WordNet

a depository built to contain books and other materials for reading and study (同)depository library
a building that houses a collection of books and other materials
a room where books are kept; "they had brandy in the library"
(computing) a collection of standard programs and subroutines that are stored and available for immediate use (同)program library, subroutine library
a collection of literary documents or records kept for reference or borrowing

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『図書館』,図書室 / (個人の)書斎,読書室 / 『蔵書』 / 双書

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/05/15 23:37:31」(JST)

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A cDNA library is a combination of cloned cDNA (complementary DNA) fragments inserted into a collection of host cells, which together constitute some portion of the transcriptome of the organism. cDNA is produced from fully transcribed mRNA found in the nucleus and therefore contains only the expressed genes of an organism. Similarly, tissue-specific cDNA libraries can be produced. In eukaryotic cells the mature mRNA is already spliced, hence the cDNA produced lacks introns and can be readily expressed in a bacterial cell. While information in cDNA libraries is a powerful and useful tool since gene products are easily identified, the libraries lack information about enhancers, introns, and other regulatory elements found in a genomic DNA library.

cDNA Library Construction

Formation of a cDNA library.

cDNA is created from a mature mRNA from a eukaryotic cell with the use of an enzyme known as reverse transcriptase. In eukaryotes, a poly-(A) tail (consisting of a long sequence of adenine nucleotides) distinguishes mRNA from tRNA and rRNA and can therefore be used as a primer site for reverse transcription. This has the problem that not all transcripts, such as those for the histone, encode a poly-A tail.

mRNA extraction

Firstly, the mRNA is obtained and purified from the rest of the RNAs. Several methods exist for purifying RNA such as trizol extraction and column purification. Column purification is done by using oligomeric dT nucleotide coated resins where only the mRNA having the poly-A tail will bind. The rest of the RNAs are eluted out. The mRNA is eluted by using eluting buffer and some heat to separate the mRNA strands from oligo-dT.

cDNA construction

Once mRNA is purified, oligo-dT (a short sequence of deoxy-thymine nucleotides) is tagged as a complementary primer which binds to the poly-A tail providing a free 3'-OH end that can be extended by reverse transcriptase to create the complementary DNA strand. Now, the mRNA is removed by using a RNAse enzyme leaving a single stranded cDNA (sscDNA). This sscDNA is converted into a double stranded DNA with the help of DNA polymerase. However, for DNA polymerase to synthesize a complementary strand a free 3'-OH end is needed. This is provided by the sscDNA itself by generating a hairpin loop at the 3' end by coiling on itself. The polymerase extends the 3'-OH end and later the loop at 3' end is opened by the scissoring action of S₁ nuclease. Restriction endonucleases and DNA ligase are then used to clone the sequences into bacterial plasmids.

The cloned bacteria are then selected, commonly through the use of antibiotic selection. Once selected, stocks of the bacteria are created which can later be grown and sequenced to compile the cDNA library.

cDNA Library uses

cDNA libraries are commonly used when reproducing eukaryotic genomes, as the amount of information is reduced to remove the large numbers of non-coding regions from the library. cDNA libraries are used to express eukaryotic genes in prokaryotes. Prokaryotes do not have introns in their DNA and therefore do not possess any enzymes that can cut it out during transcription process. cDNA does not have introns and therefore can be expressed in prokaryotic cells. cDNA libraries are most useful in reverse genetics where the additional genomic information is of less use. Also, it is useful for subsequently isolating the gene that codes for that mRNA.

cDNA Library vs. Genomic DNA Library

cDNA library lacks the non-coding and regulatory elements found in genomic DNA. Genomic DNA libraries provide more detailed information about the organism, but are more resource-intensive to generate and maintain.

Cloning of cDNA

cDNA molecules can be cloned by using restriction site linkers. Linkers are short, double stranded pieces of DNA (oligodeoxyribonucleotide) about 8 to 12 nucleotide pairs long that include a restriction endonuclease cleavage site e.g. BamHI. Both the cDNA and the linker have blunt ends which can be ligated together using a high concentration of T4 DNA ligase. Then sticky ends are produced in the cDNA molecule by cleaving the cDNA ends (which now have linkers with an incorporated site) with the appropriate endonuclease. A cloning vector (plasmid) is then also cleaved with the appropriate endonuclease. Following "sticky end" ligation of the insert into the vector the resulting recombinant DNA molecule is transferred into E. coli host cell for cloning.

External links

cDNA library-Properties
Functional Annotation of the Mouse database (FANTOM)
examples of cDNA synthesis and cloning
Custom cDNA Library Construction

UpToDate Contents

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1. 環境中のアレルゲンサンプリング allergen sampling in the environment
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5. 臨床腫瘍学における遺伝子発現プロファイリング、プロテオミクス、およびマイクロRNAプロファイリングの概要 overview of gene expression profiling proteomics and microrna profiling in clinical oncology

English Journal

Diversification of 13S globulins, allergenic seed storage proteins, of common buckwheat.

