FIGURE 2 
U3 «5 
«3 U5 
(«*) 
— 0} 
mpo< •*» 
*>3 
a 
Fig. 1. Generalized diagrams of four different configurations of inserted 
proviral DNA, an activated cellular gene and the resulting transcript 
Protein-coding domains art m black boxes, (a) Insertion of the LTR of a 
deleted provirus in the promoter region of a gene, upstream from the first 
coding exon, such as occurs frequently near c- myc. (b) Enhancement 
activation of genes like int and nm by a downstream intact provirus. In this 
example, the brovirus is integrated in the untranslated trailer of the gene, 
leading to a hybrid RNA but to an unaltered protein, (c) Insertion of an 
intact MLV brovirus within c-myb. The pmtein-encoding domain is 
disrupted ana transcription starting from the 5' viral LTR joins viral gig 
sequences to the remainder of c-myb. (dj ALV insertions near c-ts \>-B, 
with similar disruptions to thou in (c), but with a transcript containing 
viral env sequences as well The remaining exons of c-txb-B correspond to 
the intra cellu l a r domain of the EGF receptor. 
(Reference: Nusse, 1986) 
Recombinant DNA Research, Volume 12 
[207] 
