We thank Drs. Alison Heffer and Yong Lu for setting up the microinjection apparatus and sharing their invaluable knowledge and experience with insect RNAi. This work was supported by the National Institutes of Health (R01GM113230 to L.P.).

The authors have nothing to disclose.

Si bien se han desarrollado un pequeño número de sistemas de modelos sofisticados (ratones, moscas, gusanos) durante el siglo 20, el siglo 21 ha visto una ola de nuevos sistemas de los animales que se desarrollan en los laboratorios de todo el mundo. Estos nuevos sistemas permiten a los científicos para hacer frente a cuestiones comparativos y evolutivos que no pueden ser palpados utilizando sólo los sistemas modelo &quot;estándar&quot;. Este despliegue de nuevos modelos requiere el rápido de...

En 1998, Fire y Mello informaron de que el ARN de doble cadena (dsRNA) puede inducir la inhibición de la función de genes en Caenorhabditis elegans 1. Esta respuesta desencadenada por dsRNA se denomina ARN de interferencia (RNAi), y se informó como el silenciamiento de genes mediada por ARNi ser conservadas en los animales, las plantas y los hongos 2-7. En las plantas y algunos animales, las funciones de RNAi sistémica, lo que significa que el efecto se pueden propagar a otras células / tejidos en los que no se introduce directamente ARN de doble cadena (revisado en 8-10). Los científicos han hecho uso de esta respuesta ARNi celular endógeno mediante el diseño de ARN de doble cadena para apuntar genes de interés, llamando así a la baja la función de genes sin manipular directamente el genoma (revisado en 11-14). RNAi es una herramienta poderosa para los estudios funcionales debido a las siguientes ventajas. En primer lugar, incluso con un mínimo de información de la secuencia de genes, un gen puede ser objetivo utilizando RNAi. Esto es especialmente importante para studies de organismos modelo que carecen de datos genómicos o transcriptómica. En segundo lugar, en los organismos donde la respuesta RNAi es robusta sistémica, mediada por RNAi desmontables gen se puede realizar en casi cualquier etapa de desarrollo. Esta característica es muy útil para estudiar la función de genes pleiotrópicos. En tercer lugar, en algunos casos, los efectos de RNAi se propagan a las gónadas y la progenie, como que los fenotipos se observan en la descendencia 15,16. Este fenómeno, conocido como parental RNAi (pRNAi), es especialmente ventajoso para los genes que afectan el desarrollo embrionario, tan numerosos descendencia producida por un solo padre inyectado puede examinarse sin manipulación directa de los huevos. Por estas razones, pRNAi es el método de elección. Sin embargo, si pRNAi es ineficaz, por ejemplo, para los genes necesarios para la ovogénesis, entonces embrionario RNAi (eRNAi) debe ser utilizado. En cuarto lugar, RNAi puede ser utilizado para generar el equivalente de una serie alélica en que la cantidad de dsRNA entregado se puede variar en un rango para producir débil para defectos fuertes. una gradación de fenotipos Tal puede ser útil para la comprensión de la función del gen cuando el gen está implicado en un proceso complejo y / o la pérdida completa de la función es letal. En quinto lugar, la entrega de dsRNA es generalmente fácil y factible, especialmente en animales que muestran robustas respuestas RNAi sistémicos. ARN de doble cadena puede ser introducido mediante microinyección 1,5, la alimentación / ingestión 17,18, remojo, 19,20 y virus / bacterias mediada por la entrega 21,22. En sexto lugar, a diferencia de algunos métodos de focalización / edición de genes, no hay necesidad para la detección de organismos portadores de la mutación o para llevar a cabo los cruces genéticos para generar homocigotos utilizando RNAi. Por lo tanto, en comparación con muchas otras técnicas para estudiar la función de genes, RNAi es rápido, barato, y se puede aplicar para pantallas de gran escala 23-25. La amplia utilidad del ARNi proporciona medios para llevar a cabo estudios funcionales en una amplia gama de organismos, la ampliación de la gama de especies disponibles para el estudio Beyond los sistemas modelo tradicional para el que se han desarrollado herramientas genéticas. Por ejemplo, se requieren estudios que utilizan sistemas que no son modelos para dar una visión de la evolución de los genes y las redes de genes mediante la comparación de las funciones de los ortólogos de especies que representan diferentes modos de desarrollo o exhibir características morfológicas distintas 26-29. Estos tipos de estudios proporcionarán una mejor comprensión de la diversidad biológica, con repercusiones tanto para la investigación básica