Sidney Farber Cancer Institute, 44 Binney Street. Boston. Ma 02115 USA

Introduction

Comparative structural analysis of RNA tumor virus genomes is relevant to several questions regarding the biology of these viruses and their role in neoplastic disease. We have recently developed and applied procedures that facilitate such studies. Using these methods we have studied murine, primate, feline and avian C-type viruses. In some cases our studies permit direct comparison of the nucleotide sequence. The questions investigated that will be discussed here include: 1. The relationship amongst viruses isolated from the AKR mouse. Viruses that differ in oncogenic potency and in host range have been isolated from the tissues of AKR mice. A comparison of the structure of the Akv virus, an ecotropic N-tropic virus that forms plaques in the XC test (XC+) with that of a xenotropic AKR virus is presented. The structure of an ecotropic, N-tropic XC- virus produced by lymphoid cell lines established from spontaneous AKR thymomas is also described. These studies structurally define anew class of AKR virus. 2. The sequence relationship amongst primate viruses of the woolly-gibbon group. Analysis of the structure offour independent isolates of gibbon ape Ctype viruses and an isolate from a woolly monkey are presented. The structure of a virus isolated from a patient with acute myelogenous leukemia (HL23) that has previously been shown to be related to the woolly monkey isolate is also investigated. 3. The sequence relationships among viruses of the feline leukosis group (FeLV): This work shows that these isolates are very closely related; the sequence ofat least half the genome is identical. 4. The relationships between the transformation defective and non-defective Rous Sarcoma virus PrB is investigated. Sequence information of portions of the genome that code for the transformation function and for the structural genes is presented.