Ying Fang

Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)

Department / School

Biology and Microbiology


The nucleocapsid (N) protein of porcine reproductive and respiratory syndrome virus is a 123 amino acid structural protein required for packaging the single stranded RNA genome. In addition to its structural function, we propose that the N protein is also involved in regulation of host cell function during replication. Using enhanced green fluorescent protein as a tag, we identified a highly conserved basic region (residues 43- 60) which is required for N protein nucleolar localization and is capable of directing the nuclear and nucleolar translocation of an otherwise cytoplasmic protein, ~ - galactosidase. Mutation analysis showed that the basic residues Lysine 43 and Lysine 44 are critical for nucleolar targeting of the N protein. N protein nuclear import was enhanced by modifying the phosphorylation of two CK-II sites (threonine 59 and threonine 68). These results demonstrate that N protein contains a functional nucleolar localization signal sequence (residues 43-60) which directs N protein to the cell nucleolus and suggest that CK-II phosphorylation plays a role in the regulation of N protein nucleolar localization.

Library of Congress Subject Headings

Swine -- Virus diseases
Porcine reproductive and respiratory syndrome

Number of Pages