The development of trichomes (leaf hairs) from pluripotent epidermal cells in Arabidopsis provides a powerful system to investigate the regulatory motifs involved in plant cell differentiation. Genetic studies have revealed that a bHLH transcription factor, GL3, activates downstream genes required for trichome initiation by interacting with a R2R3-MYB protein, GL1. In order to investigate genome-wide regulatory functions of GL1 and GL3, we performed genome-wide expression analyses using GR inducible systems of GL1 and GL3.
A systems approach reveals regulatory circuitry for Arabidopsis trichome initiation by the GL3 and GL1 selectors.
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View SamplesThe development of trichomes (leaf hairs) from pluripotent epidermal cells in Arabidopsis provides a powerful system to investigate the regulatory motifs involved in plant cell differentiation. Genetic studies have revealed that a bHLH transcription factor, GL3, activates downstream genes required for trichome initiation by interacting with a R2R3-MYB protein, GL1. We have taken advantage of several mutants in the trichome developmental pathway and gene expression analyses to identify a set of genes expressed predominantly in Arabidopsis trichomes.
A systems approach reveals regulatory circuitry for Arabidopsis trichome initiation by the GL3 and GL1 selectors.
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View SamplesTotal RNA from trichomes of fifth and sixth rosette leaves of three-week-old wild-type and gtl1-1 mutants (Figure 3B) were extracted. We found a total number of 1,759 genes, corresponding to 1,694 probes on the ATH1 chip, that show differential expression of at least 1.3-fold. Out of these 1,694 genes, 47.2% are positively regulated and 52.8% are negatively regulated by GTL1.
Transcriptional repression of the APC/C activator CCS52A1 promotes active termination of cell growth.
Specimen part
View SamplesTo understand how atypical bHLH, INCREASED LEAF INCLINATION1 (ILI1)-BINDING bHLH-1 (IBH1) (At2g43060), and close homologue, IBH1-like1 (IBL1) (At4g30410), interact to regulate cell elongation, genome-wide RNA-Seq expression analyses of IBH1 and IBL1 gain-(IBH1OE, IBL1OE) and loss-of-function (ibh1 (SALK 049177), ibl1(SALK 119457)) mutants were conducted. Overall design: For loss-of-function mutant, homozygous ibh1(SALK 049177) and ibl1(SALK 119457) were compared to wild type (Col). For gain-of-function mutant, homozygous 35Spro:IBH1-GFP and 35Spro:IBL1-GFP were compared to wild type (Col). Total RNAs were extactced from seedling of each genotypes. For each genotype two biological replicates were sequenced.
Helix-loop-helix/basic helix-loop-helix transcription factor network represses cell elongation in Arabidopsis through an apparent incoherent feed-forward loop.
Specimen part, Subject
View SamplesHow plants determine the final size of growing cells is an important, yet unanswered question. Root hairs provide an excellent model system to study this question since their final cell size is remarkably constant under given environmental conditions. In this study we demonstrate that a trihelix transcription factor GT-2-LIKE1 (GTL1) and its homolog DF1 repress root hair growth in Arabidopsis. Our transcriptional data, combined with genome-wide chromatin binding data, show that GTL1 and DF1 directly bind the RSL4 promoter and regulate its expression to repress root hair growth. Our data further show that GTL1 and RSL4 regulate each other as well as a set of common downstream genes, many of which have previously been implicated in root hair growth. This study therefore uncovers a core regulatory module that fine-tunes the extent of root hair growth by orchestrated actions of opposing transcription factors.
GTL1 and DF1 regulate root hair growth through transcriptional repression of <i>ROOT HAIR DEFECTIVE 6-LIKE 4</i> in <i>Arabidopsis</i>.
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View SamplesRegulation of spatiotemporal gene expression in higher eukaryotic cells is critical for the precise and orderly development of undifferentiated progenitors into committed cell types of the adult. Recently, dynamic epigenomic regulation, including chromatin remodeling and histone modifications by transcriptional coregulator complexes, has been shown to be involved in transcriptional regulation. Precisely how these coregulator complexes exert their cell-type and developing stage-specific activity is largely unknown. In this study, we aimed to isolate the histone demethylase LSD1 complex from neural cells by biochemical purification. In so doing, we identified MyT1 as a novel LSD1 complex component. MyT1 is a neural cell-specific zinc finger factor and it forms a stable multiprotein complex with LSD1 through direct interaction. Target gene analysis using microarray and ChIP assays revealed several genes, including PTEN, that were directly regulated by the LSD1-MyT1 complex. Knockdown of either LSD1 or MyT1 derepressed the expression of endogenous target genes and inhibited cell proliferation of a neuroblastoma cell line, Neuro2a. We propose that formation of tissue-specific combinations of coregulator complexes is a critical mechanism for tissue-specific transcriptional regulation.
Identification of myelin transcription factor 1 (MyT1) as a subunit of the neural cell type-specific lysine-specific demethylase 1 (LSD1) complex.
Cell line, Treatment
View SamplesMice lacking the function of the PcG protein CBX2 (also known as M33) show defects in gonadal, adrenal, and splenic development. In particular, XY knockout mice develop ovaries but not testes, and the gonads are hypoplastic in both sexes.
Cbx2, a polycomb group gene, is required for Sry gene expression in mice.
Specimen part
View SamplesWe demonstrate that PKA signalling drives zonal conversion within adult adrenocortical lineage in a sexually dimorphic manner. Our data establish that Prkar1a genetic ablation (leading to constitutive PKA activation) in the adult adrenocortical lineage leads to endocrine hyperactivity and accelerates adrenal cortex renewal. This results in increased zona fasciculata differentiation and final conversion into reticularis-like zone. This phenomenon relies partly on sex-dependent mechanisms of cortical renewal, on which the male androgenic milieu exerts a repressive action through induction of WNT signalling, which in turn antagonizes PKA signalling and cortical cell turnover.
PKA signaling drives reticularis differentiation and sexually dimorphic adrenal cortex renewal.
Sex, Specimen part
View SamplesSeries of samples studying effect of knock out Emx2 in urogenital epithelium of mouse embryos at E10.5.
Abnormal epithelial cell polarity and ectopic epidermal growth factor receptor (EGFR) expression induced in Emx2 KO embryonic gonads.
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View SamplesP1 encodes an R2R3-MYB transcription factor responsible for the accumulation of insecticidal flavones in maize silks and red phlobaphene pigments in pericarps and other floral tissues, which contributed to making P1 an important visual marker since the dawn of modern genetics. We conducted RNA-Seq using pericarps at two different stages, 14 and 25 days after pollination (DAP). High-throughput sequencing using the Illumina platform resulted in the generation of ~20 million high quality reads, from which ~90% aligned to the recently completed maize genome sequence corresponding to ~5 million reads for each one of the four samples. Overall design: Examination of two different RNA samples from two different stages of maize pericarp tissues.
A genome-wide regulatory framework identifies maize pericarp color1 controlled genes.
Specimen part, Subject
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