The Arabidopsis BELL1 and KNOX TALE homeodomain proteins interact through a domain conserved between plants and animals.
Interactions between TALE (three-amino acid loop extension) homeodomain proteins play important roles in the development of both fungi and animals. Although in plants, two different subclasses of TALE proteins include important developmental regulators, the existence of interactions between plant TALE proteins has remained unexplored. We have used the yeast two-hybrid system to demonstrate that the Arabidopsis BELL1 (BEL1) homeodomain protein can selectively heterodimerize with specific KNAT homeodomain proteins. Interaction is mediated by BEL1 sequences N terminal to the homeodomain and KNAT sequences including the MEINOX domain. These findings validate the hypothesis that the MEINOX domain has been conserved between plants and animals as an interaction domain for developmental regulators. In yeast, BEL1 and KNAT proteins can activate transcription only as a heterodimeric complex, suggesting a role for such complexes in planta. Finally, overlapping patterns of BEL1 and SHOOT MERISTEMLESS (STM) expression within the inflorescence meristem suggest a role for the BEL1-STM complex in maintaining the indeterminacy of the inflorescence meristem.
Bellaoui
M
M
Botany Department and Biotechnology Laboratory, 6270 University Boulevard, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
Pidkowich
M S
MS
Samach
A
A
Kushalappa
K
K
Kohalmi
S E
SE
Modrusan
Z
Z
Crosby
W L
WL
Haughn
G W
GW
D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins; D001483:Base Sequence; D017124:Conserved Sequence; D017931:DNA Primers; D015723:Gene Library; D018398:Homeodomain Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D010940:Plant Proteins; D016133:Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000235:genetics; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics*
D029681:Arabidopsis Proteins; C097235:BEL1 protein, Arabidopsis; D017931:DNA Primers; D018398:Homeodomain Proteins; D010940:Plant Proteins; D014157:Transcription Factors