You are here: Home / Theory / Gene knockdown by RNA interference. The complete genome of Tribolium has been sequenced. This means that we know exactly from which bases the DNA is build and in which order. Although it is good to have this information, it does not tell us anything about the function of certain parts of the DNA. I wrote earlier that protein is made from RNA and that RNA is made. This feature is not available right now. Please try again later
Introduction. In 1998 Fire and coll. coined the term RNA interference (RNAi) referring to the phenomenon of post-translational silencing of gene expression that occurs in response to the introduction of double-stranded RNA (dsRNA) into a cell .This phenomenon can result in highly specific suppression of gene expression RNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression or translation, by neutralizing targeted mRNA molecules. Historically, RNAi was known by other names, including co-suppression, post-transcriptional gene silencing (PTGS), and quelling.The detailed study of each of these seemingly different processes elucidated that the identity of these phenomena. A gene knockdown is when gene expression is reduced but not completely eliminated. CRISPR and TALENs are used to perform gene knockouts or introduce genetic mutations whereas RNAi is used for gene. Over the past decade RNA interference (RNAi) has emerged as a natural mechanism for silencing gene expression. This ancient cellular antiviral response can be exploited to allow specific inhibition of the function of any chosen target gene. RNAi is proving to be an invaluable research tool, allowing much more rapid characterization of the function of known genes RNAi mechanism | RNA interference pathway using siRNA and shRNA - Duration: 14 short interfering RNA mediated gene silencing - Duration: 19:31. Shomu's Biology 94,329 views. 19:31 . 3) Cell.
Die RNA-Interferenz (kurz RNAi oder auch RNA-Silencing) ist ein natürlicher Mechanismus in den Zellen von Lebewesen mit einem Zellkern (), welcher der zielgerichteten Abschaltung von Genen dient. Sie ist ein Spezialfall der Gen-Stilllegung.Die RNA-Interferenz beruht auf einer Wechselwirkung kurzer Stücke von Ribonukleinsäure (RNA) mit der Erbinformation-übertragenden mRNA unter Beteiligung. RNA interference (RNAi) is a biological process by which double-stranded RNA (dsRNA) induces sequence-specific gene silencing by targeting mRNA for degradation. As a tool for knocking down the expression of individual genes post transcriptionally, RNAi has been widely used to study the cellular function of genes. In this chapter, I describe procedures for using gene-specific, synthetic, short. RNA interference (RNAi) is an important process, used by many different organisms to regulate the activity of genes. This animation explains how RNAi works and introduces the two main players. Gene silencing is the regulation of gene expression in a cell to prevent the expression of a certain gene. Gene silencing can occur during either transcription or translation and is often used in research. In particular, methods used to silence genes are being increasingly used to produce therapeutics to combat cancer and other diseases, such as infectious diseases and neurodegenerative disorders
RNA interference (RNAi) is the process by which the expression of a target gene is effectively silenced or knocked down by the selective inactivation of its corresponding mRNA by double-stranded RNA (dsRNA). RNAi is activated by dsRNA species delivered to the cytoplasm of cells. The silencing mechanisms can either lead to the degradation of a target mRNA, as induced by small interfering RNAs. RNA Interference: Biology, Mechanism, and Applications Article · Literature Review (PDF Available) in Microbiology and Molecular Biology Reviews 67(4):657-85 · January 2004 with 8,762 Read Small interference RNA, plasmid-, and virus-encoded short-hairpin RNA are now regular reagents in the tool box of biologists to knockdown the expression of specific genes posttranscriptionally. Efforts have also been made to develop RNA interference based therapeutics into reality. Many concerns about the RNA interference technique have now been answered through research and development. RNA interference (RNAi) - also known as post-transcriptional gene silencing, RNA silencing or quelling - is an organisms response to being infected with exogenous genetic material whether it be DNA or RNA. This mechanism allows the organism to interfere with the foreign genetic sequence before it is able to integrate itself into the host genome and cause damage. Recently, this mechanism has. . The technique is cutely called knockdown not knockout because you aren't necessarily eliminating all RNA translation. And so what does that mean if you don't see an effe..
