We thank Reine Protacio for helpful comments during the preparation of this manuscript. We express our gratitude to the National Science Foundation (grants nos. 1243680 and 1613754) and the Hendrix College Odyssey Program for funding support.

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The authors declare that they have no competing financial interests.

O nível elevado de homologia de sequências entre os dois genes não alélicos que codificam para cada uma das quatro proteínas histona de núcleo em células haplóides de S. cerevisiae pode representar um desafio para os investigadores que desejam atingir especificamente um dos dois genes para a mutagénese. Anteriormente descreveu metodologias de mutagénese de levedura, incluindo a Delitto Perfetto, genómico de mutagénese específica do local (SSG), e métodos de substituição alelo baseada em...

Os quatro proteínas histonas centrais H2A, H2B, H3, H4 e desempenham papéis centrais na compactação, organização e função dos cromossomas eucarióticos. Dois conjuntos de cada uma destas histonas formar o octâmero da histona, um carretel molecular que dirige o invólucro de ~ 147 pares de bases de ADN em torno de si, resultando na formação de um nucleossoma 1. Nucleossomas são agentes activos numa variedade de processos à base de cromossomas, tais como a regulação da transcrição de genes e a formação de eucromatina e heterocromatina entre cromossomas, e, como tal, têm sido o foco de intensa investigação ao longo de várias décadas passadas. Um número de mecanismos têm sido descritos por nucleossomas que podem ser manipulados em formas que podem facilitar a execução dos processos específicos - estes mecanismos de modificação pós-tradução incluem os resíduos de histonas, remodelar nucleossoma dependente de ATP, e reorganização nucleossoma ATP-independentee montagem / desmontagem 2, 3. A levedura de germinação Saccharomyces cerevisiae é um organismo particularmente poderoso modelo para a compreensão da função da histona em eucariotas. Isto pode ser em grande parte atribuído ao elevado grau de conservação evolutiva das proteínas histona eukarya todo o domínio e a receptividade de levedura para uma variedade de genética e bioquímica experimental aproxima 4. abordagens Reverse-genéticos nas leveduras têm sido amplamente utilizada para estudar os efeitos de mutações específicas de histona sobre vários aspectos da biologia da cromatina. Para estes tipos de experiências é frequentemente preferível a utilização de células em que as histonas mutantes são expressos a partir de loci genómico nativo, como a expressão a partir de plasmídeos autónomos podem levar a níveis anormais intracelular de proteínas histona (devido a diferentes números de plasmídeos em células) e alteração concomitante da cromatina enam-, que em última instância pode confundir a interpretação dos resultados. Aqui, nós descrevemos uma técnica baseada em PCR que permite a mutagénese direccionada de genes de histonas nas suas localizações genómicas nativas, que não requerem um passo de clonagem e resulta na produção da mutação (ões) desejada, sem sequências de ADN exógeno que sobram no genoma. Esta técnica tira proveito do sistema de recombinação homóloga eficiente em levedura e tem várias características em comum com outras técnicas semelhantes desenvolvidas por outros grupos - mais notavelmente o Delitto Perfetto, genômica mutagénese específica (SSG), e alelo à base de PCR clonagem-livre métodos de reposição de 5, 6, 7. No entanto, a técnica que descrevem tem um aspecto que o torna particularmente adequado para a mutagénese de genes de histonas. Em células de levedura haplóides, cada um dos quatro histonas nucleares é codificada por dois não-Agenes llelic e altamente homólogas: por exemplo, histona H3 é codificado pelos genes HHT1 e HHT2, e as grelhas de leitura abertas (ORFs) dos dois genes são mais de 90% idênticos na sequência. Este elevado grau de homologia pode complicar experiências concebidas para visar especificamente um dos dois genes codificadores de histonas para mutagénese. Considerando que os métodos acima mencionados exigem frequentemente a utilização de, pelo menos, algumas sequências dentro da ORF do gene alvo para dirigir recombinação homóloga, a técnica aqui descrita faz uso das sequências que flanqueiam as ORFs dos genes de histonas (que partilhem menos homologia de sequência) para o passo de recombinação, aumentando assim a probabilidade de sucesso de mutagénese direccionamento ao local desejado. Além disso, as regiões homólogas que impulsionam a recombinação pode ser muito extensa, contribuindo para a eficiente recombinação homóloga alvo.

