD-ZIP Family
Species TF ID Description
676731350HD-ZIP family protein
676727498HD-ZIP family protein
676752354HD-ZIP family protein
676744088HD-ZIP family protein
676732518HD-ZIP family protein
676789428HD-ZIP family protein
676719170HD-ZIP family protein
676788896HD-ZIP family protein
676721122HD-ZIP family protein
676728144HD-ZIP family protein
676728430HD-ZIP family protein
676718904HD-ZIP family protein
676709428HD-ZIP family protein
676765780HD-ZIP family protein
676731394HD-ZIP family protein
676749058HD-ZIP family protein
676715502HD-ZIP family protein
676752194HD-ZIP family protein
676734764HD-ZIP family protein
676729358HD-ZIP family protein
676756700HD-ZIP family protein
676717998HD-ZIP family protein
676718002HD-ZIP family protein
676749196HD-ZIP family protein
676730684HD-ZIP family protein
676770606HD-ZIP family protein
676788000HD-ZIP family protein
676781130HD-ZIP family protein
676713604HD-ZIP family protein
676742796HD-ZIP family protein
676760600HD-ZIP family protein
676755876HD-ZIP family protein
676743386HD-ZIP family protein
676780838HD-ZIP family protein
676758872HD-ZIP family protein
676746608HD-ZIP family protein
676734570HD-ZIP family protein
676769310HD-ZIP family protein
676749604HD-ZIP family protein
676786782HD-ZIP family protein
676788622HD-ZIP family protein
676767434HD-ZIP family protein
676751386HD-ZIP family protein
676729076HD-ZIP family protein
676728350HD-ZIP family protein
676727202HD-ZIP family protein
676729804HD-ZIP family protein
676778890HD-ZIP family protein
676745746HD-ZIP family protein
676741644HD-ZIP family protein
676731158HD-ZIP family protein
HD-ZIP Family Introduction

A homeobox (HB) encodes a protein domain, the homeodomain (HD), which is a conserved 60-amino acid motif present in transcription factors found in all the eukaryotic organisms. This 60-amino acid sequence folds into a characteristic three-helix structure that is able to interact specifically with DNA. Most HDs are able to bind DNA as monomers with high affinity, through interactions made by helix III (the so-called recognition helix) and a disordered N-terminal arm located beyond helix I. The high degree of conservation of this type of domain among diverse proteins from different kingdoms indicates that this structure is crucial to maintain the HD functionality and that the role played by this domain is vital.

Members of the HD-Zip family have a leucine zipper motif (LZ) immediately downstream of the HD. The two motifs are present in transcription factors found in species belonging to other eukaryotic kingdoms, but their association in a single protein is unique to plants. The HD is responsible for the specific binding to DNA, whereas LZ acts as a dimerization motif. HD-Zip proteins bind to DNA as dimers, and the absence of LZ absolutely abolishes their binding ability, which indicates that the relative orientation of the monomers, driven by this motif, is crucial for an efficient recognition of DNA.

Ariel FD, Manavella PA, Dezar CA, Chan RL.
The true story of the HD-Zip family.
Trends Plant Sci, 2007. 12(9): p. 419-26.
PMID: 17698401