gene silencing [PTGS]/RNA interference [RNAi]). Although there is a mechanistic connection between TGS and PTGS, TGS is an emerging ﬁeld while PTGS is undergoing an explo-sion in its information content. Here, we have limited our discussion to PTGS/RNAi-related phenomena. Pioneering observations on PTGS/RNAi were reported in plants, but later on RNAi-related events were described in almost. Schau Dir Angebote von Interference auf eBay an. Kauf Bunter! Riesenauswahl an Markenqualität. Folge Deiner Leidenschaft bei eBay RNA interference (RNAi) - Phenotypic effect after injection of single-stranded or double-stranded unc-22 RNA into the gonad of C. elegans. - The unc-22 gene encodes a myofilament protein. - Decrease in unc-22 activity is known to produce severe twitching movements. - Injected double-stranded RNA, but not single-stranded RNA, induced th Mechanisms of RNA interference 4. Biological role of RNA silencing 5. Applications of RNA silencing 6. miRNAs 1. History and definitions. Posttranscriptional gene silencing (PTGS)Posttranscriptional gene silencing (PTGS) Classical key experiment in petunia: • Artificially introduced 2 nd CHS gene • Expected: more intense flowers Real outcome: Variable phenotypes, including white flowers.
RNA interference (RNAi) is a biological process conserved across plants and animals wherein gene expression is controlled through a mechanism mediated by small 20-30 nucleotide complementary. Benitec combines the power of RNAi interference with the durability of expression from gene therapy delivery to permanently silence disease causing genes. This powerful combination provides a platform to create novel therapeutics for the treatment of human disease. RNA interference (RNAi) is an evolutionarily conserved mechanism of sequence-specific gene silencing mediated by small interfering.
The rde-1 gene, RNA interference, and transposon silencing in C. elegans. Cell 99 , 123-132 (1999). CAS Article PubMed Google Schola Effective and stable knockdown of multiple gene targets by RNA interference is often necessary to overcome isoform redundancy, but it remains a technical challenge when working with intractable cell systems. We have developed a flexible platform using RNA polymerase II promoter-driven expression of microRNA-like short hairpin RNAs which permits robust depletion of multiple target genes from a. RNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression or translation, by neutralizing targeted mRNA molecules. RNAi can be used for identification and validation of drug targets as well as in the discovery of cell-signaling pathways that are vital to organism survival and disease control. This technology is crucial to the development of new therapeutic. RNA interference often abbreviated as RNAi, is a process in which the exogenous and endogenous RNA degraded, which consequence in gene silencing. In the year 1993, Andrew Fire and Craig Mello postulated the mechanism of RNA interference by introducing the exogenous dsRNA into the C. elegans RNA interference (RNAi) is a well-established technology that revolutionized the way that researchers study mammalian gene expression and continues to contribute valuable insights into gene function today. RNAi has had significant impact on the ease, speed, and specificity with which the loss of gene function analysis can be done in mammalian cells and animal models and has long been a method.
Improving the efficiency of RNA interference in mammals. Nat. Rev. Genet. 5, 355. Shalem, et al. (2014). Genome-scale CRISPR-Cas9 knockout screening in human cells. Science 343, 84. Wang, et al. (2013). TALEN-mediated editing of the mouse Y chromosome. Nature Biotech. 31, 530. Wang, et al. (2014). Genetic screens in human cells using the CRISPR. RNA interference (RNAi) is a mechanism that inhibits gene expression at the stage of translation or by hindering the transcription of specific genes. RNAi tar Identify which of the following are examples of reverse genetics. RNA interference gene knockout using site-directed mutagenesis mutation from wildtype allele to mutant allele DNA microarray mutation from mutant allele to wildtype allele Which of the following statements represents the definition of a reversion (reverse mutation)
Gene Knockout . Gene targeting technologies are used to modify genomes of any living organismsWhen a mutation inactivates a gene function it is called as gene knockout. Gene knockout methods are used for the identification of a specific gene function by inhibiting the function of the particular gene. Gene knockout has its application both in classical genetics and modern techniques such as. RNA silencing or RNA interference refers to a family of gene silencing effects by which gene expression is negatively regulated by non-coding RNAs such as microRNAs.RNA silencing may also be defined as sequence-specific regulation of gene expression triggered by double-stranded RNA (dsRNA). RNA silencing mechanisms are highly conserved in most eukaryotes RNAi or RNA interference is a sequence-specific method to silence genes by introducing small double-stranded RNA which mediates with nucleic acids and regulate gene expression. This can be taken as the basic difference between CRISPR and RNAi. Both the techniques, CRISPR/Cas and RNAi, are powerful tools for gene manipulations although CRISPR/Cas is certainly more superior to RNAi as it can be.
