Leonard Norkin

Professor Emeritus

Photo of Leonard Norkin



Columbia University, New York, NY, 1969

Mailing address: 

Leonard C. Norkin, Ph.D.
Department of Microbiology
418 Morrill Science Center IVN
University of Massachusetts
639 North Pleasant Street
Amherst, MA 01003-9298

Research Interests

My main research goal was to characterize the entry pathway of simian virus 40 (SV40) into host cells. Key findings of my group included the following. First, SV40 enters cells via caveola-mediated endocytosis. Indeed, ours was the first demonstration that an intracellular microbial pathogen might invade cells via this means. The atypical caveola-mediated SV40 entry pathway then delivers the virus to the endoplasmic reticulum; a rather unusual site for cargo taken up by endocytosis. Next, we established that the virus begins to disassemble in the ER, as shown by our finding that its internal capsid proteins first become accessible to immunofluorescent detection in that organelle. The virus is then released from the ER into the cytoplasm, where it undergoes further disassembly that exposes its BrdU-labelled genomic DNA to detection by anti-BrdU antibodies. The cytoplasmic, partially disassembled SV40 particles still retain some of the SV40 capsid proteins, VP1, VP2, and VP3, in addition to the viral genome. Most recently we found that the SV40 genome entirely disassociates from its capsid proteins before or at the point of entry into the nucleus, and then enters the nucleus devoid of those proteins. I recently authored a virology textbook (Virology: Molecular Biology and Pathogenesis by Leonard C. Norkin, ASM Press, 2010), and served as Chairperson of the Polyomavirus Study Group of the International Committee on the Taxonomy of Viruses (ICTV).

Selected Publications

Research interests - short: 

Professor Emeritus