APRIL 2 7- 2 8 -MINUTES OF MEETING 
14 
2. v 1776 (pSCIQl) and v 1776 (pCRl) 
At its June 1977 meeting, the RAC adopted explicit criteria 
for host-plasmid systems proposed for EK2 certification. 
At its October-Nov ember 1977 meeting, the RAC passed a motion 
that the systems £776 (pSClOl) and £776 (pCRl) , which were 
certified prior to these criteria, should be rereviewed by 
the plasnid Working Group. Additional data on these systems, 
along with x!776 (pMB9) as a control, were submitted by 
Dr. Roy Curtiss. The Working Group concluded that the data 
show that x 1776 (pCRl) is definitely inferior with regard 
to transmissibility, and recommended that this system should 
not be allowed for any new cloning since superior plasmids 
are available. However, the Working Group recommended that 
existing clones need not be destroyed because £776 (pCRl) 
is safer than required by the Guidelines for an EK2 system. 
The RAC voted unanimously to accept this recommendation. 
The decision concerning pSClOl (and also pMB9) will be 
deferred until the Committee can obtain the following 
data: 
Mobilizing Vector 
EK2 System 
R549 drdl 
Rl drdl9 
R64 drdll 
pMB9 
pSClOl 
pBR322 
Ihe Working Group is requesting that additional data be 
obtained because new data from Roy Curtiss show one plasmid 
which mobilizes pMB9 at a higher rate than previously 
seen, and another plasmid which does the same for pSClOl. 
Ihe Working Group wants to see these experiments repeated, 
with controls, before it reconsiders its policy on acceptable 
limits (which is based on the best performance available) , 
and/or on the status of pMB9 and pSClOl. Dr. Nutter was asked 
to assign this testing to Dr. Clowes. Ihe RAC accepted these 
recommendations . 
3. y!776 (POP2Q3-3) 
The RAC voted unanimously to accept the recommendations of 
the plasmid Working Group to request r-^ x r 2 data from 
Dr. Giorno before acting on his request that pOP203-3 with 
x 1776 be certified as an EK2 host-vector system. F -lac 
should be used as one of the mobilizing plasmids. 
Ihe Working Group noted that the insertion of a 203-base 
pair segment of the lac gene may confer homology with a 
mobilizing plasmid (and must do so in the case of F -lac ) , 
[ 530 ] 
