A domain of SV40 capsid polypeptide VP1 that specifies migration into the cell nucleus.

Abstract

In order to identify the determinants responsible for the nuclear migration of simian virus 40 (SV40) polypeptide VP1, the 5′‐terminal portion of the SV40 VP1 gene was fused with the complete cDNA sequence of poliovirus capsid polypeptide VP1 and the hybrid gene was inserted into an SV40 vector in place of the normal SV40 VP1 gene. Deletions of various length were generated in the SV40 VP1 portion of the hybrid gene, resulting in a set of truncated genes encoding 2‐40 NH2‐terminal amino acids from SV40 VP1, followed by poliovirus VP1. Monkey kidney cells were infected by the deleted hybrid viruses in the presence of an early SV40 amber mutant as helper, and the subcellular localization of the fusion proteins was determined by indirect immunofluorescence using an anti‐poliovirus VP1 immune serum. The presence of the first 11 NH2‐terminal amino acids from SV40 VP1 was found to be sufficient to target the fusion protein to the cell nucleus. Deletions extending from the NH2‐ towards the COOH‐terminal end of the protein were next generated. Transport of the SV40 VP1‐poliovirus VP1 fusion polypeptide to the nucleus was abolished when the first eight amino acids from SV40 VP1 were deleted. Thus the sequence of the first eight NH2‐terminal amino acids of SV40 VP1 appears to contain a nuclear migration signal which is sufficient to target the protein to the cell nucleus.

SNF6 encodes a nuclear protein that is required for expression of many genes in Saccharomyces cerevisiae.

“…Homology of SNF6 sequence to nuclear localization signals. The SNF6 sequence from amino acids 2 to 10 is compared with sequences that have been identified as nuclear localization determinants in the simian virus 40 (SV40) large T antigen (20)(21)(22); polyomavirus large T antigen (33); simian virus 40 VP1 protein (43); and Xenopus oocyte nucleoplasmin (6). Numbers at the left indicate the position of the first residue shown.…”

Association with capsid proteins promotes nuclear targeting of simian virus 40 DNA.

“…The viral proteins require independent karyophilic property and DNA interactive capability that are represented as an NTS and a DNA-binding domain, respectively. All SV40 structural proteins are sequence-nonspecific DNA-binding proteins (33,43) and carry an individual NTS (13)(14)(15) (46), implying that different structural proteins play a role in the DNA nuclear targeting of the two related viruses. How the antibodies introduced into the cytoplasm act to intercept T-antigen expression is not known at this time.…”

“…Adenovirus appears to release the viral DNA into the nucleus together with the hexon, but not with many other viral proteins (3,4). In retrovirus (5,6), influenza virus (7-9), hepadnavirus (10), hepatitis delta virus (11), adenovirus (12), and papovavirus (13)(14)(15)(16)(17)(18), many structural and virion-associated proteins have been found to harbor nuclear-targeting signals (NTSs). These results are consistent with the idea that the NTSs of viral structural proteins or/and virion-associated proteins are responsible for the nuclear entry of the viral genome.…”

“…such inhibitors as wheat germ agglutinin and anti-nucleoporin antibody (21). During a productive infection cycle, the viral structural proteins, Vpl, Vp2, and Vp3, localize to the nucleus (24) through the NPC by virtue of their individual NTSs, which have been identified (13)(14)(15). The karyophilic histones, some of whose NTSs are known (25,26), also enter the nucleus through the NPC (27)(28)(29).…”

Analysis of the L1 Gene Product of Human Papillomavirus Type 16 by Expression in a Vaccinia Virus Recombinant

“…Putative nuclear migration signals have been identified in the simian virus (SV) 40 T antigen (Kalderon et al, 1984), polyoma virus T antigen (Richardson et al, 1986), the yeast match2 protein (Hall et al, 1984) and in the human oestradiol receptor (Green et al, 1986). In addition, studies with SV40 capsid polypeptides VP1 (Wychowski et al, 1986) indicate that the sequence of the first eight Nterminal amino acids of VP1 appear to contain a nuclear migration signal that is sufficient to target the protein to the cell nucleus. All potential nuclear localization sequences identified to date appear to consist of clusters of basic amino acids, e.g.…”