Insertion of SMRV‐H viral DNA at the c‐myc gene locus of a BL cell line and presence in established cell lines

Abstract

Mutation of the c‐myc gene locus has occurred during in vitro culture of the Burkitt lymphoma cell line Namalwa. Gene cloning and sequencing of this c‐myc gene locus has revealed the insertion of incomplete copies of the Squirrel Monkey Retrovirus‐Human (SMRV‐H) proviral genome. Insertions of the SMRV‐H genome were seen in all Namalwa cell lines tested, with multiple insertions being seen in some sublines. Viral particles with the morphology of type‐D retrovirus, budding from these cells, were seen by transmission EM. New insertions of the genome were produced spontaneously in these cells. The origins of the type‐D retrovirus and its implications for workers in the field are discussed.