Biomaterial Database

Optimised cDNA size selection and cloning procedure for the construction of representative plasmid cDNA libraries. 1991

B L Kieffer

Ecole Supérieure de Biotechnologie, Strasbourg, France.

Plasmid libraries are more versatile than phage libraries since they allow expression cloning in eukaryotic systems. However, high numbers of primary clones are sometimes difficult to obtain and more efficient transformation procedures are often required. In this paper, a detailed protocol is presented, for the construction of large plasmid libraries from ng quantities of cDNA, based on a highly efficient transformation step. Drop dialysis and electroporation are optimised: complete ligase removal and yeast tRNA addition before dialysis appear critical, while exclusive use of double-distilled water as well as rapid preparation of fresh cells provide excellent electroporation yields. A novel, simple and flexible cDNA size selection procedure is also presented, based on sucrose density gradient. Two libraries were constructed using an expression vector for mammalian cells (pCDM8) and its Escherichia coli host strain (MC1061[p3]). Numbers of 2 to 10 x 10(6) primary transformants were obtained from 1 microgram of poly(A)+ RNA. Up to 85% of the clones had inserts and half of the inserts were larger than 1.5 kb.

UI	MeSH Term	Description	Entries
D010957	Plasmids	Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.	Episomes,Episome,Plasmid
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D004277	DNA, Single-Stranded	A single chain of deoxyribonucleotides that occurs in some bacteria and viruses. It usually exists as a covalently closed circle.	Single-Stranded DNA,DNA, Single Stranded,Single Stranded DNA
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D005822	Genetic Vectors	DNA molecules capable of autonomous replication within a host cell and into which other DNA sequences can be inserted and thus amplified. Many are derived from PLASMIDS; BACTERIOPHAGES; or VIRUSES. They are used for transporting foreign genes into recipient cells. Genetic vectors possess a functional replicator site and contain GENETIC MARKERS to facilitate their selective recognition.	Cloning Vectors,Shuttle Vectors,Vectors, Genetic,Cloning Vector,Genetic Vector,Shuttle Vector,Vector, Cloning,Vector, Genetic,Vector, Shuttle,Vectors, Cloning,Vectors, Shuttle
D014169	Transformation, Bacterial	The heritable modification of the properties of a competent bacterium by naked DNA from another source. The uptake of naked DNA is a naturally occuring phenomenon in some bacteria. It is often used as a GENE TRANSFER TECHNIQUE.	Bacterial Transformation
D015723	Gene Library	A large collection of DNA fragments cloned (CLONING, MOLECULAR) from a given organism, tissue, organ, or cell type. It may contain complete genomic sequences (GENOMIC LIBRARY) or complementary DNA sequences, the latter being formed from messenger RNA and lacking intron sequences.	DNA Library,cDNA Library,DNA Libraries,Gene Libraries,Libraries, DNA,Libraries, Gene,Libraries, cDNA,Library, DNA,Library, Gene,Library, cDNA,cDNA Libraries