Provirus DNA sequences in Rous sarcoma cell genome

Non-producer hamster and virus-producing chicken Rous sarcoma cells contain a complete avian sarcoma virus (ASV)-provirus DNA (pro-DNA). Unlike this, in normal hamster liver DNA to ASV--specific sequences are absent. Moreover, the nuclear chicken Rous sarcoma and chick embryo cell (CEC) DNA preparations contain practically all endogenous chicken virus (ECV)-specific sequences, while the hamster tumor DNA was annealed with only more than half of the ECV-RNA sequences. Thus, the pro-DNA of permissive hosts contains so-called "sarcoma-specific", "common" and "endogenous--specific" nucleotide sequences. The "sarcoma-specific" and "common" sequences are present in the hamster sarcoma pro-DNA, only. Both the pro-DNA of permissive cells and the pro-DNA of non-permissive cells consist of moderately reiterated and unique sequences. The "common" regions of pro-DNA are localized, mainly, in the unique zone, while "sarcoma-specific" and "endogenous-specific" sequences of pro-DNA - in the moderately reiterated and unique zones. The pro-DNA organization of permissive and non-permissive hosts is discussed.