Disease relevance of REV

• Here we report the structural and functional characterisation of a dehydration responsive nuclear-targeted HDZip transcriptional regulator, CpHB-7 [1].
• Chemo-attraction was observed in Nostoc strains 8964:3 and PCC 73102 towards exudate or crushed extract of the natural hosts Gunnera manicata, Cycas revoluta and Blasia pusilla, and the nonhost plants Trifolium repens, Arabidopsis thaliana and Oryza sativa [2].

High impact information on REV

• Here we report an analysis of the DNA binding properties of the Athb-1 homeodomain-leucine zipper (HD-Zip-1) domain in vitro [3].
• Gel retardation assays demonstrated that the HD-Zip-1 domain binds to DNA as a dimer [3].
• The HD-Zip-1 domain recognizes a 9 bp dyad-symmetric sequence [CAAT(A/T)ATTG], as determined by selecting high-affinity binding sites from random-sequence DNA [3].
• The close proximity of these two domains suggests that the homeodomain-leucine zipper motif could, via dimerization of the leucine zippers, recognize dyad-symmetrical DNA sequences [4].
• The ae3 as2 double mutant displayed severely abaxialized leaves, which were accompanied by elevated levels of leaf abaxial promoting genes FILAMENTOUS FLOWER, YABBY3, KANADI1 (KAN1), and KAN2 and a reduced level of the adaxial promoting gene REVOLUTA [5].

Chemical compound and disease context of REV

• A new homeodomain-leucine zipper gene from Arabidopsis thaliana induced by water stress and abscisic acid treatment [6].

Biological context of REV

• The Arabidopsis thaliana genome contains five class III homeodomain-leucine zipper genes [7].
• We demonstrate that the jba-1D phenotypes are caused by over-expression of miR166g, and require the activity of the RNase III helicase DCL1. miR166g over-expression in jba-1D plants affects the transcripts of several class III homeodomain-leucine zipper (AtHD-ZIP) family target genes [8].
• Gene expression analysis demonstrated that the IFL1 gene is expressed in the interfascicular regions in which fibers differentiate, which is consistent with its role in the control of interfascicular fiber differentiation [9].
• CORONA, a member of the class III homeodomain leucine zipper gene family in Arabidopsis, regulates stem cell specification and organogenesis [10].
• Members of three classes of transcription factors in Arabidopsis (Arabidopsis thaliana; the Class III homeodomain/leucine zipper [HD-ZIP] proteins, KANADI proteins, and YABBY proteins) are expressed in either the adaxial or abaxial domain of organ primordia where they confer these respective identities [11].

Associations of REV with chemical compounds

• We identified the REV gene and found it encodes a predicted homeodomain/leucine zipper transcription factor that also contains a START sterol-lipid binding domain [12].
• Recent studies implicate ATHB-2, a homeodomain-leucine zipper transcription factor, as a regulator of shade-avoidance responses and establish a strong link between this factor and auxin signaling [13].
• Further, abscisic acid or water deficit treatments and different light conditions affected the transcript levels of a majority of the HDZip I genes [14].
• Induction of a homeodomain-leucine zipper gene by auxin is inhibited by cytokinin in Arabidopsis roots [15].
• In this study, we show that the avb1 mutation occurred in the putative microRNA 165 target sequence in the IFL1/REV gene and caused an amino acid substitution in the putative sterol/lipid-binding START domain [16].

Other interactions of REV

• PHB, PHV and REV transcripts contain a complementary site for miRNA165 and miRNA166, which can direct their cleavage in vitro [17].
• Loss of KANADI activity results in similar alterations in vascular patterning as compared to REVOLUTA gain-of-function alleles [18].
• Simultaneous loss-of-function of PHABULOSA, PHAVOLUTA, and REVOLUTA abaxializes cotyledons, abolishes the formation of the primary apical meristem, and in severe cases, eliminates bilateral symmetry; these phenotypes implicate these three genes in radial patterning of both embryonic and postembryonic growth [18].
• RESULTS: We show that gain-of-function alleles of REVOLUTA, another member of the class III HD-ZIP gene family, are characterized by adaxialized lateral organs and alterations in the radial patterning of vascular bundles in the stem [18].
• ZeHB-10, -11 and -12 encode for HD-Zip proteins of the class III to which Arabidopsis Athb-8, -9, -14, -15 and IFL1 belong [19].

Analytical, diagnostic and therapeutic context of REV

• Sequence analysis showed that the IFL1 gene encodes a transcription factor that has the same features as a family of homeodomain-leucine zipper (HD-ZIP) proteins found only in plants [9].
• The hybrid aspen (Populus tremulaxPopulus alba) class III HD-Zip transcription factor (PtaHB1) and microRNA 166 (Pta-miR166) family were cloned from hybrid aspen using a combination of in silico and polymerase chain reaction methods [20].

References