Nucleolar localization of non-structural protein 3b, a protein specifically encoded by the severe acute respiratory syndrome coronavirus

• Published in: Virus research Vol. 114; no. 1; pp. 70 - 79
• Main Authors: Yuan, Xiaoling, Yao, Zhenyu, Shan, Yajun, Chen, Bo, Yang, Zhen, Wu, Jie, Zhao, Zhenhu, Chen, Jiapei, Cong, Yuwen
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-12-2005
• Subjects: Amino Acid Sequence; Animals; Cell Line; Cell Nucleolus - metabolism; Chlorocebus aethiops; Chromosomal Proteins, Non-Histone - metabolism; COS Cells; Green Fluorescent Proteins - genetics; Green Fluorescent Proteins - metabolism; Humans; Nuclear Proteins - metabolism; Nucleolin; Nucleophosmin; Phosphoproteins - metabolism; Protein Sorting Signals; RNA-Binding Proteins - metabolism; SARS coronavirus; Severe acute respiratory syndrome-related coronavirus - genetics; Severe acute respiratory syndrome-related coronavirus - metabolism; Severe acute respiratory syndrome-related coronavirus - pathogenicity; Transfection; Vero Cells; Viral Nonstructural Proteins - chemistry; Viral Nonstructural Proteins - genetics; Viral Nonstructural Proteins - metabolism; PBS; DMEM; ORF; NLS; SARS-CoV; SARS; EGFP; NoLS; N; ECL
• ISSN: 0168-1702; 1872-7492
• DOI: 10.1016/j.virusres.2005.06.001

The open reading frame 3 (ORF3) of the severe acute respiratory syndrome coronavirus (SARS-CoV) genome encodes a predicted 154-amino acid protein, which lacks similarities to any known protein, and is named 3b. In this study, it was shown that 3b protein was predominately localized to nucleus with EGFP tag at its N- or C-terminus. The localization patterns were similar in different transfected cells. Immuno-fluorescence assay revealed that 3b protein was co-localized well with C23 in nucleolus. C23, B23 and fibrillarin all are important nucleolar proteins, which localize in the region of the nucleolus. Co-transfection of p3b-EGFP with pC23-DsRed, pB23-DsRed and pfibrillarin-DsRed further confirmed 3b's nucleolus localization. With construction of serial truncated mutants of 3b, a region (residues 134–154 aa) responsible for nucleolar localization was determinated in 3b protein. These results provide a new insight for further functional studies of SARS-CoV 3b protein.