Cell Biology Lecture #14 Overview p. 319-331 DNA engineering

"Gene machines"=8 bases in 1980s, 100 bases in 1990s, almost unlimited today (especially using linkage of fragments), however, naturally-occurring =most interesting to start with.

Major proteins = 1% or more of total. Uses of antibodies to purify and detect in situ.

Minor protein functions being evaluated as available (context, timing = important)

Inactivation of gene product allows function to be revealed:

1. Antibody

2. Genetic approaches (human mutants are rare, but identify themselves)

3. Temperature sensitive mutants

Reverse genetics: Start with protein or gene and search for its function

Problem: legal, ethical implications. Young man killed; Carter commission recommendations

"Gene knockout" by homologous recombination

Agrobacterium tumefaciens as vector