Expression vectors

The vectors described thus far have been designed to facilitate the cloning of genomic DNA/ cDNA sequences, ultimately in order to identify and isolate a gene/cDNA coding for a particular polypeptide. The genetic construction of these vectors normally does not support the actual expression (i.e. transcription and translation) of the gene. Once the gene/cDNA coding for a potential target protein has been isolated, the goal usually becomes one of achieving high levels of expression of this target gene. This process entails ligation of the gene into a vector that will support high-level transcription and translation. In addition to the basic vector elements (e.g. an origin of replication and a selectable marker, such as an antibiotic resistance gene), expression vectors also contain all the genetic elements required to support transcription and translation, as described earlier in this chapter (e.g. promoters, translational start and stop signals, etc.; see Figures 3.7 and 3.8). A wide range of such expression vectors is now commercially available and, obviously, each is tailored to work best in a specific host cell type (e.g. bacterial, yeast, mammalian, etc.). The choice of exact host cell type in which to express a recombinant therapeutic protein will depend upon a number of factors, as described in Chapter 5.

Supplements For Diabetics

Supplements For Diabetics

All you need is a proper diet of fresh fruits and vegetables and get plenty of exercise and you'll be fine. Ever heard those words from your doctor? If that's all heshe recommends then you're missing out an important ingredient for health that he's not telling you. Fact is that you can adhere to the strictest diet, watch everything you eat and get the exercise of amarathon runner and still come down with diabetic complications. Diet, exercise and standard drug treatments simply aren't enough to help keep your diabetes under control.

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