DESCRIPTION (provided by applicant): The mechanisms by which foreign DNAs enter mitochondria are largely unknown. The goal of the proposed studies is to develop an in vitro model for study of uptake, replication and transcription of foreign DNA by mitochondria. This cell culture based model system will take advantage of a unique virus-like agent which infects and replicates in the mitochondria of tumor cells in a tropical marine fish, the bicolor damselfish (Stegastes partitus). This transmissible agent (DVLA) is associated with the naturally occurring, infectious disease termed damselfish neurofibromatosis. DVLA does not resemble any known family of virus or viroid. The unusual sequence and secondary structure of the DNA genome of this agent are likely a direct result of the apparently unique life-style of this agent and may provide clues to optimizing uptake and processing of foreign DNA by mitochondria. The aims of the proposed study are to examine the entry of DVLA DNA into isolated mitochondria and evaluate the replication and transcription of this DNA in the mitochondria. This is a high risk research project with the potential to yield data which should be widely applicable to understanding pathogenesis in mitochondria and for development of techniques for mitochondrial transgenesis in other vertebrates.