Identification of Hox gene downstream genes at embryonic stages 11 and 12<br></br><br></br>Functional diversification of body parts is dependent on the formation of specialized structures along the various body axes. In animals, region-specific morphogenesis along the anterior-posterior axis is controlled by a group of conserved transcription factors encoded by the Hox genes. Although it has long been assumed that Hox proteins carry out their function by regulating distinct sets of downstream genes, only a small number of such genes have been found, with very few having direct roles in controlling cellular behavior. We have quantitatively identified hundreds of Hox downstream genes in Drosophila by microarray analysis, and validated many of them by in situ hybridizations on loss- and gain-of-function mutants. One important finding is that Hox proteins, despite their similar DNA binding properties in vitro, have highly specific effects on the transcriptome in vivo, as expression of many downstream genes responds primarily to a single Hox protein. In addition, a large fraction of downstream genes encodes realizator functions, which directly affect morphogenetic processes, such as orientation and rate of cell divisions, cell-cell adhesion and communication, cell shape and migration, or cell death. Focusing on these realizators, we provide a framework for the morphogenesis of the maxillary segment. Since the genomic organization of Hox genes and the interaction of Hox proteins with specific cofactors are conserved in vertebrates and invertebrates, and similar classes of downstream genes are regulated by Hox proteins across the metazoan phylogeny, our findings represent a first step towards a mechanistic understanding of morphological diversification within a species as well as between species.
Comparative analysis of Hox downstream genes in Drosophila.
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View SamplesAbove ground tissue of 10 day old Arabidopsis seedlings of Col wild-type, 35S-ARR7, arr7, 35S-ARR15 was treated with Cytokinin (benzyladenine), Auxin (indole-3-acetic acid) or both.
Hormonal control of the shoot stem-cell niche.
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View Samplescomparison of Landsberg errecta wild-type with slm mutants in apex and flowers
DETORQUEO, QUIRKY, and ZERZAUST Represent Novel Components Involved in Organ Development Mediated by the Receptor-like Kinase STRUBBELIG in Arabidopsis thaliana
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View SamplesResponse of control (flc-3) and dominant late flowering mutant (smz-D flc-3) to inductive photoperiod (tissue: apices)
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View SamplesComparison of expression profiles between greenworms and wildtype looking plants
A triplet expansion associated genetic defect in Arabidopsis thaliana
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View SamplesResponse of Arabidopsis control (flc-3) and a dominant repressor of flowering (smz-D flc-3) to inductive photoperiod
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View SamplesAfter zygote division, the resulting daughter cells progressively give rise to two very different tissue types. With the use of microarrays, global nuclear expression profiles were generated.
Cell type-specific transcriptome analysis in the early Arabidopsis thaliana embryo.
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View Sampleswild-type and mutant seedlings were grown on various Nitrogen sources
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View SamplesTo monitor gene expression changes pre floral transition and during early flower development col-0 and tps1-2 GVG::TPS1 (von Dijken, 2004) plants were grown under SD (8 hr light, 16 hr dark) for 21 days. Plants were then shifted to LD (16 hr light, 8 hr dark) conditions to induce flowering. RNA was isolated from micro-dissected apical tissue harvested 0 and 5 days after the shift to LD and double-stranded cDNA was synthesized. Biotinylated cRNA probes were prepared and hybridized to the Affymetrix ATH1 array in duplicate (biological replicates).
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View SamplesMicroarray analysis of wild type plants and plants with reduced (ago1-27 and se-1) or increased miR156 levels (se-1 p35S:MIR156). Shoot apices were dissected from 20-day-old, short-day grown plants.
miR156-regulated SPL transcription factors define an endogenous flowering pathway in Arabidopsis thaliana.
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