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We have characterized an Arabidopsis homeobox gene coding for a putative DNA binding protein that represents an early marker for vascular development. The full-length cDNA encodes a protein of 833 amino acids that we have designated Athb-8; it contains the conserved DNA binding domain that characterizes the HD-Zip family of transcription factors. RNA(More)
The root-hair pattern of Arabidopsis is determined through a regulatory circuit composed of transcription factor genes. The homeobox gene GLABRA2 (GL2) has been considered a key component, acting farthest downstream in this regulation. GL2 modified to include a transactivating function caused epidermal cells to develop ectopic root hairs or root hair-like(More)
Plants grown under dense canopies perceive through the phytochrome system a reduction in the ratio of red to far-red light as a warning of competition, and this triggers a series of morphological changes to avoid shade. Several phytochrome signaling intermediates acting as positive regulators of accelerated elongation growth and induction of flowering in(More)
The ATHB-2 gene encoding an homeodomain-leucine zipper protein is rapidly and strongly induced by changes in the ratio of red to far-red light which naturally occur during the daytime under the canopy and induce in many plants the shade avoidance response. Here, we show that elevated ATHB-2 levels inhibit cotyledon expansion by restricting cell elongation(More)
The Arabidopsis Athb-1 and -2 proteins are characterized by the presence of a homeodomain (HD) with a closely linked leucine zipper motif (Zip). We have suggested that the HD-Zip motif could, via dimerization of the leucine zippers, recognize dyad-symmetric DNA sequences. Here we report an analysis of the DNA binding properties of the Athb-1(More)
We report the isolation and characterization of two Arabidopsis homeobox genes highly related to the Athb-8 gene. The full-length cDNAs encode proteins of 841 and 852 amino acids which we have designated Athb-9 and -14, respectively. Athb-8, -9 and -14 are members of a small family of HD-Zip proteins (HD-ZIP III) characterized by a HD-Zip motif confined to(More)
The Arabidopsis genome contains 10 genes belonging to the HD-Zip II family including ATHB2 and HAT2. Previous work has shown that ATHB2 is rapidly and strongly induced by light quality changes that provoke the shade avoidance response whereas HAT2 expression responds to auxin. Here, we present a genome-wide analysis of the HD-Zip II family. Phylogeny(More)
ATHB-8, -9, -14, -15, and IFL1/REV are members of a small homeodomain-leucine zipper family whose genes are characterized by expression in the vascular tissue. ATHB-8, a gene positively regulated by auxin (Baima et al., 1995), is considered an early marker of the procambial cells and of the cambium during vascular regeneration after wounding. Here, we(More)
The Arabidopsis homeobox gene ATHB-2 is tightly regulated by light signals, and is thought to direct morphological changes during shade avoidance responses. To understand how ATHB-2 mediates light signals in plant morphogenesis, we investigated its transcriptional network. We constructed a gene encoding a chimeric transcription factor (HD-Zip-2-V-G) that is(More)
Homeodomain-leucine zipper (HD-Zip) proteins are putative transcription factors identified only in plants. Related Arabidopsis homeobox genes, isolated by virtue of sequence conservation within the helix-3 region of the homeodomain, fall into four families based on sequence similarity. This paper reports the characterization of Athb-10, a 747 amino acid(More)