Arabidopsis thaliana contains two differentially expressed 3-hydroxy-3-methylglutaryl-CoA reductase genes, which encode microsomal forms of the enzyme.

Enjuto, Montserrat; Balcells, Lluı́s; Campos, Narciso; Caelles, Carmé; Arró, Montserrat; Boronat, Albert

doi:10.1073/pnas.91.3.927

Cited by 177 publications

(171 citation statements)

References 42 publications

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“…Aside from suberin, phellem imperviousness has been attributed to the associated waxes, which in cork consist mainly of isoprenoids such as triterpenes and sterols (Castola et al 2005). This is in agreement with the cork oak upregulation of the gene coding for 3-hydroxy-3-methylglutaryl coenzyme A reductases (HMGR1), which catalyses the first rate-limiting step in the isoprenoid biosynthesis (Enjuto et al 1994) and with the upregulation of several genes related to wax biosynthesis (Table S6A), hence suggesting a higher accumulation of these compounds in the outer bark of cork oak.…”

Section: Discussionmentioning

confidence: 55%

A comparative transcriptomic approach to understanding the formation of cork

et al. 2017

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Key message The transcriptome comparison of two oak species reveals possible candidates accounting for the exceptionally thick and pure cork oak phellem, such as those involved in secondary metabolism and phellogen activity. Abstract Cork oak, Quercus suber, differs from other Mediterranean oaks such as holm oak (Quercus ilex) by the thickness and organization of the external bark. While holm oak outer bark contains sequential periderms interspersed with dead secondary phloem (rhytidome), the cork oak outer bark only contains thick layers of phellem (cork rings) that accumulate until reaching a thickness that allows industrial uses. Here we compare the cork oak outer bark transcriptome with that of holm oak. Both transcriptomes present similitudes in their complexity, but whereas cork oak external bark is enriched with upregulated genes related to suberin, which is the main polymer responsible for the protective function of periderm, the upregulated categories of holm oak are enriched in abiotic stress and chromatin assembly. Concomitantly with the upregulation of suberin-related genes, there is also induction of regulatory and meristematic genes, whose predicted activities agree with the increased number of phellem layers found in the cork oak sample. Further transcript profiling among different cork oak tissues and conditions suggests that cork and wood share many regulatory mechanisms, probably reflecting similar ontogeny. Moreover, the analysis of transcripts accumulation during the cork growth season showed that most regulatory genes are upregulated early in the season when the cork cambium becomes active. Altogether our work provides the first transcriptome comparison between cork oak and holm oak outer bark, which unveils new regulatory candidate genes of phellem development.

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Section: Discussionmentioning

confidence: 55%

A comparative transcriptomic approach to understanding the formation of cork

et al. 2017

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“…HMGR from many plant species has been characterized, and its activity has been shown to be regulated by different physiological and environmental stimuli, such as phytohormones, light, wounding, pathogen attack, feedback mechanisms, and endogenous protein factors (for reviews, see Bach et al, 1991aBach et al, , 1991bStermer et al, 1994). Although the intracellular site(s) of mevalonate synthesis has been a matter of controversy for many years (Gray, 1987), recent data support the hypothesis that, in higher plants, the formation of mevalonate occurs solely in the cytosol (Enjuto et al, 1994).…”

Section: Introductionmentioning

confidence: 75%

“…Arabidopsis (Caelles et al, 1989;Enjuto et al, 1994), three genes have been reported in Hevea brasiliensis (Chye et al, 1992), and four genes are present in tomato . Larger HMGR gene families have been reported in wheat (Aoyagi et al, 1993), pea (Monfar et al, 1990 and A. Boronat, unpublished results), and potato (Stermer et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

Expression of the Arabidopsis HMG2 gene, encoding 3-hydroxy-3-methylglutaryl coenzyme A reductase, is restricted to meristematic and floral tissues.