RNAi is a gene-silencing phenomenon triggered by double-stranded (ds) RNA and involves the generation of 21 to 26 nt RNA segments that guide mRNA destruction. In Caenorhabditis elegans, lin-4 and let-7 encode small temporal RNAs (stRNAs) of 22 nt that regulate stage-specific development. Here we show that inactivation of genes related to RNAi pathway genes, a homolog of Drosophila Dicer (dcr-1. In gene silencing, or RNA interference (RNAi), small interfering RNA (siRNA) or short hairpin RNA (shRNA) are used to inactivate messenger RNA for a specific gene. That effectively suppresses. RNA interference (RNAi) is a cellular process in which gene expression is reduced in a sequence specific manner following the expression of short-hairpin RNA (shRNA) within the cell. Transfection of a plasmid DNA construct containing shRNA and an antibiotic resistant gene induces the knockdown gene expression of the gene of interest and enables selection and isolation of successfully. RNA interference, or RNAi, is a process that sequence-specifically destroys mRNA, causing null or hypomorphic phenotypes.RNAi provides an excellent technology platform for gene expression and gene function studies in many different models, including Drosophila, C. elegans, and mammalian cell systems.RNAi allows researchers to fully or partially suppress the expression of a specific gene. Establishment of Functional Genomics Pipeline in Mouse Epiblast-Like Tissue by Combining Transcriptomic Analysis and Gene Knockdown/Knockin/Knockout, Using RNA Interference and CRISPR/Cas9. Nozomu Takata, Eriko Sakakura, Takeya Kasukawa, Tetsushi Sakuma, Takashi Yamamoto, and ; Yoshiki Sasa
Small RNA (sRNA)-mediated gene silencing phenomena, exemplified by RNA interference (RNAi), require a unique class of proteins called Argonautes (AGOs). An AGO protein typically forms a protein- sRNA complex that contributes to gene silencing using the loaded sRNA as a specificity determinant. Here, we show that MoAGO2, one of the three AGO genes in the fungus Pyricularia oryzae (Magnaporthe. • Gene silencing is same as gene knock down but is totally different from gene knock out. Introduction 26/9/2016 4 5. There are so many approaches for gene silencing • Gene Knockout • Gene Knockdown • Gene silencing and degradation of gene using RNA technology - Antisense RNA Technology - RNAi Technology 26/9/2016 5 Cont. 6 Recently, several systems designed to trigger RNA interference by using small hairpin RNA driven by polymerase III promoters have been described. Here, we report a lentiviral-mediated small interfering RNA delivery system that can be induced by CRE recombinase. The system consists of a lentiviral vector carrying a mouse U6 promoter that is separated from a small hairpin RNA by a random DNA. Shhh: Silencing Genes with RNA Interference TECHNICAL KNOCKOUT: A Cy3-labeled siRNA targeting B-actin was transfected into HeLa cells and protein expression was analyzed 96-hours later. Red, Cy3-labeled siRNA; Blue: DAPI-stained nuclei; Green, B-actin protein. (siRNA was prepared and labeled using Ambion's Silencer siRNA construction kit and labeling kit, respectively). RNA interference, or.
. Improved methods are needed for the knockout of individual genes in genome-scale functional screens. Wang et al. (p. , published online 12 December) and Shalem et al. (p. , published online 12 December) used the bacterial CRISPR/Cas9 system to power-screen protocols that avoid several of the pitfalls associated with small interfering RNA (siRNA) screens Genetic screening is the most powerful method through which to uncover gene function. It has been applied very successfully in lower organisms but seldom attempted in mammalian species because of their long generation time. In this study, we exploit RNA interference (RNAi) for its potential use in genetic screening in mice. We show that RNAi-induced gene knockdown can be generated through. RNA interference: from gene silencing to gene-specific therapeutics Ray K.M. Leung, Paul A. Whittaker* Novartis Institutes for Biomedical Research, Respiratory Disease Area, Wimblehurst Road, Horsham, West Sussex, RH12 5AB, United Kingdom Abstract In the past 4 years, RNA interference (RNAi) has become widely used as an experimental tool to analyse the function of mammalian genes, both in. RNA interference (RNAi) is a powerful new gene knockdown technique that permits tissue-specific, temporally controlled suppression of gene expression. It exploits a highly conserved, endogenous mechanism thought to play a role in protection against double stranded RNA (dsRNA) viruses ( 1 ) and genome-invading transposable elements ( 2 , 3 ), as well as helping preserve genome stability in the.
