Fusion of Rous-sarcoma-virus-transformed rat cells to morphologically normal human or rat cells results in transcriptional suppression of the provirus that depends on its chromosomal integration site

Abstract

The fusion of a Rous sarcoma virus (RSV)-transformed rat fibroblast clone to at least 2 different human cell types reproducibly produces phenotypically normal hybrids. Analysis of such hybrids reveals that proviral silence is the result of transcriptional down-regulation, presumably by a trans-acting human molecule. Furthermore, this phenomenon seems to be strongly influenced by the proviral chromosomal integration site and its imposition may entail a mechanism that is required only transiently.