<table><tbody><tr><td>1 kb DNA Ladder (DNA standards)</td><td>New England BioLabs</td><td>N3232L</td><td></td></tr><tr><td>Agarose&amp;nbsp;</td><td>Sigma</td><td>A5093-100G</td><td></td></tr><tr><td>Boric Acid</td><td>Sigma</td><td>B0394-500G</td><td></td></tr><tr><td>dNTP mix (10 mM each)</td><td>ThermoFisher Scientific</td><td>R0192</td><td></td></tr><tr><td>EDTA solution (0.5 M, pH 8.0)</td><td>AmericanBio</td><td>AB00502-01000</td><td></td></tr><tr><td>Ethanol (200 Proof)</td><td>Fisher Scientific</td><td>16-100-824</td><td></td></tr><tr><td>Ethylenediaminetetraacetic acid disodium salt dihydrate (EDTA)</td><td>Sigma</td><td>E4884-500G</td><td></td></tr><tr><td>Lithium acetate dihydrate</td><td>Sigma</td><td>L6883-250G</td><td></td></tr><tr><td>MyCycler Thermal Cycler</td><td>BioRad</td><td>170-9703</td><td></td></tr><tr><td>Poly(ethylene glycol) (PEG)</td><td>Sigma</td><td>P3640-1KG</td><td></td></tr><tr><td>PrimeSTAR HS DNA Polymerase (high fidelity DNA polymerase)&amp;nbsp; and 5x buffer</td><td>Fisher Scientific</td><td>50-443-960</td><td></td></tr><tr><td>Salmon sperm DNA solution</td><td>ThermoFisher Scientific</td><td>15632-011</td><td></td></tr><tr><td>Sigma 7-9 (Tris base, powder form)</td><td>Sigma</td><td>T1378-1KG</td><td></td></tr><tr><td>Sodium acetate trihydrate</td><td>Sigma</td><td>236500-500G</td><td></td></tr><tr><td>Supra Sieve GPG Agarose (low metling temperature agarose)</td><td>AmericanBio</td><td>AB00985-00100</td><td></td></tr><tr><td>Taq Polymerase and 10x Buffer</td><td>New England BioLabs</td><td>M0273X</td><td></td></tr><tr><td>Toothpicks</td><td>Fisher Scientific</td><td>S67859</td><td></td></tr><tr><td>Tris-HCl (1 M, pH 8.0)</td><td>AmericanBio</td><td>AB14043-01000</td><td></td></tr><tr><td>a-D(+)-Glucose</td><td>Fisher Scientific</td><td>AC170080025</td><td>for yeast media</td></tr><tr><td>Agar</td><td>Fisher Scientific</td><td>DF0140-01-0</td><td>for yeast media</td></tr><tr><td>Peptone</td><td>Fisher Scientific</td><td>DF0118-07-2</td><td>for YPD medium</td></tr><tr><td>Yeast Extract</td><td>Fisher Scientific</td><td>DF0127-17-9</td><td>for YPD medium</td></tr><tr><td>4-aminobenzoic acid</td><td>Sigma</td><td>A9878-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>Adenine</td><td>Sigma</td><td>A8626-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>Glycine hydrochloride</td><td>Sigma</td><td>G2879-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>L-Alanine</td><td>Sigma</td><td>A7627-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>L-Arginine monohydrochloride</td><td>Sigma</td><td>A5131-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>L-Asparagine monohydrate</td><td>Sigma</td><td>A8381-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>L-Aspartic acid sodium salt monohydrate</td><td>Sigma</td><td>A6683-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>L-Cysteine hydrochloride monohydrate</td><td>Sigma</td><td>C7880-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>L-Glutamic acid hydrochloride</td><td>Sigma</td><td>G2128-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>L-Glutamine</td><td>Sigma</td><td>G3126-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>L-Histidine monohydrochloride monohydrate</td><td>Sigma</td><td>H8125-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>L-Isoleucine</td><td>Sigma</td><td>I2752-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>L-Leucine</td><td>Sigma</td><td>L8000-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>L-Lysine monohydrochloride</td><td>Sigma</td><td>L5626-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>L-Methionine</td><td>Sigma</td><td>M9625-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>L-Phenylalanine</td><td>Sigma</td><td>P2126-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>L-Proline</td><td>Sigma</td><td>P0380-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>L-Serine</td><td>Sigma</td><td>S4500-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>L-Threonine</td><td>Sigma</td><td>T8625-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>L-Tryptophan</td><td>Sigma</td><td>T0254-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>L-Tyrosine</td><td>Sigma</td><td>T3754-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>L-Valine</td><td>Sigma</td><td>V0500-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>myo-Inositol</td><td>Sigma</td><td>I5125-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>Uracil</td><td>Sigma</td><td>U0750-100G</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>Ammonium Sulfate</td><td>Fisher Scientific</td><td>A702-500</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>Yeast Nitrogen Base</td><td>Fisher Scientific</td><td>DF0919-07-3</td><td>for complete minimal dropout medium&amp;nbsp;</td></tr><tr><td>5-Fluoroorotic acid (5-FOA)</td><td>AmericanBio</td><td>AB04067-00005</td><td>for&amp;nbsp; 5-FOA medium</td></tr></tbody></table>

