LIFE 102 Lecture Notes - Yeast Artificial Chromosome, Southern Blot, Molecular Cloning
Document Summary
After a gene has been cloned, its protein product can be produced in larger amounts for research. Cloned genes can be expressed as protein in either bacterial or eukaryotic cells. Several technical difficulties hinder expression of cloned eukaryotic genes in bacterial host cells. To overcome differences in promoters and other dna control sequences, scientists usually employ an expression vector, a cloning vector that contains a highly active prokaryotic promoter. The use of cultured eukaryotic cells as host cells and yeast artificial chromosomes (yacs) as vectors helps avoid gene expression problems. Yacs behave normally in mitosis and can carry more dna than a plasmid. Eukaryotic hosts can provide the post-translational modifications that many proteins require. One method of introducing recombinant dna into eukaryotic cells is electroporation, applying a brief electrical pulse to create temporary holes in plasma membranes. Alternatively, scientists can inject dna into cells using microscopically thin needles.
