Role of the C Region in Relative Growth Rates of Endogenous and Exogenous Avian Oncoviruses (original) (raw)

1. P. N. Tsichlis* and
2. J. M. Coffin†
3. *Department of Medicine, and †Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111; and Tufts Cancer Research Center, Boston, Massachusetts 02111

Excerpt

The avian oncoviruses can be divided into two distinct categories: (1) endogenous viruses that are spontaneously expressed or can be induced from normal uninfected chicken cells (for review, see Robinson 1978), and (2) exogenous viruses originally isolated from spontaneously arising chicken neoplasms. Table 1 shows the genetic constitution of RAV-0, a typical nondefective endogenous virus of chickens, and a representative of the three major types of exogenous virus: PRB RSV, a nondefective transforming virus; _td_PRB-RSV, a transformation-defective (td) mutant of PRB RSV that is biologically identical to lymphoid leukosis virus (although it may have an additional sequence between env and C); and MC29, a defective acute leukemia virus.

RAV-0 has been extensively studied in this laboratory and elsewhere (Coffin et al. 1978; Neiman et al. 1977) by comparison of its 70S genomic RNA with that of nondefective sarcoma virus. The two genomes are almost identical in the 5′ half (gag...