RNA interference (RNAi) is an innate process in which cells destroy the mRNA copy of a particular gene, blocking that gene's effects. Normally, cells use this process to silence harmful mRNAs, such as those from viruses, but once researchers learned that cells could perform RNAi, they sought to re-steer it to block whatever genes the researchers chose, and thus co-opt it as a research tool Title: RNA interference 1 Regulation of gene expression by small RNAs Garrett A. Soukup Creighton University School of Medicine Department of Biomedical Sciences 2 Objectives. Appreciate that there are two related biochemical pathways through which small RNAs can affect gene expression ; Understand how each pathway through its small RNA product (siRNA or miRNA) differently affects gene. Gene Knockout Stable Cell Lines. Our scientists have years of experience at performing gene editing with CRISPR/Cas9, from designing gRNA to transfection and single clone generation. Creative Biogene is offering a series of gene knockout cell lines developed by CRISPR/Cas9 system. These cell lines provide you with a convenient means to study. RNA interference (RNAi) is the process by which dsRNA silences gene expression, either by inducing the sequence-specific degradation of complementary mRNA or by inhibiting translation . In a wide range of organisms, double-stranded RNA triggers posttranscriptional gene silencing or RNA interference (RNAi). Genetic and biochemical investigations of the mechanisms guiding RNAi in different. Insertional mutagenesis and gene silencing are efficient tools for the determination of gene function. In contrast to gain- or loss-of-function approaches, RNA interference (RNAi)-induced gene silencing can possibly silence multigene families and homoeologous genes in polyploids. This is of great importance for functional studies in hexaploid wheat ( Triticum aestivum ), where most of the.
RNA interference is useful for studying a specific gene function through a knockout condition. This technique, otherwise known as RNAi, silences and shuts down mRNA following transcription through degradation . By eliminating gene function, RNAi yields information on what role the gene--and inherently the protein--played inside the organism. RNAi is also useful for evaluating responses to. Learn more about how BioLegend is addressing reproducibility in research, by using CRISPR/CAS9-mediated knockout/knockdown and siRNA-mediated knockdown models to validate antibody specificity. BioLegend develops and manufactures world-class, cutting-edge immunological reagents for biomedical research, offered at an outstanding value RNA interference (RNAi; post-transcriptional gene silencing) The ability of double-stranded RNA to interfere with, or suppress, the expression of a gene with a corresponding base sequence.The phenomenon occurs in many types of organisms, including plants, fungi, and animals. Double-stranded RNA, which is normally a rarity in cells, is cut into fragments by a ribonuclease enzyme (e.g. Dicer in. This mechanism can also be triggered experimentally to study gene function in organisms for which the tools for facile gene knockout are not available. RNAi-mediated gene knockdown has been used to study gene function in different honey bee developmental stages, including embryos [ 54 - 60 ], larvae [ 3 , 56 , 61 - 68 ], pupae [ 56 , 69 , 70 ], and fully developed adult honey bees [ 2 , 4. The targeted gene disruption (or knockout) approach has been nearly the only method available to inactivate a gene in mammals, until the advent of RNA interference (RNAi). RNAi induced by short double-stranded RNA (dsRNA) has gained widespread application in biological research since its discovery (7, 14, 15)
Knockdown Services RNA interference has become a widely used approach to perform gene knockdown experiments in cell cultures and more recently transgenic animals. It has developed into a routine method to assess gene function in a fast and easy manner. Since 2008, Creative Animodel's scientists have generated more than 200 RNAi models for innovative biomedical researchers. These RNAi models. RNA interference: new mechanistic and biochemical insights with application in oral cancer therapy Smaranda Buduru,1 Alina-Andreea Zimta,2 Cristina Ciocan,2 Cornelia Braicu,3 Diana Dudea,4 Alexandra Iulia Irimie,4 Ioana Berindan-Neagoe2,3,5 1Department of Prosthetics and Dental Materials, Faculty of Dental Medicine, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca.
