Infection of chick limb bud presumptive chondroblasts by a temperature-sensitive mutant of Rous sarcoma virus and the reversible inhibition of their terminal differentiation in culture.

Stage 21 to 22 chicken embryo limb bud cells were infected with a temperature-sensitive mutant of Rous sarcoma virus and were grown in culture. Although control, uninfected cells yielded definitive chondroblasts (by day 4) which initiated the synthesis of the cartilage-characteristic proteoglycan, the transformed cells grown at the permissive temperature failed to do so. These effects were fully reversible after a shift to the nonpermissive temperature. In addition, infected cells at the nonpermissive temperature expressed traits of terminal chondrogenic maturation 2 to 3 days earlier than parallel, uninfected cells. Thus, Rous sarcoma virus-induced transformation reversibly blocks terminal limb bud cell chondrogenesis in culture, at the nonpermissive temperature, viral infection may also induce intracellular or extracellular conditions which favor or accelerate the process of chondrogenic cell maturation.