Sano M1, Nakagawa M1, Oishi A1, Yasui Y1, Katsube-Tanaka T2.Author information 1Graduate School of Agriculture, Kyoto University, Kitashirakawa, Kyoto 606-8502, Japan.2Graduate School of Agriculture, Kyoto University, Kitashirakawa, Kyoto 606-8502, Japan. Electronic address: tanakato@kais.kyoto-u.ac.jp.AbstractThe α polypeptide of the 13S globulin subunit of common buckwheat is the counterpart of the major allergenic β polypeptide. Trypsin digestibility varies between variants of the α polypeptide with and without a tandem repeat insert. To evaluate the intra-species diversity of 13S globulin, the comprehensive screening of a genomic DNA library was performed, resulting in the isolation of 14 and 3 genes for Met-poor and Met-rich subunits, respectively. Although most tandem repeat units were 45 bp in length, the two-repeat gene Glb2B and all one-repeat genes contained an additional 3 bp. Secondary structure predictions and polyacrylamide gel electrophoresis demonstrated that the sense strand of Glb2B-CCG, the additional 3 bp-deletion clone of Glb2B, formed a more rigid secondary structure than that of the wild-type. Thus, the large intra-species variation of 13S globulin revealed in this study and its diversification might be attributable to the unique nature of the tandem repeat sequences.
Food chemistry.Food Chem.2014 Jul 15;155:192-8. doi: 10.1016/j.foodchem.2014.01.047. Epub 2014 Jan 24.
The α polypeptide of the 13S globulin subunit of common buckwheat is the counterpart of the major allergenic β polypeptide. Trypsin digestibility varies between variants of the α polypeptide with and without a tandem repeat insert. To evaluate the intra-species diversity of 13S globulin, the comp
PMID 24594174

Antarease-like Zn-metalloproteases are ubiquitous in the venom of different scorpion genera.

Ortiz E1, Rendón-Anaya M2, Rego SC3, Schwartz EF3, Possani LD4.Author information 1Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autonóma de México, Avenida Universidad 2001, Cuernavaca 62210, Mexico.2Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Km 9.6 Libramiento Norte Carretera León, Irapuato, Guanajuato 36821, Mexico.3Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF 70910-900, Brazil.4Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autonóma de México, Avenida Universidad 2001, Cuernavaca 62210, Mexico. Electronic address: possani@ibt.unam.mx.AbstractBACKGROUND: The venoms of several scorpion species have long been associated with pancreatitis in animal models and humans. Antarease, a Zn-metalloprotease from Tityus serrulatus, is able to penetrate intact pancreatic tissue and disrupts the normal vesicular traffic necessary for secretion, so it could play a relevant role in the onset of acute pancreatitis.
Biochimica et biophysica acta.Biochim Biophys Acta.2014 Jun;1840(6):1738-46. doi: 10.1016/j.bbagen.2013.12.012. Epub 2013 Dec 19.
BACKGROUND: The venoms of several scorpion species have long been associated with pancreatitis in animal models and humans. Antarease, a Zn-metalloprotease from Tityus serrulatus, is able to penetrate intact pancreatic tissue and disrupts the normal vesicular traffic necessary for secretion, so it c
PMID 24361608

Lucimycin, an antifungal peptide from the therapeutic maggot of the common green bottle fly Lucilia sericata.

Pöppel AK, Koch A, Kogel KH, Vogel H, Kollewe C, Wiesner J, Vilcinskas A.AbstractAbstract We report the identification, cloning, heterologous expression and functional characterization of a novel antifungal peptide named lucimycin from the common green bottle fly Lucilia sericata. The lucimycin cDNA was isolated from a library of genes induced during the innate immune response in L. sericata larvae, which are used as therapeutic maggots. The peptide comprises 77 amino acid residues with a molecular mass of 8.2 kDa and a pI of 6.6. It is predicted to contain a zinc-binding motif and to form a random coil, lacking β-sheets or other secondary structures. Lucimycin was active against fungi from the phyla Ascomycota, Basidiomycota and Zygomycota, in addition to the oomycete Phytophtora parasitica, but it was inactive against bacteria. A mutant version of lucimycin, lacking the four C-terminal amino acid residues, displayed 40-fold lower activity. The activity of lucimycin against a number of highly-destructive plant pathogens could be exploited to produce transgenic crops that are resistant against fungal diseases.
Biological chemistry.Biol Chem.2014 Jun 1;395(6):649-56. doi: 10.1515/hsz-2013-0263.
Abstract We report the identification, cloning, heterologous expression and functional characterization of a novel antifungal peptide named lucimycin from the common green bottle fly Lucilia sericata. The lucimycin cDNA was isolated from a library of genes induced during the innate immune response i
PMID 24622788

Japanese Journal

The Golgin Tether Giantin Regulates the Secretory Pathway by Controlling Stack Organization within Golgi Apparatus

Koreishi Mayuko,Gniadek Thomas J.,Yu Sidney,Masuda Junko,Honjo Yasuko,Satoh Ayano
PLoS ONE 8(3), 2013-05-21
… The exogenous expression of mammalian giantin cDNA in S2 cells resulted in clustered Golgi stacks, similar to the Golgi ribbon in mammalian cells. …
NAID 120005311978

Analysis of salivary gland transcripts of the sand fly Lutzomyia ayacuchensis, a vector of Andean-type cutaneous leishmaniasis

Kato Hirotomo,Jochim Ryan C.,Gomez Eduardo A.,Uezato Hiroshi,Mimori Tatsuyuki,Korenaga Masataka,Sakurai Tatsuya,Katakura Ken,Valenzuela Jesus G.,Hashiguchi Yoshihisa
Infection, Genetics and Evolution 13, 56-66, 2013-01-00
… In the present study, the salivary gland transcripts of Lutzomyia (Lu.) ayacuchensis, a vector of cutaneous leishmaniasis in Ecuadorian and Peruvian Andes, were analyzed by sequencing randomly selected clones of the salivary gland cDNA library of this sand fly. …
NAID 120005228370

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★リンクテーブル★

リンク元	「cDNAライブラリー」「gene library」「DNA library」
拡張検索	「equalized cDNA library」「normalized cDNA library」
関連記事	「library」「cDNA」