targeted in situ mutagenesis of histone genes in budding yeast

We describe a PCR- and homologous recombination-based system for generating targeted mutations in histone genes in budding yeast cells. The resulting mutant alleles reside at their endogenous genomic sites and no exogenous DNA sequences are left in the genome following the procedure. Since in haploid yeast cells each of the four core histone proteins is encoded by two non-allelic genes with highly homologous open reading frames (ORFs), targeting mutagenesis specifically to one of two genes encoding a particular histone protein can be problematic. The strategy we describe here bypasses this problem by utilizing sequences outside, rather than within, the ORF of the target genes for the homologous recombination step. Another feature of this system is that the regions of DNA driving the homologous recombination steps can be made to be very extensive, thus increasing the likelihood of successful integration events. These features make this strategy particularly well-suited for histone gene mutagenesis, but can also be adapted for mutagenesis of other genes in the yeast genome.

Descrevemos a geração de um alelo hht2 expressando uma proteína mutante da histona H3 abrigando uma substituição na posição 53 a partir de uma arginina para um ácido glutâmico (H3-R53E mutante) como um exemplo representativo do alvo na estratégia de mutagénese in situ. Geramos uma estirpe em que toda a ORF de HHT2 é substituído pelo gene URA3 (veja o passo 1 do...

Watch this Scientific Journal Video about Targeted in Situ Mutagenesis of Histone Genes in Budding Yeast at JoVE.com

Mutagênese in situ direcionada de genes de histonas em leveduras em brotamento | Genética | Vídeo

Targeted in Situ Mutagenesis of Histone Genes in Budding Yeast

A strategy for generating mutations in histone genes at their endogenous location in Saccharomyces cerevisiae is presented.

Visadas<em&gt; In Situ</em&gt; mutagénese de histona Genes em brotamento Yeast

We describe a PCR- and homologous recombination-based system for generating targeted mutations in histone genes in budding yeast cells. The resulting ...

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Targeted in Situ Mutagenesis of Histone Genes in Budding Yeast

DNA Structure and Function

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15.3K visualizações.  Hendrix College. A strategy for generating mutations in histone genes at their endogenous location in Saccharomyces cerevisiae is presented. 

Vídeo: Targeted in Situ Mutagenesis of Histone Genes in Budding Yeast

Optogenetic Random Mutagenesis Using Histone-miniSOG in C. elegans

Forward genetic screening in model organisms is the workhorse to discover functionally important genes and pathways in many biological processes. In most mutagenesis-based screens, researchers have relied on the use of toxic chemicals, carcinogens, or irradiation, which requires designated equipment, safety setup, and/or disposal of hazardous materials. We have developed a simple approach to induce heritable mutations in C. elegans using germline-expressed histone-miniSOG, a light-inducible potent generator of reactive oxygen species. This mutagenesis method is free of toxic chemicals and requires minimal laboratory safety and waste management. The induced DNA modifications include single-nucleotide changes and small deletions, and complement those caused by classical chemical mutagenesis. This methodology can also be used to induce integration of extrachromosomal transgenes. Here, we provide the details of the LED setup and protocols for standard mutagenesis and transgene integration.

Optogenetic Random Mutagenesis Using Histone-miniSOG in C. elegans

Genetically-encoded histone-miniSOG induces genome-wide heritable mutations in a blue&#160;light-dependent manner. This mutagenesis method is simple, fast, free of toxic chemicals, and well-suited for forward genetic screening and transgene integration.

