Transient replication assays have identified a late expression factor 3, LEF-3, to be essential for DNA replication and late gene expression in the baculovirus species, AcMNPV. Although its specific role in these two processes has not been determined, this single-stranded DNA binding protein is multi-functional. LEF-3 forms a homo-oligomer, binds single-stranded DNA, interacts with components of the viral replication complex and is required to transport the helicase protein P143 into the nucleus of infected cells. Various regions within LEF-3 were deleted to determine the domain essential to its function and the N-terminal amino acids 1-125 were found to be sufficient for late gene expression. This N-terminal region includes the 56 amino acid region of LEF-3 required for nuclear transport. In order to define this domain, the effect of site-specific mutagenesis of LEF-3 on its intracellular distribution was determined. Fluorescence microscopy of expression plasmid transfected cells demonstrated that amino acids 14 to 37 formed the core nuclear localization signal (NLS), but the flanking amino acids may act as regulatory elements. Comparison with other group 1 Alphabaculoviruses suggested that this core region contained a functionally duplicated NLS. The AcMNPV LEF-3 also functioned in mammalian cells indicating that the protein nuclear import systems in insect and mammalian cells are conserved. Mutagenesis of two conserved cysteine residues located at amino acids 82 and 106 were not essential for nuclear localization or for interaction with P143. However, by using a modified construct of P143 that localized on its own to the nucleus, it was demonstrated that a functional nuclear localization domain on LEF-3 was required for an interaction between LEF-3 and P143. / Thesis (Master, Microbiology & Immunology) -- Queen's University, 2009-01-04 18:25:23.7

Thesis (Ph. D. in Biochemistry)--Vanderbilt University, Aug. 2008. / Title from title screen. Includes bibliographical references.

Thesis (Ph. D.)--Northeastern University, 2008. / Title from title page (viewed March 27, 2009). Graduate School of Arts and Sciences, Dept. of Physics. Includes bibliographical references (p. 130-157).

Thesis (Ph. D.)--University of Virginia, 1998. / Spine title: Study of DHFR DNA replication origin. Includes bibliographical references (p. 152-168). Also available online through Digital Dissertations.

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2004. / Includes bibliographical references (leaves 83-100). Also available in electronic version. Access restricted to campus users.

Thesis (M.S.)--University of Toledo, 2004. / Typescript. "A thesis [submitted] as partial fulfillment of the requirements of the Master of Science degree in Chemistry." Bibliography: leaves 111-112.

Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2002. / Includes bibliographical references (leaves 74-80). Also available in electronic version. Access restricted to campus users.

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 96-116). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--University of Texas at Austin, 2005. / Supervisor: Kenneth A. Johnson. Vita. Includes bibliographical references.

Thesis (Ph.D.)--University of Delaware, 2005. / Principal faculty advisor: Simmons, Daniel T., Dept. of Biological Sciences. Includes bibliographical references.