A retroviral myc gene induces preneoplastic transformation of lymphocytes in a bursal transplantation assay.
Treatment of chicken embryos with cyclophosphamide results in ablation of bursal lymphocytes. Bursal follicles can be reconstructed by infusion of embryonic bursal cells. Histologic examination of reconstituting bursal follicles showed that the first lymphocytes to appear were large pyrinophilic lymphoblasts that lined up adjacent to the bursal basement membrane and appeared to serve as progenitors for the differentiation of bursal medullary lymphocytes. When these cells were infected with the avian myelocytomatosis virus HB1 bearing a v-myc oncogene they appeared to home to the region of the bursal basement membrane but failed to differentiate. Instead, they formed structures indistinguishable from the preneoplastic transformed follicles that develop during bursal lymphomagenesis induced by lymphoid leukosis viruses. The DNA from these transformed follicles contained the HB1 v-myc gene but lacked the ability to transform NIH/3T3 mouse cells. Therefore these preneoplastic lesions were induced directly by HB1 myc and did not require the expression of Blym-1 or similar oncogenes. Exploitation of this transplantation technique with the chicken bursa will provide a useful method for assessing the stage-specific activity of oncogenes in vivo.
D000818:Animals; D002060:Bursa of Fabricius / Q000382:microbiology* / Q000473:pathology / Q000637:transplantation; D002472:Cell Transformation, Viral; D002478:Cells, Cultured; D005814:Genes, Viral; D008214:Lymphocytes / Q000382:microbiology*; D008223:Lymphoma / Q000382:microbiology; D051379:Mice; D009857:Oncogenes; D011230:Precancerous Conditions / Q000382:microbiology*; D012190:Retroviridae / Q000235:genetics*