A mutagénese aleatória optogenetic Usando Histona-miniSOG em<em&gt; C. elegans</em

Forward genetic screening in model organisms is the workhorse to discover functionally important genes and pathways in many biological processes. In most ...

Genética

Chromatin Immunoprecipitation (ChIP) of Histone Modifications from Saccharomyces cerevisiae

Histone post-translational modifications (PTMs), such as acetylation, methylation and phosphorylation, are dynamically regulated by a series of enzymes that add or remove these marks in response to signals received by the cell. These PTMS are key contributors to the regulation of processes such as gene expression control and DNA repair. Chromatin immunoprecipitation (chIP) has been an instrumental approach for dissecting the abundance and localization of many histone PTMs throughout the genome in response to diverse perturbations to the cell. Here, a versatile method for performing chIP of post-translationally modified histones from the budding yeast Saccharomyces cerevisiae (S. cerevisiae) is described. This method relies on crosslinking of proteins and DNA using formaldehyde treatment of yeast cultures, generation of yeast lysates by bead beating, solubilization of chromatin fragments by micrococcal nuclease, and immunoprecipitation of histone-DNA complexes. DNA associated with the histone mark of interest is purified and subjected to quantitative PCR analysis to evaluate its enrichment at multiple loci throughout the genome. Representative experiments probing the localization of the histone marks H3K4me2 and H4K16ac in wildtype and mutant yeast are discussed to demonstrate data analysis and interpretation. This method is suitable for a variety of histone PTMs and can be performed with different mutant strains or in the presence of diverse environmental stresses, making it an excellent tool for investigating changes in chromatin dynamics under different conditions.

Chromatin Immunoprecipitation ChIP of Histone Modifications from Saccharomyces cerevisiae

Here, we describe a protocol for chromatin immunoprecipitation of modified histones from the budding yeast Saccharomyces cerevisiae. Immunoprecipitated DNA is subsequently used for quantitative PCR to interrogate the abundance and localization of histone post-translational modifications throughout the genome.

Imunoprecipitação de Cromatina (ChIP) de Modificações de Histonas de Saccharomyces cerevisiae

Histone post-translational modifications (PTMs), such as acetylation, methylation and phosphorylation, are dynamically regulated by a series of enzymes ...

Gene-targeted Random Mutagenesis to Select Heterochromatin-destabilizing Proteasome Mutants in Fission Yeast

Random mutagenesis of a target gene is commonly used to identify mutations that yield the desired phenotype. Of the methods that may be used to achieve random mutagenesis, error-prone PCR is a convenient and efficient strategy for generating a diverse pool of mutants (i.e., a mutant library). Error-prone PCR is the method of choice when a researcher seeks to mutate a pre-defined region, such as the coding region of a gene while leaving other genomic regions unaffected. After the mutant library is amplified by error-prone PCR, it must be cloned into a suitable plasmid. The size of the library generated by error-prone PCR is constrained by the efficiency of the cloning step. However, in the fission yeast, Schizosaccharomyces pombe, the cloning step can be replaced by the use of a highly efficient one-step fusion PCR to generate constructs for transformation. Mutants of desired phenotypes may then be selected using appropriate reporters. Here, we describe this strategy in detail, taking as an example, a reporter inserted at centromeric heterochromatin.

This article describes a detailed methodology for random mutagenesis of a target gene in fission yeast. As an example, we target rpt4+, which encodes a subunit of the 19S proteasome, and screen for mutations that destabilize heterochromatin.

Gene-alvo Mutagenesis aleatório para selecionar heterocromatina-desestabilizando Proteassoma mutantes no fermento de fissão

Random mutagenesis of a target gene is commonly used to identify mutations that yield the desired phenotype. Of the methods that may be used to achieve ...

Single Molecule Fluorescence In Situ Hybridization (smFISH) Analysis in Budding Yeast Vegetative Growth and Meiosis

Single molecule fluorescence in situ hybridization (smFISH) is a powerful technique to study gene expression in single cells due to its ability to detect and count individual RNA molecules. Complementary to deep sequencing-based methods, smFISH provides information about the cell-to-cell variation in transcript abundance and the subcellular localization of a given RNA. Recently, we have used smFISH to study the expression of the gene&#160;NDC80&#160;during meiosis in budding yeast, in which two transcript isoforms exist and the short transcript isoform has its entire sequence shared with the long isoform. To confidently identify each transcript isoform, we optimized known smFISH protocols and obtained high consistency and quality of smFISH data for the samples acquired during budding yeast meiosis. Here, we describe this optimized protocol, the criteria that we use to determine whether high quality of smFISH data is obtained, and some tips for implementing this protocol in&#160;other yeast strains and growth conditions.