RNA interference (RNAi) is a powerful approach to dissect gene function (Fire 2007; Mello 2007). It was originally discovered in Caenorhabditis elegans, where the observation of gene inactivation by both sense and antisense RNAs (Guo and Kemphues 1995) led to the finding of double-stranded RNA (dsRNA)-mediated gene silencing (Fire et al. 1998) Gene knockout: Gene knockout GENE KNOCK OUT TECHNOLOGY deals with existing gene by replacing it or disrupting it with an artificial piece of DNA . Knockouts are used to study the function of specific genes. The first recorded knockout mouse was created by Mario R. Capecchi , Martin Evans and Oliver Smithies in 198 Double-stranded (ds) RNA can induce sequence-specific inhibition of gene function in several organisms. However, both the mechanism and the physiological role of the interference process remain mysterious. In order to study the interference process, we have selected C. elegans mutants resistant to dsRNA-mediated interference (RNAi). Two loci, rde-1 and rde-4, are defined by mutants strongly. Use of RNA Interference with TCR Transfer to Enhance Safety and Efficiency. Nicholas Paul Casey, Jon Amund Kyte, Hiroshi Fujiwara . Pages 327-349. CRISPR/Cas9 Guide RNA Design Rules for Predicting Activity. Kasidet Hiranniramol, Yuhao Chen, Xiaowei Wang. Pages 351-364. CRISPR-Cas9 Genome Editing in Human Cell Lines with Donor Vector Made by Gibson Assembly. Nirakar Sahoo, Victoria Cuello. The main distinction between RNAi and CRISPR-Cas9 is that RNAi reduces or knocksdown gene expression at the post-transcriptional level by targeting RNA, whereas CRISPR-Cas9 is a gene-editing tool, so targets DNA to permanently alter, or knockout, gene expression. Knockdown with RNAi produces a hypomorphic phenotype in contrast to the true null knockout possible with CRISPR-Cas9. Both options.
The effectiveness of RNA interference (RNAi) is demonstrated in the lignin-degrading fungus Phanerochaete chrysosporium . The manganese-containing superoxide dismutase gene ( MnSOD1 ) was used as the target for RNAi. The plasmid constructed for gene silencing contained a transcriptional unit for hairpin RNA expression. Significantly lower MnSOD expression at both the mRNA and protein activity. gene knockouts through target gene deletion; (2) Lentiviral based CRISPR system: we established a dual gRNA lentiviral system that allows expression of two gRNAs for deleting user defined genomic DNA sequences; (3) RNA interference: transfection of small interfering RNA (siRNA) enabled repression of targeted mRNA. Discussed here are advantages and limitations of each technology and lncRNA. Specific gene silencing through RNA interference (RNAi) holds great promise as the next-generation therapeutic development platform. Previously, we have shown that branched, tripodal interfering RNA (tiRNA) structures could simultaneously trigger RNAi-mediated gene silencing of three target genes with 38 nt-long guide strands associated with Argonaute 2 Conditional Knockout Mice Model Service Provider Welcome to Creative Animodel. Menu Skip to content. Home; About Us; Search. Search for: RNAi-mediated gene knockdown Small Interference RNA Knocks down the Expression of Gene CCP22 . April 29, 2015 April 29, 2015 / creativeanimodel / Leave a comment. TGF β-Smad had wide signaling pathways involved in the regulation of various life processes. Start studying RNA Interference (Knockdown, Knockout or Knocked up). Learn vocabulary, terms, and more with flashcards, games, and other study tools
RNA interference (RNAi) is a form of post transcriptional gene regulation in which non translated double stranded RNA (dsRNA) molecules called small interfering RNA (siRNA) mediate sequence specific degradation of target messenger RNA (mRNA). RNA silencing is a novel gene regulatory mechanism that limits the transcript level by either suppressing transcription (TGS) or by activating a sequence. Abstract. RNA interference is a powerful method for inhibition of gene expression in Trypanosoma brucei(Ngo, H., Tschudi, C., Gull, K., and Ullu, E. (1998) Proc. Natl. Acad. Sci. U. S. A. 95, 14687-14692). Here we describe a vector (pZJM) for in vivo tetracycline-inducible synthesis of double-stranded RNA (dsRNA) in stably transformed cells. The dsRNA is synthesized from opposing T7 promoters CRISPR makes gene knockout easier. However, screening real knockout cells is challenging. OriGene provides gene specific CRISPR knockout kits which contain a mammalian selection marker to select edited cells. Each kit contains 2 gene-specific gRNA vectors, 1 gRNA scramble vector and one donor vector selection cassette Dicer-substrate siRNA (DsiRNA) was a useful tool for sequence-specific gene silencing. DsiRNA was proposed to have increased efficacy via RNAi gene silencing, but the molecular mechanism underlying the increased efficacy is not precise. We designed the tetra-looped DsiRNA as the tetra-looped RNAs have been reported more stable structure and increased binding efficiency with RNA and protein Mechanism of RNA interference (RNAi) 5 Figure 2. Small hairpin RNAs (shRNAs) generated using an oligonucleotide DNA sequence 8 Figure 3. Overview of the Knockout RNAi Systems procedure 15 Figure 4. shRNA oligonucleotide sequence design 20 Figure 5. Procedures provided for viral delivery of recombinant pSIREN 26 Figure 6. Restriction Map and Cloning Site of the RNAi-Ready pSIREN-RetroQ.
RNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression or translation, by neutralizing targeted mRNA molecules. Historically, RNAi was known by other names, including co-suppression, post-transcriptional gene silencing (PTGS), and quelling. The detailed stud RNA interference (RNAi) is an efficient method that can be used for this purpose. Effective gene silencing by RNAi depends on a number of important parameters, including the dynamics of gene expression and the RNA dose. Using mouse hepatoma cells, we detail some of the principal characteristics of RNAi as a tool for gene silencing, such as the RNA dose level, RNA complex exposure time, and the.
Many parallels have been drawn between the newly discovered CRISPR-Cas9 system and the RNA interference (RNAi) pathway in terms of their utility for understanding and interrogating gene function in mammalian cells. Given this similarity, the CRISPR-Cas9 field stands to benefit immensely from lessons learned during the development of RNAi technology. We examine how the history of RNAi can. Die RNA-Interferenz (kurz RNAi oder auch RNA-Silencing) ist ein natürlicher Mechanismus in den Zellen von Lebewesen mit einem Zellkern (Eukaryoten), welcher der zielgerichteten Abschaltung von Genen dient. Sie ist ein Spezialfall der Gen-Stilllegung. Die RNA-Interferenz beruht auf einer Wechselwirkung kurzer Stücke von Ribonukleinsäure (RNA) mit der Erbinformation-übertragenden mRNA unter. RNA interference (RNAi) is a powerful method for determining the role of specific genes during Drosophila embryogenesis. This protocol describes a method for RNAi in vivo using tissue-specific Gal-4 transgenes to induce dsRNA synthesis from an upstream activator sequence (UAS) vector. This vector contains the desired exonic inverted sequences representing the target gene (preferably more than. ADVERTISEMENTS: Read this article to learn about the technical considerations required in the use of RNA interference. In several respects the approaches for silencing gene expression using RNAi methods are similar to those used for antisense DNA-mediated suppression of gene expression. In principle, any cloned gene can be targeted by designing RNA oligonucleotides or RNA-expressing [
CRISPR interference (CRISPRi) is an emerging technology that exploits the catalytically inactive Cas9 (dCas9) and single guide RNA (sgRNA) to repress sequence-specific genes without the need of gene knockout, and is repurposed to rewire metabolic networks in various procaryotic cells. To employ CRISPRi for the manipulation of gene network in. RNA interference of peroxisome-related genes in C. elegans: a new model for human peroxisomal disorders OLEH I. PETRIV,1 DAVID B. PILGRIM,2 RICHARD A. RACHUBINSKI,1 AND VLADIMIR I. TITORENKO1 1Department of Cell Biology, University of Alberta, Edmonton T6G 2H7; and 2Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E RNA interference-based gene silencing of phytoene synthase impairs growth, carotenoids, and plastid phenotype in Oncidium hybrid orchid Jian-Xin Liu1, Chung-Yi Chiou2,5, Chin-Hui Shen2,4, Peng-Jen Chen2, Yao-Chung Liu2, Chin-Der Jian3, Xiao-Lan Shen1, Fu-Quan Shen1 and Kai-Wun Yeh2* Abstract Phytoene synthase (PSY) is the first rate-limiting regulatory enzyme in the carotenoid biosynthesis.