Expression and regulation of neuron-specific enolase

Neuron-specific enolase (NSE) is an isoform of the glycolytic enzyme enolase which is expressed specifically in neurons and neuroendocrine cells in the mammalian nervous system. Its onset of expression coincides with neuronal differentiation and it has therefore become established as a marker of mature, postmitotic neurons (Zomzely-Neurath, 1983). The molecular basis of neuron- specific gene expression is still poorly understood (Twyman and Jones, 1995b) and the panneuronal NSE gene thus represents an excellent model for the investigation of mechanisms responsible for neuronal gene regulation. Recently, the proximal 1.8 kbp of 5' flanking sequence from the rat NSE gene was shown to confer neuron-specific and panneuronal expression upon a heterologous gene in transgenic mice (Forss-Petter et al., 1990). This suggested that the sequence probably contained neuron-specific cis-acting elements which could be investigated using a deletion-reporter strategy in cultured cells and transgenic mice. The 1.8 kbp flanking sequence has also been shown to respond to NGF and retinoic acid in parallel with the endogenous gene (Alouani et al., 1993). In this project, the 1.8 kbp 5' flanking sequence was dissected, and various truncated derivatives were compared to the full length construct in cultured cells of neuronal and nonneuronal origin. It was shown that 255 bp of 5' flanking sequence was capable of conferring full cell type-specific regulation upon a heterologous gene, indicating the presence of neuronal c/s-acting elements within 255 bp of the transcriptional start site. Further transfection experiments, concentrating on this short proximal fragment, showed that elements responsible for neuron-specific gene expression were present in this region and in vitro analysis identified at least one specific DNA-protein interaction. Preliminary analysis of NSE gene regulation was also carried out in transgenic mice. These experiments, taken together with previous studies, showed that the level of transgene expression was variable and subject to both position and gene dosage effects. It was concluded that further analysis should be carried out in transgenic lines, preferably utilising flanking boundary elements which would protect the NSE transgenes from the position effects (to which they were highly susceptible). The impact of the transfection and transgenic experiments was discussed with respect to the published literature and ideas for future experiments were suggested

Transcriptomic analysis of Chinese yam (Dioscorea polystachya Turcz.) variants indicates brassinosteroid involvement in tuber development

Dioscorea is an important but underutilized genus of flowering plants that grows predominantly in tropical and subtropical regions. Several species, known as yam, develop large underground tubers and aerial bulbils that are used as food. The Chinese yam (D. polystachya Turcz.) is one of the few Dioscorea species that grows well in temperate regions and has been proposed as a climate-resilient crop to enhance food security in Europe. However, the fragile, club-like tubers are unsuitable for mechanical harvesting, which is facilitated by shorter and thicker storage organs. Brassinosteroids (BRs) play a key role in plant cell division, cell elongation and proliferation, as well as in the gravitropic response. We collected RNA-Seq data from the head, middle and tip of two tuber shape variants: F60 (long, thin) and F2000 (short, thick). Comparative transcriptome analysis of F60 vs. F2000 revealed 30,229 differentially expressed genes (DEGs), 1,393 of which were differentially expressed in the growing tip. Several DEGs are involved in steroid/BR biosynthesis or signaling, or may be regulated by BRs. The quantification of endogenous BRs revealed higher levels of castasterone (CS), 28-norCS, 28-homoCS and brassinolide in F2000 compared to F60 tubers. The highest BR levels were detected in the growing tip, and CS was the most abundant (439.6 ± 196.41 pmol/g in F2000 and 365.6 ± 112.78 pmol/g in F60). Exogenous 24-epi-brassinolide (epi-BL) treatment (20 nM) in an aeroponic system significantly increased the width-to-length ratio (0.045 ± 0.002) compared to the mock-treated plants (0.03 ± 0.002) after 7 weeks, indicating that exogenous epi-BL produces shorter and thicker tubers. In this study we demonstrate the role of BRs in D. polystachya tuber shape, providing insight into the role of plant hormones in yam storage organ development. We found that BRs can influence tuber shape in Chinese yam by regulating the expression of genes involved cell expansion. Our data can help to improve the efficiency of Chinese yam cultivation, which could provide an alternative food source and thus contribute to future food security in Europe

Overexpression of a pseudo-etiolated-in-light-like protein in Taraxacum koksaghyz leads to a pale green phenotype and enables transcriptome-based network analysis of photomorphogenesis and isoprenoid biosynthesis

IntroductionPlant growth and greening in response to light require the synthesis of photosynthetic pigments such as chlorophylls and carotenoids, which are derived from isoprenoid precursors. In Arabidopsis, the pseudo-etiolated-in-light phenotype is caused by the overexpression of repressor of photosynthetic genes 2 (RPGE2), which regulates chlorophyll synthesis and photosynthetic genes.MethodsWe investigated a homologous protein in the Russian dandelion (Taraxacum koksaghyz) to determine its influence on the rich isoprenoid network in this species, using a combination of in silico analysis, gene overexpression, transcriptomics and metabolic profiling.ResultsHomology-based screening revealed a gene designated pseudo-etiolated-in-light-like (TkPEL-like), and in silico analysis identified a light-responsive G-box element in its promoter. TkPEL-like overexpression in dandelion plants and other systems reduced the levels of chlorophylls and carotenoids, but this was ameliorated by the mutation of one or both conserved cysteine residues. Comparative transcriptomics in dandelions overexpressing TkPEL-like showed that genes responsible for the synthesis of isoprenoid precursors and chlorophyll were downregulated, probably explaining the observed pale green leaf phenotype. In contrast, genes responsible for carotenoid synthesis were upregulated, possibly in response to feedback signaling. The evaluation of additional differentially expressed genes revealed interactions between pathways.DiscussionWe propose that TkPEL-like negatively regulates chlorophyll- and photosynthesis-related genes in a light-dependent manner, which appears to be conserved across species. Our data will inform future studies addressing the regulation of leaf isoprenoid biosynthesis and photomorphogenesis and could be used in future breeding strategies to optimize selected plant isoprenoid profiles and generate suitable plant-based production platforms

Research in graphic design

An invited and reviewed opinion piece about the current state of research in graphic/communication design