Single Molecule Fluorescence In Situ Hybridization smFISH Analysis in Budding Yeast Vegetative Growth and Meiosis

This single molecule fluorescence in situ hybridization protocol is optimized to quantify the number of RNA molecules in budding yeast during vegetative growth and meiosis.

Única molécula fluorescência In Situ Hybridization (smFISH) análise em Budding fermento crescimento vegetativo e meiose

Single molecule fluorescence in situ hybridization (smFISH) is a powerful technique to study gene expression in single cells due to its ability to detect ...

Characterizing Histone Post-translational Modification Alterations in Yeast Neurodegenerative Proteinopathy Models

Neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS) and Parkinson&#39;s disease (PD), cause the loss of hundreds of thousands of lives each year. Effective treatment options able to halt disease progression are lacking. Despite the extensive sequencing efforts in large patient populations, the majority of ALS and PD cases remain unexplained by genetic mutations alone. Epigenetics mechanisms, such as the post-translational modification of histone proteins, may be involved in neurodegenerative disease etiology and progression and lead to new targets for pharmaceutical intervention. Mammalian in vivo and in vitro models of ALS and PD are costly and often require prolonged and laborious experimental protocols. Here, we outline a practical, fast, and cost-effective approach to determining genome-wide alterations in histone modification levels using Saccharomyces cerevisiae as a model system. This protocol allows for comprehensive investigations into epigenetic changes connected to neurodegenerative proteinopathies that corroborate previous findings in different model systems while significantly expanding our knowledge of the neurodegenerative disease epigenome.

This protocol outlines experimental procedures to characterize genome-wide changes in the levels of histone post-translational modifications (PTM) occurring in connection with the overexpression of proteins associated with ALS and Parkinson&#39;s disease in Saccharomyces cerevisiae models. After SDS-PAGE separation, individual histone PTM levels are detected with modification-specific antibodies via Western blotting.

Caracterizando a histona modificação pós-traducional alterações nos modelos de Neurodegenerative Proteinopathy de levedura

Neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS) and Parkinson&#39;s disease (PD), cause the loss of hundreds of thousands of lives ...

A Deep-sequencing-assisted, Spontaneous Suppressor Screen in the Fission Yeast Schizosaccharomyces pombe

A genetic screen for mutant alleles that suppress phenotypic defects caused by a mutation is a powerful approach to identify genes that belong to closely related biochemical pathways. Previous methods such as the Synthetic Genetic Array (SGA) analysis, and random mutagenesis techniques using ultraviolet (UV) or chemicals like ethyl methanesulfonate (EMS) or N-ethyl-N- nitrosourea (ENU), have been widely used but are often costly and laborious. Also, these mutagen-based screening methods are frequently associated with severe side effects on the organism, inducing multiple mutations that add to the complexity of isolating the suppressors. Here, we present a simple and effective protocol to identify suppressor mutations in mutants which confer a growth defect in Schizosaccharomyces pombe. The fitness of cells with a growth deficiency in standard rich liquid media or synthetic liquid media can be monitored for recovery using an automated 96-well plate reader over an extended period. Once a cell acquires a suppressor mutation in the culture, its descendants outcompete those of the parental cells. The recovered cells that have a competitive growth advantage over the parental cells can then be isolated and backcrossed with the parental cells. The suppressor mutations are then identified using whole-genome sequencing. Using this approach, we have successfully isolated multiple suppressors that alleviate the severe growth defects caused by loss of Elf1, an AAA+ family ATPase that is important in nuclear mRNA transport and maintenance of genomic stability. There are currently over 400 genes in S. pombe with mutants conferring a growth defect. As many of these genes are uncharacterized, we propose that our method will hasten the identification of novel functional interactions with this user-friendly, high-throughput approach.

