High impact information on ATHB-3

• The Arabidopsis thaliana Athb-1 is a homeobox gene of unknown function [1].
• The sequence shows distinct similarities specifically to the KNOX (knotted-like homeobox) class of homeobox genes known from different angiosperm plants [2].
• The ASYMMETRIC LEAVES2 gene of Arabidopsis thaliana regulates formation of a symmetric lamina, establishment of venation and repression of meristem-related homeobox genes in leaves [3].
• These findings suggest that, in leaves, the AS2 and AS1 genes repress the expression of these homeobox genes, which are thought to maintain the indeterminate cell state in the shoot apical meristem [3].
• Requirement of homeobox gene STIMPY/WOX9 for Arabidopsis meristem growth and maintenance [4].

Biological context of ATHB-3

• A unique feature of late-flowering fwa epigenetic mutations is that the phenotype is caused by ectopic expression of the homeobox gene FWA [5].
• The class 1 KNOTTED1-like homeobox (KNOX) genes such as knotted1 (kn1) in maize (Zea mays) and SHOOTMERISTEMLESS in Arabidopsis (Arabidopsis thaliana) play a role in maintaining shoot apical meristem indeterminacy, and their misexpression is sufficient to induce cell division and meristem formation [6].
• In higher plants, class I KNOTTED1-like homeobox (KNOX) gene suppression and leaf polarity establishment are two processes crucial for leaf morphogenesis [7].
• Transcripts of some class 1 KNOX homeobox genes, which are thought to be related to meristem functions, and cell cycle regulating genes were ectopically accumulated in mature leaves [8].

Associations of ATHB-3 with chemical compounds

• The Arabidopsis genes have an unusual structure in that they have a leucine zipper motif adjacent to the carboxy terminal region of the homeo domain, a feature not found in homeobox-containing genes isolated from animals [9].

Other interactions of ATHB-3

• We have isolated a homeobox-containing gene from Arabidopsis thaliana using a degenerate oligonucleotide probe corresponding to the most conserved region of the homeodomain [9].
• Taken together, our results suggest that AS2 and AS1 might be involved in establishment of a prominent midvein and of networks of other veins as well as in the formation of the symmetric leaf lamina, which might be related to repression of class 1 knox homeobox genes in leaves [3].
• Using the Athb-3 clone as a probe we have isolated cDNA clones corresponding to three novel homeodomain-leucine zipper proteins [10].
• The homeobox gene GLABRA2 (GL2) has been considered a key component, acting farthest downstream in this regulation [11].

References