y aplicada. Siendo el grupo animal más grande del planeta, los insectos proporcionan una gran oportunidad para explorar los mecanismos de la diversidad subyacente. Además, los insectos son generalmente pequeños, tienen ciclos de vida cortos, alta fecundidad, y son fáciles de criar en el laboratorio. En las últimas dos décadas, el ARNi se ha aplicado con éxito en los insectos que abarca órdenes, incluyendo dípteros (moscas verdaderas) 5, Lepidoptera (mariposas y polillas) 30, coleópteros (escarabajos) 16,31, himenópteros (Sawfmentiras, avispas, hormigas y abejas) 32, hemípteros (chinches), Isoptera (termitas) 34, Blattodea (cucarachas) 35, ortópteros (grillos, saltamontes, langostas y saltamontes) 36 y Phthiraptera (piojos) 37. La aplicación exitosa de RNAi ha proporcionado datos funcionales para el estudio de los patrones en la embriogénesis temprana (eje antero-posterior 32, eje dorso-ventral 28, la segmentación 26,38), la determinación del sexo 39,40, la biosíntesis de quitina / cutícula 41, ecdisona señalización 42, el comportamiento social de 43 años, y más. Métodos de ARNi desarrollados para diferentes especies de insectos pueden ser de beneficio adicional en que es probable que sea útil para el control de plagas (revisado en 44 a 46). RNAi efectos serán de genes específicos, así como específico de la especie, siempre que las regiones no conservadas se eligen para la orientación. Para las especies de insectos beneficiosos como las abejas y gusanos de seda, dirigidos a los genes vitales para la supervivencia devirus o parásitos para controlar la infección pueden proporcionar una nueva estrategia para proteger estas especies 47,48. Dermestes maculatus (D. maculatus), nombre común ocultar escarabajo, se distribuye en todo el mundo a excepción de la Antártida. Como un insecto holometabolous, el ciclo de vida de D. maculatus incluye embrionario, larvas, pupas y adultos etapas (Figura 1). Porque se alimenta de carne, D. maculatus se utiliza en museos para esqueletizar animales muertos y entomólogos forenses se puede utilizar para estimar el tiempo de la muerte 49,50. D. maculatus se alimenta de productos de origen animal, incluyendo canales, carne seca, queso y las pupas / capullos de otros insectos y por lo tanto causa daño a los hogares, los alimentos almacenados, y la seda, el queso, la carne y las industrias de 51,52. La aplicación de RNAi en este escarabajo podría proporcionar una forma eficiente y respetuosa con el medio ambiente para reducir al mínimo su impacto económico. Nuestro laboratorio ha utilizado D. maculatus como un nuevo mOdel insectos para estudiar la segmentación 53. Además de ser susceptible a la cría de laboratorio, D. maculatus es de interés para la investigación básica, ya que es un desarrollador intermedio de gérmenes, por lo que es una especie útil para estudiar la transición entre el desarrollo a corto y largo germen. <img alt="Figura 1" src="/files/ftp_upload/54976/54976fig1.jpg" /> Figura 1: Ciclo de vida de D. maculatus. Las fotografías de D. maculatus en diferentes etapas de la vida, como se indica. El ciclo de vida de huevo a adulto dura tres semanas a 30 ° C, pero ya a temperaturas más bajas. (A, F), los embriones recién puestos son de color blanco a amarillo claro y ovalados, de aproximadamente 1,5 mm de longitud. Embriogénesis toma ~ 55 horas a 30 ° C. (B, C y G) Las larvas tienen rayas pigmentadas oscuras y están cubiertas de pelos. Las larvas pasan por varios estadios en función del entorno y su duración puede extenderse hasta más de 1 cm. (D, H) </strong&gt; pupas jóvenes son de color amarillo claro. La pupación tiene ~ 5 - 7 días a 30 ° C. (E, I) Poco después de la eclosión, pigmentación oscura aparece sobre el cuerpo del escarabajo adulto. Los adultos pueden vivir hasta varios meses y una hembra puede poner cientos de embriones durante su vida. <a href="http://ecsource.jove.com/files/ftp_upload/54976/54976fig1large.jpg" target="_blank">Haga clic aquí para ver una versión más grande de esta figura.</a> Anteriormente, hemos demostrado que el ARNi es eficaz en el derribo de genes en función de D. maculatus 53. Aquí nuestra experiencia crianza de colonias D. maculatus en el laboratorio es compartido junto con los protocolos de paso a paso, tanto para los padres embrionario y ARNi puesta en marcha, la inyección, la atención post-inyección, y el análisis fenotípico. Los métodos de derribo y análisis de genes mediada por dsRNA introducidos aquí no sólo proporcionar información detallada para abordar cuestiones de D. maculatus, sino que también tienen importancia potencial for la aplicación de RNAi en otros no modelo escarabajo / especies de insectos.

