52 
May I have the next slide, please (14)? 
Slide 14 
Guidelines for Experiments with E. coli "Host-Vector" Systems V. 
"Foreign” DNA = Extrachromosomal DNA elements (purified) 
"Foreign" DNA Source 
Physical 
Containment 
Biological 
Animal Viruses 
P4 
or 
EK2 
P3 
EK3 
if cloned, free of harmful genes 
P3 
EK2 
Plant Viruses 
P3 
or 
EK1 
P2 
EK2 
Eukaryote Organelle: 
primates 
P3 
or 
EK1 
P2 
EK2 
Other 
P2 
EK1 
Prokaryote (plasmids and phage) 
"Exchangers" 
non-pathogens 
PI 
EK1 
pathogen 
As for shotgun (P2 EK1) 
"Non-exchangers" 
As for shotgun (P2 EK1) 
If 'drug' problem 
P3 
EK2 
The final group of experiments utilizing IS. coli host-vector systems 
are those in which the foreign DNA is itself from an extra- chromosomal ele- 
ment; and as I indicated before, it is assumed that such DNA is purified 
away from the chromosomal DNA prior to the recombination. Various possible 
sources of extra-chromosomal DNA are listed, and the recommended combined 
containment given. 
For example, DNA from animal viruses requires P4 physical containment 
and an EK2 host-vector system, or alternatively, P3 physical containment and 
an EK3 host-vector system. If the recombinants have been purified by clon- 
ing and shown to contain only harmless regions of the viral genome, then 
experiments can be moved to P3 and EK2. 
Many of the recombinant DNA experiments currently being talked about 
and planned involve, rather than the use of _E. coli host-vector systems, 
systems in which the host cells are eukaryote cells grown as single cells 
under special laboratory conditions. This is shown on the next slide (15). 
In the middle of the slide is a plate on which such cells are growing. 
The vectors that are available for such experiments include extra chromo- 
somal DNA elements normally found in eukaryote cells which are here called 
organelle DNA, and also the DNA of viruses that infect particular cells of 
interest. Given the current state of technology, viral DNAs are most likely 
to be used as vectors in the near future. 
[193] 
