EFFECTS OF FOWL SARCOMA VIRUS ON P32 INCORPORATION INTO NUCLEIC ACID IN CHICKEN THYMUS GLAND

P32 uptake into DNA and RNA of chicken thymus gland in vitro was investigated at different stages of tumorigenesis caused by chicken sarcoma virus (Chiba's strain). (1) The specific activities for the different portions of tumor were compared. The solid portion and the rudimentary thymus gland were on a similar level and the jelly-like portion was lower. (2) From the 3rd to 7th day after virus inoculation, the specific activity of RNA was depressed, and from the 8th day this value increased compared with that of control. Specific activity of DNA changed also accompanied that of RNA. From the above findings it was concluded that specific activities of RNA and DNA express cell reproduction, and there was no expression of the activity of RNA and DNA fractions ocurred from the 3rd to 7th day after virus infection, but the reason of this decrease is at present not clarified.