<table><tbody><tr><td>&lt;em&gt;Dermestes maculatus&lt;/em&gt; live beetles</td><td>Our lab or Carolina Biological Supply</td><td>#144168</td><td>Our lab strain was verified by COI barcoding; strain variation from Carolina cannot be ruled out</td></tr><tr><td>Wet cat food</td><td>Fancy Feast</td><td></td><td>Chunks of meat with gravy. Can buy at most pet food and grocery stores</td></tr><tr><td>Dry dog food</td><td>Purina Puppy Chow</td><td></td><td>Can buy at most pet food and grocery stores</td></tr><tr><td>Insect cage (size medium, 30.5 x 19 x 20.3 cm)</td><td>Exo Terra</td><td>PT2260</td><td>For colony maintenance. Can use larger cage if needed</td></tr><tr><td>Insect cage (size mini, 17.8 x 10.2 x 12.7 cm)</td><td>Exo Terra</td><td>PT2250</td><td>For embryo collection</td></tr><tr><td>Petri dish</td><td>VWR</td><td>89038-968</td><td></td></tr><tr><td>Cotton ball</td><td>Fisher</td><td>22-456-883</td><td></td></tr><tr><td>Megascript T7 transcription kit</td><td>Fisher</td><td>AM1334</td><td>For 40 reactions</td></tr><tr><td>Pneumatic pump</td><td>WPI</td><td>PV830</td><td></td></tr><tr><td>Capillary holder</td><td>WPI</td><td></td><td></td></tr><tr><td>Micromanipulator</td><td>NARISHIGE</td><td>MN-151</td><td></td></tr><tr><td>Black filter paper (90&amp;nbsp;mm)</td><td>VWR</td><td>28342-010</td><td></td></tr><tr><td>Food coloring (green)</td><td>McCormick</td><td></td><td></td></tr><tr><td>Borosilicate glass capillary</td><td>Hilgenberg</td><td>1406119</td><td></td></tr><tr><td>Needle puller (micropipette puller)</td><td>Sutter Instrument Co.</td><td>P-97</td><td></td></tr><tr><td>Microscope glass slide</td><td>WorldWide Life Sciences Division</td><td>41351157</td><td></td></tr><tr><td>Sealing film (Parafilm M)</td><td>Fisher</td><td>13-374-12</td><td></td></tr><tr><td>Model 801 Syringe (10&amp;nbsp;&amp;micro;l)</td><td>Hamilton</td><td>7642-01</td><td></td></tr><tr><td>Needle (32-gauge)&amp;nbsp;</td><td>Hamilton</td><td>7762-05</td><td></td></tr><tr><td>Fixation Solution (Pampel&#039;s)</td><td>BioQuip Products, Inc.</td><td>1184C</td><td>Toxic, needs to be handled in fume hood</td></tr><tr><td>Forcep (DUMONT #5)</td><td>Fine Science Tools</td><td>11252-30</td><td></td></tr><tr><td>Cover slip (24 x 50 mm, No. 1.5)</td><td>Globe Scientific</td><td>1415-15</td><td></td></tr><tr><td>Eppendorf Femtotips Microloader pipette tip</td><td>Fisher</td><td>E5242956003</td><td></td></tr><tr><td>Dissecting microscopy for embryo injection</td><td>Leica</td><td>M420</td><td></td></tr><tr><td>Dissecting microscopy for larval phenotypic visualization</td><td>Zeiss</td><td>SteREO Discover. V12</td><td></td></tr><tr><td>DIC microscopy</td><td>Zeiss</td><td>AXIO Imager. M1</td><td></td></tr></tbody></table>

rearing and double-stranded rna-mediated gene knockdown in the hide beetle, dermestes maculatus

Advances in genomics have raised the possibility of probing biodiversity at an unprecedented scale. However, sequence alone will not be informative without tools to study gene function. The development and sharing of detailed protocols for the establishment of new model systems in laboratories, and for tools to carry out functional studies, is thus crucial for leveraging the power of genomics. Coleoptera (beetles) are the largest clade of insects and occupy virtually all types of habitats on the planet. In addition to providing ideal models for fundamental research, studies of beetles can have impacts on pest control as they are often pests of households, agriculture, and food industries. Detailed protocols for rearing and maintenance of D. maculatus laboratory colonies and for carrying out dsRNA-mediated interference in D. maculatus are presented. Both embryonic and parental RNAi procedures-including apparatus set up, preparation, injection, and post-injection recovery-are described. Methods are also presented for analyzing embryonic phenotypes, including viability, patterning defects in hatched larvae, and cuticle preparations for unhatched larvae. These assays, together with in situ hybridization and immunostaining for molecular markers, make D. maculatus an accessible model system for basic and applied research. They further provide useful information for establishing procedures in other emerging insect model systems.