et al. 1995

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M o n t s e r r a t Enjuto,' Victoria Lumbreras, Carles Marín, a n d A l b e r t B o r o n a t 2 Unitat de Bioquímica i Biologia Molecular A, Departament de Bioquímica i Fisiologia, Facultat de Química, Universitat de Barcelona, 08028 Barcelona, SpainThe synthesis of mevalonate, which is considered the first rate-limiting step in isoprenoid biosynthesis, is catalyzed by the enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR; EC 1.1.1.34). In Arabidopsis, HMGR is encoded by two differentially expressed genes (HMG1 and HMGP). The transcriptional activity of the HMGP gene was studied after fusing different regions of its 5' flanking region to the P-glucuronidase (GUS) reporter gene and transforming the resulting constructs into tobacco plants. The spatial and temporal expression directed by the HMGP promoter in the transgenic plants is consistent with the expression pattern previously established by RNA analysis using an HMGBspecific probe. HMGP expression is restricted to meristematic (root tip and shoot apex) and floral (secretory zone of the stigma, mature pollen grains, gynoecium vascular tissue, and fertilized ovules) tissues. Deletion analysis of the HMGP 5'flanking region was conducted in transgenic plants and transfected protoplasts. The region containing nucleotides -857 to +64 of the HMGP gene was sufficient to confer high levels of expression in both floral and meristematic tissues, although deletion to nucleotide -503 resulted in almost complete loss of expression. Sequences contained within the 5' transcribed, untranslated region are also important for gene expression. The biological significance of the restricted pattern of expression of HMGP is also discussed.

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“…In the prophase, 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) catalyzes mevalonate synthesis from HMG-CoA, which is considered the most important committed step of the MVA pathway (Choi et al, 1992). Subsequently, in the metaphase, farnesyl diphosphate synthase (FPPS), a representative and crucial enzyme, condenses IPP and DMAPP to form the key direct precursor, Farnesyl diphosphate (FPP) (Enjuto et al, 1994). After a branchpoint intermediate for various terpenoids based on FPP, Squalene Synthase (SQS) drives the synthesis of triterpenoids, sterols and cholesterols.…”

Section: Fig 1 Triterpenoid Biosynthetic Pathway In Ganoderma Cellsmentioning

confidence: 99%

<i>In silico</i> Analysis of three Committed-Steps Involved in Triterpenoid Biosynthesis from <i>Ganoderma lucidum</i>

Shui¹,

Lan²,

Wei³

2016

American Journal of Biochemistry and Biotechnology

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Ganoderma lucidum is widely considered as one of the most valuable Traditional Chinese Medicines, with various bioactive constituents and pharmaceutical effects. Triterpenoids are important effective ingredients of G. lucidum, which are synthesized mainly through the mevalonate pathway. In this study, we aimed to characterize and analyze three committed-step enzymes of the mevalonate pathway, 3-Hydroxy-3-Methylglutaryl-Coenzyme A Reductase (HMGR), Farnesyl Diphosphate Synthase (FPPS) and Squalene Synthase (SQS), using various bioinformatic tools and servers. As a results, the molecular structures and physicochemical properties of the proteins and their encoding genes (Glhmgr, Glfpps and Glsqs) were studied. The GlHMGR and GlFPPS proteins are localized in the cytosol and lack any transmembrane topological structures. By contrast, GlSQS enters the secretory pathway via its transit peptide and has three transmembrane helices. Phylogenetic analysis suggested that the three proteins could be classified into three large groups according to their significant functional association and genetic conservation. The secondary structures of the GlHMGR, GlFPPS and GlSQS comprise mainly α-helixes and random coils and the three tertiary structures were modeled successfully, including the identification of key motifs. Additionally, the expression levels of the three genes were compared on the basis of dbEST records. In conclusion, the results demonstrated that HMGR, FPPS and SQS from G. Lucidum have typical molecular structures and functions. In addition, we inferred that GlFPPS might be the perfect target for genetic engineering because of its position in a bottleneck step, as revealed by metabolic flux analysis.

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Arabidopsis thaliana contains two differentially expressed 3-hydroxy-3-methylglutaryl-CoA reductase genes, which encode microsomal forms of the enzyme.

Cited by 177 publications

References 42 publications

A comparative transcriptomic approach to understanding the formation of cork

A comparative transcriptomic approach to understanding the formation of cork

Expression of the Arabidopsis HMG2 gene, encoding 3-hydroxy-3-methylglutaryl coenzyme A reductase, is restricted to meristematic and floral tissues.

<i>In silico</i> Analysis of three Committed-Steps Involved in Triterpenoid Biosynthesis from <i>Ganoderma lucidum</i>

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