PlantTFDB
Plant Transcription Factor Database
v4.0
Previous version: v1.0, v2.0, v3.0
Citrullus lanatus
HD-ZIP Family
Species TF ID Description
Cla010169HD-ZIP family protein
Cla008339HD-ZIP family protein
Cla005620HD-ZIP family protein
Cla003103HD-ZIP family protein
Cla021107HD-ZIP family protein
Cla010341HD-ZIP family protein
Cla017553HD-ZIP family protein
Cla015276HD-ZIP family protein
Cla014061HD-ZIP family protein
Cla000198HD-ZIP family protein
Cla014127HD-ZIP family protein
Cla021121HD-ZIP family protein
Cla018360HD-ZIP family protein
Cla017743HD-ZIP family protein
Cla020900HD-ZIP family protein
Cla010153HD-ZIP family protein
Cla018880HD-ZIP family protein
Cla003908HD-ZIP family protein
Cla014193HD-ZIP family protein
Cla014541HD-ZIP family protein
Cla000111HD-ZIP family protein
Cla017080HD-ZIP family protein
Cla002419HD-ZIP family protein
Cla010488HD-ZIP family protein
Cla007677HD-ZIP family protein
Cla012669HD-ZIP family protein
Cla015453HD-ZIP family protein
Cla016237HD-ZIP family protein
Cla019400HD-ZIP family protein
Cla018652HD-ZIP family protein
Cla000893HD-ZIP family protein
Cla006197HD-ZIP family protein
Cla014465HD-ZIP family protein
Cla021261HD-ZIP family protein
Cla019523HD-ZIP family protein
Cla009826HD-ZIP family protein
Cla006925HD-ZIP family protein
Cla003413HD-ZIP family protein
Cla008739HD-ZIP family protein
Cla013146HD-ZIP family protein
Cla023107HD-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