The root cap-specific conversion of the auxin precursor indole-3-butyric acid (IBA) into the main auxin indole-3-acetic acid (IAA) generates a local auxin source which subsequently modulates both the periodicity and intensity of auxin response oscillations in the root tip of Arabidopsis, and consequently fine-tunes the spatiotemporal patterning of lateral roots. To explore downstream components of this signaling process, we investigated the early transcriptional regulations happening in the root tip during IBA-to-IAA conversion in Col-0 and ibr1 ibr3 ibr10 triple mutant after 6 hours of IBA treatment.
Root Cap-Derived Auxin Pre-patterns the Longitudinal Axis of the Arabidopsis Root.
Age, Specimen part, Treatment
View SamplesWe performed an analysis of transcriptomic responses to auxin within four distinct tissues of the Arabidopsis thaliana root. This high-resolution dataset shows how different cell types are predisposed to react to auxin with discrete transcriptional responses. The sensitivity provided by the analysis lies in the ability to detect cell-type specific responses diluted in organ-level analyses. This dataset provides a novel resource to examine how auxin, a widespread signal in plant development, influences differentiation and patterning in the plant through tissue-specific transcriptional regulation.
A map of cell type-specific auxin responses.
Specimen part, Treatment
View SamplesLateral root initiation was used as a model system to study the mechanisms behind auxin-induced cell division. Genome-wide transcriptional changes were monitored during the early steps of lateral root initiation. Inclusion of the dominant auxin signaling mutant solitary root1 (slr1) identified genes involved in lateral root initiation that act downstream of the AUX/IAA signaling pathway. Interestingly, key components of the cell cycle machinery were strongly defective in slr1, suggesting a direct link between AUX/IAA signaling and core cell cycle regulation. However, induction of the cell cycle in the mutant background by overexpression of the D-type cyclin (CYCD3;1) was able to trigger complete rounds of cell division in the pericycle that did not result in lateral root formation. Therefore, lateral root initiation can only take place when cell cycle activation is accompanied by cell fate respecification of pericycle cells. The microarray data also yielded evidence for the existence of both negative and positive feedback mechanisms that regulate auxin homeostasis and signal transduction in the pericycle, thereby fine-tuning the process of lateral root initiation.
Cell cycle progression in the pericycle is not sufficient for SOLITARY ROOT/IAA14-mediated lateral root initiation in Arabidopsis thaliana.
No sample metadata fields
View SamplesThe acquisition of water and nutrients by plant roots is a fundamental aspect of agriculture and strongly depends on root architecture. Root branching and expansion of the root system is achieved through the development of lateral roots and is to a large extent controlled by the plant hormone auxin. However, the pleiotropic effects of auxin or auxin-like molecules on root systems complicate the study of lateral root development. Here we describe a small-molecule screen in Arabidopsis thaliana that identified naxillin as what is to our knowledge the first non-auxin-like molecule that promotes root branching. By using naxillin as a chemical tool, we identified a new function for root cap-specific conversion of the auxin precursor indole-3-butyric acid into the active auxin indole-3-acetic acid and uncovered the involvement of the root cap in root branching. Delivery of an auxin precursor in peripheral tissues such as the root cap might represent an important mechanism shaping root architecture. To further explore the specificity of naxillin for lateral root development, we compared the early effects of naxillin at the transcriptome level with NAA (1-Naphthaleneacetic acid) in roots of 3-day-old seedlings after 2-h and 6-h treatment.
A role for the root cap in root branching revealed by the non-auxin probe naxillin.
Age, Specimen part, Treatment
View SamplesArabidopsis seedlings, of both wild-type and an ARF7/ARF19 double knockout mutant, were grown to 7 days post-germination. The roots were then dissected into 5 developmental zones, the meristem, early elongation zone, late elongation zone, mature root and lateral root zone. The sections then underwent transcriptional profiling to identify processes and regulatory events specific and in common to the zones.
A novel aux/IAA28 signaling cascade activates GATA23-dependent specification of lateral root founder cell identity.
Age, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Stellate Cells, Hepatocytes, and Endothelial Cells Imprint the Kupffer Cell Identity on Monocytes Colonizing the Liver Macrophage Niche.
No sample metadata fields
View SamplesMacrophages are strongly adapted to their tissue of residence. Yet, we know little about the cell-cell interactions that imprint the tissue-specific identities of macrophages in their respective niches. Using conditional depletion of liver Kupffer cells, we traced the developmental stages of monocytes differentiating into Kupffer cells and mapped the cellular interactions imprinting the Kupffer cell identity. Kupffer cell loss induced the tumor necrosis factor (TNF) and interleukin-1 (IL-1) receptor-dependent activation of stellate cells and endothelial cells, resulting in the transient production of chemokines and adhesion molecules orchestrating monocyte engraftment. Engrafted circulating monocytes transmigrated into the perisinusoidal space, and acquired the liver-associated transcription factors ID3 and LXRα. Coordinated interactions with hepatocytes induced ID3 expression, while endothelial cells and stellate cells induced LXRα via a synergistic NOTCH-BMP pathway. This study shows that the Kupffer cell niche is composed of stellate cells, hepatocytes and endothelial cells that together imprint the liver-specific macrophage identity.
Stellate Cells, Hepatocytes, and Endothelial Cells Imprint the Kupffer Cell Identity on Monocytes Colonizing the Liver Macrophage Niche.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The Transcription Factor ZEB2 Is Required to Maintain the Tissue-Specific Identities of Macrophages.
Specimen part
View SamplesMicroarray, Bulk RNA Sequencing and Single cell RNA Sequencing of different murine tissue-resident macrophage populations to assess role of Zeb2 and LXRa
The Transcription Factor ZEB2 Is Required to Maintain the Tissue-Specific Identities of Macrophages.
Specimen part
View SamplesIn the adult mammalian testis, spermatogenic differentiation starts from a minute population of spermatogonial stem cells (SSCs). SSCs are generated after birth from the fetal gonocytes, themselves derived from the primordial germ cells (PGCs), which are specified during the first days after implantation. Transcriptome profiling of purified preparations evidenced the preferential accumulation in SSCs of transcripts of PU.1 (Sfpi1), a regulatory gene previously identified in hematopoietic progenitors. In situ immunolabeling and RNA determination showed a complex pattern of expression in the adult testis, first in SSCs and early spermatogonia followed by de novo expression in pachytene spermatocytes.
PU.1 (Sfpi1), a pleiotropic regulator expressed from the first embryonic stages with a crucial function in germinal progenitors.
No sample metadata fields
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