Presence of complementary RNA in chicken sarcoma cells and Rous sarcoma virus

The subcellular localization of nucleotide sequences in Rous chicken sarcoma complementary to RNA of Rous sarcoma virus was investigated by RNA-RNA molecular hybridization. Samples of virion RNA labeled with radioactive iodine (¹²⁵I) were annealed with RNA from different fractions (nuclei, mitochondria, free and membrane-bound polysomes) isolated from Rous chicken sarcoma cells. The formation of RNase-resistant hybrids between virus RNA-¹²⁵I and RNA from mitochondria and membrane-bound polysomes was demonstrated; the relative frequency of occurrence of sequences complementary to virion RNA in the latter, moreover, was 446 times greater than in the former. The role of complementary ribonucleotide sequences is discussed.Laboratory of Biochemistry, N. N. Petrov Research Institute of Oncology, Ministry of Health of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR A. N. Klimov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 3, pp. 332–334, March, 1978.     

Integration of avian sarcoma virus DNA in chicken cells

Host-range and host-range deletion mutants of type 5 adenovirus belonging to two complementation groups, whose mutational lesions map physically within the left 11% of the type 5 genome, were efficiently complemented in mixed infection by type 12 adenovirus. The complementation of these early function mutants by type 12 is in contrast to the lack of complementation found previously for two other groups of early function mutants, and it is consistent with functional relatedness between products encoded by early region 1 of the respective serotypes. No evidence for recombination between the type 5 mutants and type 12 was found.     

Presence of chicken cell surface antigen on Rous virus activated in heterokaryons of transformed non-permissive hamster cells and chicken cells.

Incubation with antiserum to chick embryo (CE) cells, in the presence of complement, inactivates Rous sarcoma virus (RSV) produced by heterokaryons formed by non-permissive RSV-transformed hamster cells and CE cells as well as RSV produced by heterokaryons is observed following incubation with antiserum to the transformed hamster cells, plus complement. Hence, the envelope of RSV activated in heterokaryons, as that of RSV produced by CE cells, must contain a surface antigen of the CE cell, and the virus must mature only, or preferentially, at chicken-specific sites of the heterokaryon surface.     

Presence of antigen common to avian tumor viral envelope antigen in normal chick embryo cells

Antiserum against the envelope antigen of avian tumor virus of subgroup E was obtained from chickens bearing tumors induced by RSV(f). The capacity to absorb neutralizing activity from the antiserum was used to demonstrate the presence or absence of the envelope antigen in various types of cells. The specificity of the antigen was also confirmed by immuno-electron microscopy. Cell extracts or viable cells from uninfected chick embryos were generally positive for the envelope antigen when the embryos were also positive in both the formation of gs-antigen and helper activity. Chick embryo cells negative for these viral functions were also deficient in the envelope antigen. However, two exceptional embryos were found in which the amount of envelope antigen and the level of helper activity do not directly correlate with each other. The antigen common to that on the viral envelope appeared to be located on or or in the fuzzy coat at the cell surface.     

Antigenic and structural studies on the transforming proteins of Rous sarcoma virus and Yamaguchi 73 avian sarcoma virus

A widely cross reactive antiserum raised against denatured pp60v-src, the transforming protein encoded by Rous sarcoma virus, was used to test antigenic relationships with the transforming gene products encoded by other avian sarcoma viruses. The results showed that P90gag-yes, the transforming protein of a representative of Class III avian sarcoma viruses, is antigenically related to pp60v-src. Tryptic phosphopeptide analysis of P90gag-yes revealed two phosphotyrosine-containing peptides and one phosphoserine-containing peptide. One of the phosphotyrosine-containing peptides comigrated with the phosphotyrosine-containing tryptic peptide from pp60v-src.