이지영 교수

Transcriptional programs that regulate development are exquisitely controlled in space and time. Elucidating these programs that underlie development is essential to understanding the acquisition of cell and tissue identity. We present microarray expression profiles of a high-resolution set of developmental time points within a single Arabidopsis root and a comprehensive map of nearly all root cell types. These cell type-specific transcriptional signatures often predict previously unknown cellul

Understanding how the expression of transcription factor (TF) genes is modulated is essential for reconstructing gene regulatory networks. There is increasing evidence that sequences other than upstream noncoding can contribute to modulating gene expression, but how frequently they do so remains unclear. Here, we investigated the regulation of TFs expressed in a tissue-enriched manner in Arabidopsis roots. For 61 TFs, we created GFP reporter constructs driven by each TF's upstream noncoding sequ

Nectaries are secretory organs that are widely present in flowering plants that function to attract floral pollinators. Owing to diversity in nectary positions and structures, they are thought to have originated multiple times during angiosperm evolution, with their potential contribution to the diversification of flowering plants and pollinating animals being considerable. We investigated the genetic basis of diverse nectary forms in eudicot angiosperm species using CRABS CLAW (CRC), a gene req

CRABS CLAW (CRC), a member of the YABBY gene family, is required for nectary and carpel development. To further understand CRC regulation in Arabidopsis thaliana, we performed phylogenetic footprinting analyses of 5' upstream regions of CRC orthologs from three Brassicaceae species, including Arabidopsis. Phylogenetic footprinting efficiently identified functionally important regulatory regions (modules), indicating that CRC expression is regulated by a combination of positive and negative regul

Understanding the pattern of speciation in a group of plants is critical for understanding its morphological evolution. Lepidium is the genus with the largest variation in floral structure in Brassicaceae, a family in which the floral ground plan is remarkably stable. However, flowers in more than half of Lepidium species have reduced stamen numbers, and most of these also have reduced petals. The species with reduced flowers are geographically biased, distributed mostly in the Americas and Aust

The basic floral ground plan is remarkably constant across Brassicaceae. However, within Lepidium (ca. 175 species), deviations from this ground plan are common, with over half of Lepidium species having only two stamens rather than the usual six and a further eighth of the species having only four stamens. Furthermore, petals are reduced in size in a majority of Lepidium species. In order to determine the frequency and direction of changes in floral structure within Lepidium, we have inferred t

The plasticity of plant development relies on its ability to balance growth and stress resistance. To do this, plants have established highly coordinated gene regulatory networks (GRNs) of the transcription factors and signaling components involved in developmental processes and stress responses. In root crops, yields of storage roots are mainly determined by secondary growth driven by the vascular cambium. In relation to this, a dynamic yet intricate GRN should operate in the vascular cambium,

Asymmetric cell division (ACD) and positional signals play critical roles in the tissue patterning process. In the Arabidopsis (<i>Arabidopsis thaliana</i>) root meristem, two major phloem cell types arise via ACDs of distinct origins: one for companion cells (CCs) and the other for proto- and metaphloem sieve elements (SEs). The molecular mechanisms underlying each of these processes have been reported; however, how these are coordinated has remained elusive. Here, we report a new phloem develo

Plant growth depends on stem cell niches in meristems. In the root apical meristem, the quiescent center (QC) cells form a niche together with the surrounding stem cells. Stem cells produce daughter cells that are displaced into a transit-amplifying (TA) domain of the root meristem. TA cells divide several times to provide cells for growth. SHORTROOT (SHR) and SCARECROW (SCR) are key regulators of the stem cell niche. Cytokinin controls TA cell activities in a dose-dependent manner. Although the

This study suggests that a submicrobial dose of doxycycline as an adjunct therapy with SRP might be safe and effective in the long-term management of chronic periodontitis.

We present an improved method to quantify viral DNA in human cells at the single- molecule level. Human papilloma virus (HPV)-16 DNA was hybridized to probes that were covalently bound to a glass surface and detected with a single-molecule imaging system. In the single-probe mode, the whole genome and target DNA were fluorescently labeled before hybridization. In the dual-probe mode, a second probe was introduced that has a fluorescently labeled 1-kb DNA strand connected to the 50-nt probe seque

In this paper, we propose a noise reduction method and an adaptive contrast enhancement for local tone mapping (TM). The proposed local TM algorithm compresses the luminance of high dynamic range (HDR) image and decomposes the compressed luminance of HDR image into multi-scale subbands using the discrete wavelet transform. For noise reduction, the decomposed images are filtered using a bilateral filter and soft-thresholding. And then, the dynamic ranges of the filtered subbands are enhanced by c

The complete genome sequences of two representative species of flowering plants, the monocot rice ( Oryza sativa ) and the eudicot Arabidopsis ( Arabidopsis thaliana ), provide us with a new opportunity to understand developmental and physiological events at the genome level ([Arabidopsis Genome

Xylem development in the <i>Arabidopsis</i> root apical meristem requires a complex cross talk between plant hormone signaling and transcriptional factors (TFs). The key processes involve fine-tuning between neighboring cells, mediated <i>via</i> the intercellular movement of signaling molecules. As an example, we previously reported that AT-HOOK MOTIF NUCLEAR LOCALIZED PROTEIN (AHL) 4 (AHL4), a member of the 29 AT-hook family TFs in <i>Arabidopsis</i>, moves into xylem precursors from their nei