InterPro domain: IPR005539

Homeobox genes, which encode homeodomain (HD) transcriptionfactors, are known to be key regulators of both plant and animal development.In plants homeobox genes are divided into several groups by sequences, one ofwhich is the KNOX (for knotted1-type homeobox) family. Proteins of this familyshare other conserved domains, the KNOX domain and ELK domain, which isimmediately upstream of the HD. The ELK domain spans ~21 amino acids and wasdubbed for a highly conserved series of Glu, Leu, and Lys amino acids. Itcould function as a nuclear localization signal. The ELK domain also isconsidered to act as a protein-protein interaction domain, but the preciserole of this domain has not been determined [ 1 , 2 , 3 , 4 ].

The ELK domain contains repeating hydrophobic residues and has been predictedto form an amphipathic helix [ 5 ].

1. Sequence analysis and expression patterns divide the maize knotted1-like homeobox genes into two classes. Plant Cell 6, 1877-87
2. The conserved KNOX domain mediates specificity of tobacco KNOTTED1-type homeodomain proteins. Plant Cell 11, 1419-32
3. Functional analysis of the conserved domains of a rice KNOX homeodomain protein, OSH15. Plant Cell 13, 2085-98
4. Organ-specific alternative transcripts of KNOX family class 2 homeobox genes of rice. Gene 288, 41-7