Creative Biolabs has been a long-term expert and market leader in the field of phage display and antibody engineering. Through our unparalleled phage display platform, Creative Biolabs offers integrated service of cDNA library construction to our customers over the globe.
Complementary DNA (cDNA) is the reverse transcript of mRNA. As lacking the large non-coding introns compared to genomic DNA, eukaryotic cDNA libraries represent the coding sequence of all temporally transcribed genes in a certain cell type. Aided by phage display technology, the entire cDNA products can be expressed on the phage surface by fusion proteins, thus allowing identification of a large panel of protein candidates as well as isolating specific binders towards various targets. Over the past decades, phage display cDNA libraries have been widely utilized for antigen/antibody discovery, vaccine design, clinical therapies and diagnosis, etc.
Conventional phage display technique meets obstacles in constructing complex cDNA libraries, such as low concentration of target mRNA, frequent in-frame stop codons due to the 3’ region of poly(A) tail, and constrained structure of original mRNA. These factors result in a poor yield of functional clones, which hinders the development of phage display cDNA libraries for decades. To solve these problems, Creative Biolabs has successfully established multiple unique techniques to generate high-quality cDNA libraries with large capacity, high density, and correct orientation.
The standard procedure to construct phage display cDNA libraries is performed in following steps:
In addition, Creative Biolabs is confident in tailoring impeccable phage display cDNA libraries of diverse types, including:
Standard cDNA Library
In case urgent use for straightforward screening and downstream application is required, we can construct standard cDNA libraries with at least 3×106 primary clones with an average insert size of at least 1 kb. We guarantee that all the clones are properly oriented for expression, antibody screening or isolation of specific cDNA clones.
Full-length cDNA Library
Our novel full-length cDNA synthesis procedure combines a proprietary process for reducing RNase H reverse transcriptase activity with unique techniques for mRNA isolation, 5’ cap full-length enrichment, and reduction of oligo (dT) priming. Together, these steps greatly enhance the likelihood of constructing a library with full-length inserts, ensuring high success rate of subsequent screening.
Normalized cDNA Library
Special normalization procedures of Creative Biolabs can decrease the prevalence of clones with medium and high abundance, thus effectively eliminating biased sequencing. Therefore, normalized cDNA libraries can be a powerful tool for rare gene discovery.
Subtractive cDNA Library
This technique is exceptionally appropriate when the target gene is assumed to express in poor level. With proprietary self-subtraction and tissue-tissue subtraction techniques, we are able to reduce irrelevant abundant sequences 10-100 folds, making it easier to find desired targets.
In Creative Biolabs, either M13 or T7 phage system are available for cDNA library construction according to varied objectives. Meanwhile, we also provide cDNA library constructed via lambda phage vector as an alternative. Based on extensive experience and our versatile phage display platform, Creative Biolabs is specialized in constructing high-quality custom cDNA libraries. Scientists of Creative Biolabs will formulate a comprehensive and systematic plan using the most advanced techniques to deliver our clients’ specific research goal.
Fig 1. Preparation of a bacteriophage cDNA library. (Berk et al. 2000)