Laboratorio de los autores ha utilizado la tecnología de ARNi para estudiar la evolución funcional de los genes que regulan la segmentación en los insectos 53,55. Mientras que todos los insectos son segmentados, los genes que regulan este proceso parecen haber divergido durante las radiaciones de insectos 26,38,56-63. Cribados genéticos en Drosophila identificaron un conjunto de nueve pares de reglas de segmentación de los genes que son responsables de...

Watch this Scientific Journal Video about Rearing and Double-stranded RNA-mediated Gene Knockdown in the Hide Beetle, Dermestes maculatus at JoVE.com

Rearing and Double-stranded RNA-mediated Gene Knockdown in the Hide Beetle, Dermestes maculatus

A continuación, presentamos los protocolos para la crianza de un escarabajo intermedia de gérmenes, Dermestes maculatus (D. maculatus) en el laboratorio. También compartimos protocolos para RNAi embrionario y de los padres y los métodos para el análisis de los fenotipos de embriones para estudiar la función de genes en esta especie.

La cría y el doble-stranded RNA mediada gen desmontables en el Hide Escarabajo,<em&gt; Dermestes maculatus</em

Advances in genomics have raised the possibility of probing biodiversity at an unprecedented scale. However, sequence alone will not be informative ...

rearing-double-stranded-rna-mediated-gene-knockdown-hide-beetle

Research

JoVE Journal

Genetics

Rearing and Double-stranded RNA-mediated Gene Knockdown in the Hide Beetle, Dermestes maculatus

10.5K vistas.  University of Maryland.  A continuación, presentamos los protocolos para la crianza de un escarabajo intermedia de gérmenes, Dermestes maculatus (D. maculatus) en el laboratorio. También compartimos protocolos para RNAi embrionario y de los padres y los métodos para el análisis de los fenotipos de embriones para estudiar la función de genes en esta especie. 

Video: Rearing and Double-stranded RNA-mediated Gene Knockdown in the Hide Beetle, Dermestes maculatus

RNA Interference in Aquatic Beetles as a Powerful Tool for Manipulating Gene Expression at Specific Developmental Time Points

RNA interference (RNAi) remains a powerful technique that allows for the targeted reduction of gene expression through mRNA degradation. This technique is applicable to a wide variety of organisms and is highly efficient in the species-rich order Coleoptera (beetles). Here, we summarize the necessary steps for developing this technique in a novel organism and illustrate its application to the different developmental stages of the aquatic diving beetle Thermonectus marmoratus. Target gene sequences can be obtained cost-effectively through the assembly of transcriptomes against a close relative with known genomics or de novo. Candidate gene cloning utilizes a specific cloning vector (the pCR4-TOPO plasmid), which allows the synthesis of double-stranded RNA (dsRNA) for any gene with the use of a single common primer. The synthesized dsRNA can be injected into either embryos for early developmental processes or larvae for later developmental processes. We then illustrate how RNAi can be injected into aquatic larvae using immobilization in agarose. To demonstrate the technique, we provide several examples of RNAi experiments, generating specific knockdowns with predicted phenotypes. Specifically, RNAi for the tanning gene laccase2 leads to cuticle lightening in both larvae and adults, and RNAi for the eye pigmentation gene white produces a lightening/lack of pigmentation in eye tubes. In addition, the knockdown of a key lens protein leads to larvae with optical deficiencies and a reduced ability to hunt prey. Combined, these results exemplify the power of RNAi as a tool for investigating both morphological patterning and behavioral traits in organisms with only transcriptomic databases.

RNA interference is a widely applicable, powerful technique for manipulating gene expression at specific developmental stages. Here, we describe the necessary steps for implementing this technique in the aquatic diving beetle Thermonectus marmoratus, from the acquisition of gene sequences to the knockdown of genes that affect structure or behavior.

Interferencia de ARN en los escarabajos acuáticos como una poderosa herramienta para manipular la expresión génica en puntos de tiempo de desarrollo específicos

RNA interference (RNAi) remains a powerful technique that allows for the targeted reduction of gene expression through mRNA degradation. This technique is ...

