Legend to Fig 2 - RNA blot analysis of NIH 3T3 cells infected with recombinant 
viruses 
A high titer virus preparation obtained from the PA12 packaging cell line was 
used to infect NIH 3T3 cells at an M.O.I. of 0.01-0.1 Neo infectious units per 
cell; 10^-10^ infected cells were isolated by selection with G418, pooled and 
expanded for further analysis. Cytoplasmic polyA RNA was subjected to 
electrophoresis in 1% formaldehyde-agarose gels blotted to nitrocellulose paper 
and hybridized with a -*2p labelled probe (see below). The migration of 
ribosomal 23S and 18S RNA species is indicated. 
In panel A, the -* 2 P labelled probe was the 1300 bp EcoR-AccI DNA fragment 
corresponding to the human ADA cDNA (19), which does not hybridize to the 
endogenous mouse ADA RNA. The 32 P labelled probe in panel B was a 178 bp 
Ball-Kpnl DNA fragment derived from the M-MuLV LTR, specific for the 5' end of 
the RNA transcripts expressed from the vectors shown in Fig IB. In panel C, a 
Neo specific 32 P labelled probe was used and in panel D the RNA blot was 
hybridized with the human ADA-specific probe described in panel A. 
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Recombinant DNA Research, Volume 12 
