Retroviruses have been of great importance to biomedical science for the past half century. Initially, studies on oncogenic animal retroviruses provided important insights into molecular processes in carcinogenesis – most notably the existence and mechanisms of action of oncogenes and proto-oncogenes. Moreover, several human diseases are caused by retroviruses, including AIDS, adult T-cell leukemia and the neurological disease HAM/TSP. The topic of this volume is a relatively unknown animal retrovirus, jaagsiekte sheep retrovirus, the causative agent of transmissible lung cancer in sheep –ovine pulmonary adenocarcinoma. The disease was first documented in South Africa in the 1800s, it has a wide geographical distribution, and it is of economic importance in high endemic regions. However, until very recently the nature of the etiologic agent was unclear, and relatively few laboratories actively studied the disease.

This book will contain a series of review articles that focus on retroviral models of human and animal cancers. Each article will be written by an expert in the field of retrovirology. The reviews will summarize current work on a particular retrovirus, with particular emphasis on the relevance of this research to human disease.

For over 25 years the study of retroviruses has underpinned much of what is known about information transfer in cells and the genetic and biochemical mechanisms that underlie cell growth and cancer induction. Emergent diseases such as AIDS and adult T-cell lymphoma have widened even further the community of investigators directly concerned with retroviruses, a development that has highlighted the need for an integrated understanding of their biology and their unique association with host genomes. This remarkable volume satisfies that need. Written by a group of the field's most distinguished investigators, rigorously edited to provide a seamless narrative, and elegantly designed for clarity and readability, this book is an instant classic that demands attention from scientists and physicians studying retroviruses and the disorders in which they play a role.

Approximately eight percent of our DNA contains retroviral sequences that are millions of years old. Through engaging stories of scientific discovery, Anna Marie Skalka explains our evolving knowledge of these ancient denizens of the biosphere and how this understanding has significantly advanced research in genetic engineering, gene delivery systems, and precision medicine. Discovering Retroviruses begins with the pioneer scientists who first encountered these RNA-containing viruses and solved the mystery of their reproduction. Like other viruses, retroviruses invade the cells of a host organism to reproduce. What makes them “retro” is a unique process of genetic information transfer. Instead of transcribing DNA into RNA as all living cells do, they transcribe their RNA into DNA. This viral DNA is then spliced into the host’s genome, where the cell’s synthetic machinery is co-opted to make new virus particles. The 100,000 pieces of retroviral DNA in the human genome are remnants from multiple invasions of our ancestors’ “germline” cells—the cells that allow a host organism to reproduce. Most of these bits of retroviral DNA are degenerated fossils, but some have been exploited during evolution, with profound effects on our physiology. Some present-day circulating retroviruses cause cancers in humans and other animals. Others, like HIV, cause severe immunodeficiencies. But retroviruses also hold clues to innovative approaches that can prevent and treat these diseases. In laboratories around the world, retroviruses continue to shed light on future possibilities that are anything but “retro.”

Leading scientists in the field review the genomics, molecular biology and pathogenesis of these important viruses, comprehensively covering all the recent advances.

Is cancer a contagious disease? In the late nineteenth century this idea, and attending efforts to identify a cancer “germ,” inspired fear and ignited controversy. Yet speculation that cancer might be contagious also contained a kernel of hope that the strategies used against infectious diseases, especially vaccination, might be able to subdue this dread disease. Today, nearly one in six cancers are thought to have an infectious cause, but the path to that understanding was twisting and turbulent. ​ A Contagious Cause is the first book to trace the century-long hunt for a human cancer virus in America, an effort whose scale exceeded that of the Human Genome Project. The government’s campaign merged the worlds of molecular biology, public health, and military planning in the name of translating laboratory discoveries into useful medical therapies. However, its expansion into biomedical research sparked fierce conflict. Many biologists dismissed the suggestion that research should be planned and the idea of curing cancer by a vaccine or any other means as unrealistic, if not dangerous. Although the American hunt was ultimately fruitless, this effort nonetheless profoundly shaped our understanding of life at its most fundamental levels. A Contagious Cause links laboratory and legislature as has rarely been done before, creating a new chapter in the histories of science and American politics.

Methods included in this volume apply to the expression and characterization of retroviral proteases and their inhibitor/substrate design.