Investigación

Medio ambiente

RNAi-mediated Double Gene Knockdown and Gustatory Perception Measurement in Honey Bees (Apis mellifera)

This video demonstrates novel techniques of RNA interference (RNAi) which downregulate two genes simultaneously in honey bees using double-stranded RNA (dsRNA) injections. It also presents a protocol of proboscis extension response (PER) assay for measuring gustatory perception.	
	RNAi-mediated gene knockdown is an effective technique downregulating target gene expression. This technique is usually used for single gene manipulation, but it has limitations to detect interactions and joint effects between genes. In the first part of this video, we present two strategies to simultaneously knock down two genes (called double gene knockdown). We show both strategies are able to effectively suppress two genes, vitellogenin (vg) and ultraspiracle (usp), which are in a regulatory feedback loop. This double gene knockdown approach can be used to dissect interrelationships between genes and can be readily applied in different insect species.	
	The second part of this video is a demonstration of proboscis extension response (PER) assay in honey bees after the treatment of double gene knockdown. The PER assay is a standard test for measuring gustatory perception in honey bees, which is a key predictor for how fast a honey bee's behavioral maturation is. Greater gustatory perception of nest bees indicates increased behavioral development which is often associated with an earlier age at onset of foraging and foraging specialization in pollen. In addition, PER assay can be applied to identify metabolic states of satiation or hunger in honey bees. Finally, PER assay combined with pairing different odor stimuli for conditioning the bees is also widely used for learning and memory studies in honey bees.

RNAi-mediated Double Gene Knockdown and Gustatory Perception Measurement in Honey Bees Apis mellifera

In this protocol, we describe two strategies that simultaneously suppress two genes (double gene knockdown) in honey bees. Then we present how to use the proboscis extension response (PER) assay to study the effect of double gene knockdown on honey bee gustatory perception.

RNAi mediada Doble derribo Gene y medición percepción gustativa de las abejas (<em&gt; Apis mellifera</em&gt;)

This video demonstrates novel techniques of RNA  interference (RNAi) which downregulate two genes simultaneously in honey bees  using double-stranded RNA ...

Neurociencias

Electroporation-mediated RNA Interference Method in Odonata

Dragonflies and damselflies (order Odonata) represent one of the most ancestral insects with metamorphosis, in which they change their habitat, morphology, and behavior drastically from aquatic larvae to terrestrial/aerial adults without pupal stage. Odonata adults have a well-developed color vision and show a remarkable diversity in body colors and patterns across sexes, stages, and species. While many ecological and behavioral studies on Odonata have been conducted, molecular genetic studies have been scarce mainly due to the difficulty in applying gene functional analysis to Odonata. For instance, RNA interference (RNAi) is less effective in the Odonata, as reported in the Lepidoptera. To overcome this problem, we successfully established an RNAi method combined with in vivo electroporation. Here we provide a detailed protocol including a video of the electroporation-mediated RNAi method as follows: preparation of larvae, species identification, preparation of dsRNA/siRNA solution and injection needles, ice-cold anesthesia of larvae, dsRNA/siRNA injection, in vivo electroporation, and individual rearing until adult emergence. The electroporation-mediated RNAi method is applicable to both damselflies (suborder Zygoptera) and dragonflies (suborder Anisoptera). In this protocol, we present the methods for the blue-tailed damselfly Ischnura senegalensis (Coenagrionidae) as an example of damselfly species and the pied skimmer dragonfly Pseudothemis zonata (Libellulidae) as another example of dragonfly species. As representative examples, we show the results of RNAi targeting the melanin synthesis gene multicopper oxidase 2. This RNAi method will facilitate understanding of various gene functions involved in metamorphosis, morphogenesis, color pattern formation, and other biological features of Odonata. Moreover, this protocol may be generally applicable to non-model organisms in which RNAi is less effective in gene suppression due to the inefficiency and low penetrance.

We provide a detailed protocol for electroporation-mediated RNA interference in insects of the order Odonata (dragonflies and damselflies) using the blue-tailed damselfly (Ischnura senegalensis: Coenagironidae: Zygoptera) and the pied skimmer dragonfly (Pseudothemis zonata: Libellulidae: Anisoptera).

Método de interferencia de ARN mediado por electroporación en Odonata

Dragonflies and damselflies (order Odonata) represent one of the most ancestral insects with metamorphosis, in which they change their habitat, ...