A Deep-sequencing-assisted, Spontaneous Suppressor Screen in the Fission Yeast Schizosaccharomyces pombe

We present a simple suppressor screen protocol in fission yeast. This method is efficient, mutagen-free, and&#160; selective&#160; for&#160; mutations that&#160; often&#160; occur at&#160; &#160;a&#160; single&#160; genomic&#160; locus.&#160; The protocol is suitable for isolating suppressors that alleviate growth defects in liquid culture that are caused by a mutation or a drug.

Uma tela de supressor de Deep-sequenciamento-assistida, espontânea na fissão levedura Schizosaccharomyces pombe

A genetic screen for mutant alleles that suppress phenotypic defects caused by a mutation is a powerful approach to identify genes that belong to closely ...

Genetic Studies of Human DNA Repair Proteins Using Yeast as a Model System 

Understanding the roles of human DNA repair proteins in genetic pathways is a formidable challenge to many researchers. Genetic studies in mammalian systems have been limited due to the lack of readily available tools including defined mutant genetic cell lines, regulatory expression systems, and appropriate selectable markers. To circumvent these difficulties, model genetic systems in lower eukaryotes have become an attractive choice for the study of functionally conserved DNA repair proteins and pathways. We have developed a model yeast system to study the poorly defined genetic functions of the Werner syndrome helicase-nuclease (WRN) in nucleic acid metabolism. Cellular phenotypes associated with defined genetic mutant backgrounds can be investigated to clarify the cellular and molecular functions of WRN through its catalytic activities and protein interactions. The human WRN gene and associated variants, cloned into DNA plasmids for expression in yeast, can be placed under the control of a regulatory plasmid element. The expression construct can then be transformed into the appropriate yeast mutant background, and genetic function assayed by a variety of methodologies. Using this approach, we determined that WRN, like its related RecQ family members BLM and Sgs1, operates in a Top3-dependent pathway that is likely to be important for genomic stability. This is described in our recent publication [1] at <a href="http://www.impactaging.com">www.impactaging.com</a>. Detailed methods of specific assays for genetic complementation studies in yeast are provided in this paper.

Genetic Studies of Human DNA Repair Proteins Using Yeast as a Model System

Genetic studies in yeast can be employed to investigate the molecular and cellular functions of human genes in cellular DNA metabolism. Methods are described for the genetic characterization of the human WRN gene product defective in the premature aging disorder Werner syndrome in functionally conserved pathways using yeast as a tractable model system.

Estudos genéticos de proteínas de reparo do DNA Humano Utilizando Levedura como um sistema modelo

Understanding the roles of human DNA repair proteins in genetic pathways is a formidable challenge to many researchers.  Genetic studies in mammalian ...

Biologia

Isolamento de cromatina específico de locus de células de levedura

Single-Copy Gene Locus Chromatin Purification in Saccharomyces cerevisiae

The basic organizational unit of eukaryotic chromatin is the nucleosome core particle (NCP), which comprises DNA wrapped ~1.7 times around a histone octamer. Chromatin is defined as the entity of NCPs and numerous other protein complexes, including transcription factors, chromatin remodeling and modifying enzymes. It is still unclear how these protein-DNA interactions are orchestrated at the level of specific genomic loci during different stages of the cell cycle. This is mainly due to the current technical limitations, which make it challenging to obtain precise measurements of such dynamic interactions. Here, we describe an improved method combining site-specific recombination with an efficient single-step affinity purification protocol to isolate a single-copy gene locus of interest in its native chromatin state. The method allows for the robust enrichment of the target locus over genomic chromatin, making this technique an effective strategy for identifying and quantifying protein interactions in an unbiased and systematic manner, for example by mass spectrometry. Further to such compositional analyses, native chromatin purified by this method likely reflects the in vivo situation regarding nucleosome positioning and histone modifications and is, therefore, amenable to further structural and biochemical analyses of chromatin derived from virtually any genomic locus in yeast.

Autor em destaque: Avançando na pesquisa da cromatina e superando as limitações com um protocolo de isolamento de cromatina específico para locus de alto enriquecimento 

This protocol presents a locus-specific chromatin isolation method based on site-specific recombination to purify a single-copy gene locus of interest in its native chromatin context from budding yeast, Saccharomyces cerevisiae.

Purificação de cromatina de locus gênico de cópia única em Saccharomyces cerevisiae

The basic organizational unit of eukaryotic chromatin is the nucleosome core particle (NCP), which comprises DNA wrapped ~1.7 times around a histone ...

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