Until her retirement and appointment as Scientist Emerita in 2015, Dr. Judith G. Levin was formerly Head, Section on Viral Gene Regulation, Program in Genomics of Differentiation (now the Division of Developmental Biology), Eunice Kennedy Shriver National Institute of Child Health and Human Development. She received a B.A. degree in Chemistry from Barnard College, an M.A. degree in Biochemistry from Harvard University, and a Ph.D. degree in Biochemistry from Columbia University. She has spent her entire professional career at the NIH, coming initially to work as a postdoctoral fellow in the laboratory of Dr. Marshall Nirenberg, where she performed studies on protein synthesis and the genetic code. Since the 1970s, Dr. Levin has been investigating the molecular mechanisms involved in retrovirus replication. In her early work, she studied murine leukemia virus (MLV) replication and made several novel discoveries: (i) MLV assembly proceeds in the absence of viral genomic RNA, although virions contain the full complement of viral proteins; (ii) MLV-infected cells contain two non-equilibrating pools of full-length viral RNA, one for encapsidation (short-lived) and the other functioning as the mRNA for the Gag precursor (long-lived), which rationalizes the earlier observation; and (iii) A series of papers defining the unique mechanism for MLV translational read-through suppression, which is required for synthesis of the Pol proteins, protease, reverse transcriptase, and integrase.
The figure shows a schematic representation of the structure of the mature HIV-1 virion (courtesy of Dr. Louis E. Henderson, AIDS Vaccine Program, SAIC Frederick, Inc.). Abbreviations for viral proteins: MA, matrix; CA, capsid; NC, nucleocapsid; PR, protease; RT, reverse transcriptase; IN, integrase; SU, surface glycoprotein; TM, transmembrane. HLA I and HLA II, DR refer to host histocompatibility proteins selectively incorporated into the virion. Note the characteristic cone-shaped core.