Biología del Desarrollo

Applications of RNA Interference in American Cockroach

Cockroaches, a sanitary pest, are essential species in insect developmental and metamorphic studies due to their easy feeding and hemimetabolous characteristics. Altogether with well-annotated genome sequences, these advantages have made American cockroach, Periplaneta americana, an important hemimetabolous insect model. Limited by the shortage of knockout strategy, effective RNA interference (RNAi)-based gene knockdown becomes an indispensable technique in functional gene research of P. americana. The present protocol describes the RNAi operation techniques in P. americana. The protocol includes (1) selection of the P. americana at proper developmental stages, (2) preparation for the injection setting, (3) dsRNA injection, and (4) gene knockdown efficiency detection. RNAi is a powerful reverse genetic tool in P. americana. The majority of P. americana tissues are sensitive to extracellular dsRNA. Its simplicity allows researchers to quickly obtain dysfunctional phenotypes under one or multiple targeting dsRNA injections, enabling researchers to better use the P. americana for developmental and metamorphic studies.

The present protocol describes step-by-step guidelines for the RNAi operation techniques in P. americana.

Aplicaciones de la interferencia de ARN en cucarachas americanas

Cockroaches, a sanitary pest, are essential species in insect developmental and metamorphic studies due to their easy feeding and hemimetabolous ...

RNAi Interference by dsRNA Injection into Drosophila Embryos

Genetic screening is one of the most powerful methods available for gaining insights into complex biological process 1. Over the years many improvements and tools for genetic manipulation have become available in Drosophila 2. Soon after the initial discovery by Frie and Mello 3 that double stranded RNA can be used to knockdown the activity of individual genes in Caenorhabditis elegans, RNA interference (RNAi) was shown to provide a powerful reverse genetic approach to analyze gene functions in Drosophila organ development 4, 5.
Many organs, including lung, kidney, liver, and vascular system, are composed of branched tubular networks that transport vital fluids or gases 6, 7. The analysis of Drosophila tracheal formation provides an excellent model system to study the morphogenesis of other tubular organs 8. The Berkeley Drosophila genome project has revealed hundreds of genes that are expressed in the tracheal system. To study the molecular and cellular mechanism of tube formation, the challenge is to understand the roles of these genes in tracheal development. Here, we described a detailed method of dsRNA injection into Drosophila embryo to knockdown individual gene expression. We successfully knocked down endogenous dysfusion(dys) gene expression by dsRNA injection. Dys is a bHLH-PAS protein expressed in tracheal fusion cells, and it is required for tracheal branch fusion 9, 10. dys-RNAi completely eliminated dys expression and resulted in tracheal fusion defect. This relatively simple method provides a tool to identify genes requried for tissure and organ development in Drosophila.

RNAi Interference by dsRNA Injection into Drosophila Embryos

RNA interference has been proven very effective to analyze gene function in Drosophila tracheal development. A detailed protocol used by Jiang lab to inject dsRNA into fly embryos to knockdown gene expression is illustrated. This technique has the potential for screening genes required for tissue and organ development in Drosophila.

RNAi interferencia por inyección de dsRNA en Drosophila Los embriones

Genetic screening is one of the most powerful methods available for gaining insights into complex biological process 1. Over the years many improvements ...

Biología

RNAi Mediated Gene Knockdown and Transgenesis by Microinjection in the Necromenic Nematode Pristionchus pacificus

Although it is increasingly affordable for emerging model organisms to obtain completely sequenced genomes, further in-depth gene function and expression analyses by RNA interference and stable transgenesis remain limited in many species due to the particular anatomy and molecular cellular biology of the organism. For example, outside of the crown group Caenorhabditis that includes Caenorhabditis elegans3, stably transmitted transgenic lines in non-Caenorhabditis species have not been reported in this specious phylum (Nematoda), with the exception of Strongyloides stercoralis4 and Pristionchus pacificus5. To facilitate the expanding role of P. pacificus in the study of development, evolution, and behavior6-7, we describe here the current methods to use microinjection for making transgenic animals and gene knock down by RNAi. Like the gonads of C. elegans and most other nematodes, the gonads of P. pacificus is syncitial and capable of incorporating DNA and RNA into the oocytes when delivered by direct microinjection. Unlike C. elegans however, stable transgene inheritance and somatic expression in P. pacificus requires the addition of self genomic DNA digested with endonucleases complementary to the ends of target transgenes and coinjection markers5. The addition of carrier genomic DNA is similar to the requirement for transgene expression in Strongyloides stercoralis4 and in the germ cells of C. elegans. However, it is not clear if the specific requirement for the animals' own genomic DNA is because P. pacificus soma is very efficient at silencing non-complex multi-copy genes or that extrachromosomal arrays in P. pacificus require genomic sequences for proper kinetochore assembly during mitosis. The ventral migration of the two-armed (didelphic) gonads in hermaphrodites further complicates the ability to inject both gonads in individual worms8. We also demonstrate the use of microinjection to knockdown a dominant mutant (roller,tu92) by injecting double-stranded RNA (dsRNA) into the gonads to obtain non-rolling F1 progeny. Unlike C. elegans, but like most other nematodes, P. pacificus PS312 is not receptive to systemic RNAi via feeding and soaking and therefore dsRNA must be administered by microinjection into the syncitial gonads. In this current study, we hope to describe the microinjection process needed to transform a Ppa-egl-4 promoter::GFP fusion reporter and knockdown a dominant roller prl-1 (tu92) mutant in a visually informative protocol.

