Functional analysis of the vaccinia virus entry protein L1 / Chwan Hong Foo.

Format:

Book

Manuscript

Thesis/Dissertation

Author/Creator:

Foo, Chwan Hong.

Contributor:

Cohen, Gary H., advisor.

Eisenberg, Roselyn J., advisor.

University of Pennsylvania.

Language:

English

Subjects (All):

Penn dissertations--Cell and molecular biology.

Cell and molecular biology--Penn dissertations.

Cell and Molecular Biology.

Academic Dissertations as Topic.

Medical Subjects:

Cell and Molecular Biology.

Academic Dissertations as Topic.

Local Subjects:

Penn dissertations--Cell and molecular biology.

Cell and molecular biology--Penn dissertations.

Physical Description:

xiii, 309 pages : illustrations (some color) ; 29 cm

Production:

2010.

Summary:

Vaccinia virus (VACV) L1 is a myristoylated envelope protein which is required for ceL1 entry and low-pH-triggered fusion of virus infected cells. L1 also associates with members of the poxvirus entry-fusion complex (EFC), but is not required for the assembly or stability of the core complex. Despite some recent progress, the specific function(s) of L1 during entry remain poorly defined. It is currently unclear if L1 functions during or prior to membrane fusion, such as attaching to cell surface molecules. In addition, the host cell receptor(s) responsible for triggering internalization and/or membrane fusion of VACV have not been identified.

In this dissertation, I present my efforts to identify the specific role that L1 plays in entry and to characterize the regions on this protein which are important for its function. In the first chapter of this dissertation, I show that a recombinant form of the L1 ectodomain binds to cell surfaces and inhibits entry of VACV independently of glycosaminoglycans. These observations suggest that L1 is a viable candidate for the VACV receptor-binding protein. In the second chapter of this dissertation, I engineered six L1 mutants which are defective in complementation and/or N-myristoylation. I demonstrate that two acylated L1 mutants which are impaired in complementation are properly incorporated into mature virions. These results indicate that the conserved amino terminus of L1 is important for its myristoylation and for VACV entry. In the third chapter of this dissertation, I performed truncations and a deletion in the conserved C-terminal endodomain of L1. I discovered that several components of the poxvirus EFC do not interact with the truncated mutants, providing the first evidence that the endodomain of L1 is required for EFC association. I also found that a L1 mutant with a two residue deletion in its endodomain associates normally with EFC proteins and is packaged into mature virions, yet it does not function in entry. These observations indicate that the endodomain of L1 is a critical functional region required for EFC association and for virus entry.

Notes:

Advisers: Gary H. Cohen; Roselyn J. Eisenberg.

Thesis (Ph.D. in Cell and Molecular Biology) -- University of Pennsylvania, 2010.

Includes bibliographical references.