Arnold Berk is Professor of Microbiology, Immunology and Molecular Genetics and a member of the Molecular Biology Institute at the University of California, Los Angeles. Dr. Berk is also a fellow of the American Academy of Arts and Sciences. He is one of the original discoverers of RNA splicing and of mechanisms for gene control in viruses. His laboratory studies the molecular interactions that regulate transcription nitiation in mammalian cells, focusing particular attention on transcription factors encoded by oncogenes and tumor suppressors. He teaches introductory courses in molecular biology and virology and an advanced course in cell biology of the nucleus.