RNAi Mediated Gene Knockdown and Transgenesis by Microinjection in the Necromenic Nematode Pristionchus pacificus

In model organisms, transgenesis can manipulate gene functions while RNAi can knockdown specific mRNA transcripts 1-2. This protocol aims to illustrate the techniques needed to introduce stably transmitted DNA and transient double stranded RNA into the necromenic nematode Pristionchus pacificus for studies in evolutionary, developmental, and behavioral biology.

RNAi mediada por derribo de genes y transgénesis por microinyección en el nematodo Necromenic Pristionchus pacificus</em

Although it is increasingly affordable for emerging model organisms to obtain completely sequenced genomes, further in-depth gene function and expression ...

Large-scale Gene Knockdown in C. elegans Using dsRNA Feeding Libraries to Generate Robust Loss-of-function Phenotypes

RNA interference by feeding worms bacteria expressing dsRNAs has been a useful tool to assess gene function in C. elegans. While this strategy works well when a small number of genes are targeted for knockdown, large scale feeding screens show variable knockdown efficiencies, which limits their utility. We have deconstructed previously published RNAi knockdown protocols and found that the primary source of the reduced knockdown can be attributed to the loss of dsRNA-encoding plasmids from the bacteria fed to the animals. Based on these observations, we have developed a dsRNA feeding protocol that greatly reduces or eliminates plasmid loss to achieve efficient, high throughput knockdown. We demonstrate that this protocol will produce robust, reproducible knock down of C. elegans genes in multiple tissue types, including neurons, and will permit efficient knockdown in large scale screens. This protocol uses a commercially available dsRNA feeding library and describes all steps needed to duplicate the library and perform dsRNA screens. The protocol does not require the use of any sophisticated equipment, and can therefore be performed by any C. elegans lab.

Large-scale Gene Knockdown in C. elegans Using dsRNA Feeding Libraries to Generate Robust Loss-of-function Phenotypes

While dsRNA feeding in C. elegans is a powerful tool to assess gene function, current protocols for large scale feeding screens result in variable knockdown efficiencies. We describe an improved protocol for performing large scale RNAi feeding screens that results in highly efficacious and reproducible knockdown of gene expression.

Derribo Gene a gran escala en<em&gt; C. elegans</em&gt; Utilizar bibliotecas de alimentación de dsRNA para generar sólidas fenotipos de pérdida de función

RNA interference by feeding worms bacteria expressing dsRNAs has been a useful tool to assess gene function in C. elegans. While this strategy works well ...

Larval RNA Interference in the Red Flour Beetle, Tribolium castaneum

The red flour beetle, Tribolium&#160;castaneum, offers a repertoire of experimental tools for genetic and developmental studies, including a fully annotated genome sequence, transposon-based transgenesis, and effective RNA interference (RNAi). Among these advantages, RNAi-based gene knockdown techniques are at the core of Tribolium research. T. castaneum show a robust systemic RNAi response, making it possible to perform RNAi at any life stage by simply injecting double-stranded RNA (dsRNA) into the beetle&#8217;s body cavity.
In this report, we provide an overview of our larval RNAi technique in T. castaneum. The protocol includes (i) isolation of the proper stage of T. castaneum larvae for injection, (ii) preparation for the injection setting, and (iii) dsRNA injection. Larval RNAi is a simple, but powerful technique that provides us with quick access to loss-of-function phenotypes, including multiple gene knockdown phenotypes as well as a series of hypomorphic phenotypes. Since virtually all T. castaneum tissues are susceptible to extracellular dsRNA, the larval RNAi technique allows researchers to study a wide variety of tissues in diverse contexts, including the genetic basis of organismal responses to the outside environment. In addition, the simplicity of this technique stimulates more student involvement in research, making T. castaneum an ideal genetic system for use in a classroom setting.

