Influence of the transduced 3'UTR of the c-src oncogene on tumour growth induced by the v-src gene of avian sarcoma virus PR2257.

Avian sarcoma virus PR2257 contains 952 bp transduced from the left part of the 3'UTR of the chicken c-src oncogene. Deletion mutants were constructed to determine the effect of the 3'UTR on tumorigenicity in vivo and in vitro. In the presence of the 3'UTR, tumours were 3.4 times larger in vivo, and tumorigenicity was increased 2.5-fold in vitro. Several regulatory submotifs were also found within the 3'UTR. Parts of the 3'UTR were cloned into the LTR CAT plasmid and analysed for CAT expression. A 170 bp element was found to be responsible for the enhanced expression of the CAT gene. These results demonstrate the effect of the transduced 3'UTR sequence during long-term interaction between PR2257 virus and the chicken genome, and suggest a novel regulatory mechanism of the src oncogene.