This is a homeobox transcription factor KN domain conserved from fungi to human and plants. They were first identified as TALE homeobox genes in eukaryotes, (including KNOX and MEIS genes) [1,2,3]. They have been recently classified [4,5,6].

1: Expression patterns of class I KNOX and YABBY genes in Ruscus aculeatus (Asparagaceae) with implications for phylloclade homology. Hirayama Y, Yamada T, Oya Y, Ito M, Kato M, Imaichi R; Dev Genes Evol. 2007;217:363-372. PMID:17429685

2: A novel homeobox protein which recognizes a TGT core and functionally interferes with a retinoid-responsive motif. Bertolino E, Reimund B, Wildt-Perinic D, Clerc RG; J Biol Chem. 1995;270:31178-31188 PMID:8537382

3: Analysis of TALE superclass homeobox genes (MEIS, PBC, KNOX, Iroquois, TGIF) reveals a novel domain conserved between plants and animals. Burglin TR; Nucleic Acids Res 1997;25:4173-4180. PMID:9336443

4: Comprehensive analysis of animal TALE homeobox genes: new conserved motifs and cases of accelerated evolution. Mukherjee K, Burglin TR; J Mol Evol. 2007;65:137-153. PMID:17665086

5: A comprehensive classification and evolutionary analysis of plant homeobox genes. Mukherjee K, Brocchieri L, Burglin TR; Mol Biol Evol. 2009;26:2775-2794. PMID:19734295

6: Homeodomain subtypes and functional diversity. Burglin TR; Subcell Biochem. 2011;52:95-122. PMID:21557080