Larval RNA Interference in the Red Flour Beetle, Tribolium castaneum

RNA interference (RNAi)-based gene knockdown techniques are at the core of Tribolium research. Here, we provide an overview of our larval RNAi technique in Tribolium castaneum. Larval RNAi is a simple, but powerful technique that provides quick access to loss-of-function phenotypes, allowing researchers to study gene functions in diverse contexts.

La interferencia de ARN de las larvas en la Red Escarabajo de Harina,<em&gt; Tribolium castaneum</em

The red flour beetle, Tribolium&#160;castaneum, offers a repertoire of experimental tools for genetic and developmental studies, including a fully ...

Chitosan/Interfering RNA Nanoparticle Mediated Gene Silencing in Disease Vector Mosquito Larvae

Vector mosquitoes inflict more human suffering than any other organism&#8212;and kill more than one million people each year. The mosquito genome projects facilitated research in new facets of mosquito biology, including functional genetic studies in the primary African malaria vector Anopheles gambiae and the dengue and yellow fever vector Aedes aegypti. RNA interference- (RNAi-) mediated gene silencing has been used to target genes of interest in both of these disease vector mosquito species. Here, we describe a procedure for preparation of chitosan/interfering RNA nanoparticles that are combined with food and ingested by larvae. This technically straightforward, high-throughput, and relatively inexpensive methodology, which is compatible with long double stranded RNA (dsRNA) or small interfering RNA (siRNA) molecules, has been used for the successful knockdown of a number of different genes in A. gambiae and A. aegypti larvae. Following larval feedings, knockdown, which is verified through qRT-PCR or in situ hybridization, can persist at least through the late pupal stage. This methodology may be applicable to a wide variety of mosquito and other insect species, including agricultural pests, as well as other non-model organisms. In addition to its utility in the research laboratory, in the future, chitosan, an inexpensive, non-toxic and biodegradable polymer, could potentially be utilized in the field.

Here we describe a procedure for inhibiting gene function in disease vector mosquitoes through the use of chitosan/interfering RNA nanoparticles that are ingested by larvae.

El quitosano / ARN de interferencia mediada por nanopartículas silenciamiento génico en la enfermedad vectorial larvas de mosquitos

Vector mosquitoes inflict more human suffering than any other organism&#8212;and kill more than one million people each year. The mosquito genome projects ...

RNAi Trigger Delivery into Anopheles gambiae Pupae

RNA interference (RNAi), a naturally occurring phenomenon in eukaryotic organisms, is an extremely valuable tool that can be utilized in the laboratory for functional genomic studies. The ability to knockdown individual genes selectively via this reverse genetic technique has allowed many researchers to rapidly uncover the biological roles of numerous genes within many organisms, by evaluation of loss-of-function phenotypes. In the major human malaria vector Anopheles gambiae, the predominant method used to reduce the function of targeted genes involves injection of double-stranded (dsRNA) into the hemocoel of the adult mosquito. While this method has been successful, gene knockdown in adults excludes the functional assessment of genes that are expressed and potentially play roles during pre-adult stages, as well as genes that are expressed in limited numbers of cells in adult mosquitoes. We describe a method for the injection of Serine Protease Inhibitor 2 (SRPN2) dsRNA during the early pupal stage and validate SRPN2 protein knockdown by observing decreased target protein levels and the formation of melanotic pseudo-tumors in SRPN2 knockdown adult mosquitoes. This evident phenotype has been described previously for adult stage knockdown of SRPN2 function, and we have recapitulated this adult phenotype by SRPN2 knockdown initiated during pupal development. When used in conjunction with a dye-labeled dsRNA solution, this technique enables easy visualization by simple light microscopy of injection quality and distribution of dsRNA in the hemocoel.

RNAi Trigger Delivery into Anopheles gambiae Pupae

RNA interference (RNAi) is an extremely valuable tool for uncovering gene function. However, the ability to target genes using RNAi during pre-adult stages is limited in the major human malaria vector Anopheles gambiae. We describe an RNAi protocol to reduce gene function via direct injection during pupal development.

RNAi gatillo en la entrega<em&gt; Anopheles gambiae</em&gt; Las pupas

RNA interference (RNAi), a naturally occurring phenomenon in eukaryotic organisms, is an extremely valuable tool that can be utilized in the laboratory ...

La cría y el doble-stranded RNA mediada gen desmontables en el Hide Escarabajo,

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