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Identification of the NLS and NES motifs of VP2 from chicken anemia virus and the interaction of VP2 with mini-chromosome maintenance protein 3.

Cheng JH, Sheu SC, Lien YY, Lee MS, Chen HJ, Su WH, Lee MS - BMC Vet. Res. (2012)

Bottom Line: A NES is also predicted in VP2; however the results suggest that no functional NES is present and that this protein is CRM1 independent.It was also shown that VP2 is a chromatin binding protein and, notably, using a co-immunoprecipitation assay, it was found that VP2 association with MCM3 and that this interaction does not require DSP activity.VP2 is a CRM1 independent protein during nuclear export and associates with MCM3 in cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Medical Research, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan.

ABSTRACT

Background: VP2 of chicken anemia virus (CAV) is a dual-specificity phosphatase required for virus infection, assembly and replication. The functions of the nuclear localization signal (NLS) and nuclear export signal (NES) of VP2 in the cell, however, are poorly understood. Our study identified the presence of a NLS in VP2 and showed that the protein interacted significantly with mini-chromosome maintenance protein 3 (MCM3) in the cell.

Results: An arginine-lysine rich NLS could be predicted by software and spanned from amino acids 133 to 138 of VP2. The critical amino acids residues between positions 136 and 138, and either residue 133 or 134 are important for nuclear import in mammalian cells based on systematic mutagenesis. A NES is also predicted in VP2; however the results suggest that no functional NES is present and that this protein is CRM1 independent. It was also shown that VP2 is a chromatin binding protein and, notably, using a co-immunoprecipitation assay, it was found that VP2 association with MCM3 and that this interaction does not require DSP activity.

Conclusions: VP2 contains a NLS that span from amino acids 133 to 138. VP2 is a CRM1 independent protein during nuclear export and associates with MCM3 in cells.

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Related in: MedlinePlus

Analysis and predication of NLS and NES motifs present in the VP2 amino acid sequence. The various VP2 amino acid sequences (51 to 200) from different CAV isolates were aligned as described in the Materials and Methods. The putative NLS motifs (BiNLS1: under line and NLS2: bold words) and NES motifs (under line, bold, shadow and Italic) are shown. The cysteine residues at positions 95 and 97 in the catalytic motif of VP2 are also indicated by an arrow and an arrow head, respectively
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Figure 2: Analysis and predication of NLS and NES motifs present in the VP2 amino acid sequence. The various VP2 amino acid sequences (51 to 200) from different CAV isolates were aligned as described in the Materials and Methods. The putative NLS motifs (BiNLS1: under line and NLS2: bold words) and NES motifs (under line, bold, shadow and Italic) are shown. The cysteine residues at positions 95 and 97 in the catalytic motif of VP2 are also indicated by an arrow and an arrow head, respectively

Mentions: In order to identify if there are any NLS or NES motifs in VP2, we first compared the amino acid sequence of VP2 (Taiwan CIA-89) with a range of other CAV isolates to explore the protein's sequence divergence. The various VP2 sequences of the different CAV isolates were obtained from the UniProtKB database (http://www.uniprot.org/). Based on the sequence alignment, the VP2 proteins of these CAV isolates are highly conserved compared to strain CIA-89 from Taiwan. Therefore, the full length of amino acid sequence of VP2 (Taiwan CIA-89) was used and examined in order to predict NLS sequences using the WoLF PSORT and NLStradamus programs (Figures 2 and 3A). A bipartite NLS motif (named BiNLS1) was predicted by the WoLF PSORT program, with the putative motif position spanned amino acid residues from 136 to 153 (under line). However, a monopartite NLS motif (named NLS2) was also predicted by NLStradamus at a prediction cutoff value at 0.5 and this motif was located from amino acid residues from 133 to 138 (bold). Based on the results of bioinformatics analysis, VP2 was predicted to containing two possible NLS motifs. In addition, the NES motif prediction was performed by NetNES 1.1 Server (Figures 2 and 3A). A putative NES from amino acid residues 120 to 128 (under line, bold, shadow and Italic) was pinpointed. However, the expected value for NES prediction was lower than threshold expected value of this program, which suggests that there is a low probability of a NES motif existing within VP2. Based on these results, further investigations were needed to elucidate whether or not a NES is functional in VP2.


Identification of the NLS and NES motifs of VP2 from chicken anemia virus and the interaction of VP2 with mini-chromosome maintenance protein 3.

Cheng JH, Sheu SC, Lien YY, Lee MS, Chen HJ, Su WH, Lee MS - BMC Vet. Res. (2012)

Analysis and predication of NLS and NES motifs present in the VP2 amino acid sequence. The various VP2 amino acid sequences (51 to 200) from different CAV isolates were aligned as described in the Materials and Methods. The putative NLS motifs (BiNLS1: under line and NLS2: bold words) and NES motifs (under line, bold, shadow and Italic) are shown. The cysteine residues at positions 95 and 97 in the catalytic motif of VP2 are also indicated by an arrow and an arrow head, respectively
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3295642&req=5

Figure 2: Analysis and predication of NLS and NES motifs present in the VP2 amino acid sequence. The various VP2 amino acid sequences (51 to 200) from different CAV isolates were aligned as described in the Materials and Methods. The putative NLS motifs (BiNLS1: under line and NLS2: bold words) and NES motifs (under line, bold, shadow and Italic) are shown. The cysteine residues at positions 95 and 97 in the catalytic motif of VP2 are also indicated by an arrow and an arrow head, respectively
Mentions: In order to identify if there are any NLS or NES motifs in VP2, we first compared the amino acid sequence of VP2 (Taiwan CIA-89) with a range of other CAV isolates to explore the protein's sequence divergence. The various VP2 sequences of the different CAV isolates were obtained from the UniProtKB database (http://www.uniprot.org/). Based on the sequence alignment, the VP2 proteins of these CAV isolates are highly conserved compared to strain CIA-89 from Taiwan. Therefore, the full length of amino acid sequence of VP2 (Taiwan CIA-89) was used and examined in order to predict NLS sequences using the WoLF PSORT and NLStradamus programs (Figures 2 and 3A). A bipartite NLS motif (named BiNLS1) was predicted by the WoLF PSORT program, with the putative motif position spanned amino acid residues from 136 to 153 (under line). However, a monopartite NLS motif (named NLS2) was also predicted by NLStradamus at a prediction cutoff value at 0.5 and this motif was located from amino acid residues from 133 to 138 (bold). Based on the results of bioinformatics analysis, VP2 was predicted to containing two possible NLS motifs. In addition, the NES motif prediction was performed by NetNES 1.1 Server (Figures 2 and 3A). A putative NES from amino acid residues 120 to 128 (under line, bold, shadow and Italic) was pinpointed. However, the expected value for NES prediction was lower than threshold expected value of this program, which suggests that there is a low probability of a NES motif existing within VP2. Based on these results, further investigations were needed to elucidate whether or not a NES is functional in VP2.

Bottom Line: A NES is also predicted in VP2; however the results suggest that no functional NES is present and that this protein is CRM1 independent.It was also shown that VP2 is a chromatin binding protein and, notably, using a co-immunoprecipitation assay, it was found that VP2 association with MCM3 and that this interaction does not require DSP activity.VP2 is a CRM1 independent protein during nuclear export and associates with MCM3 in cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Medical Research, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan.

ABSTRACT

Background: VP2 of chicken anemia virus (CAV) is a dual-specificity phosphatase required for virus infection, assembly and replication. The functions of the nuclear localization signal (NLS) and nuclear export signal (NES) of VP2 in the cell, however, are poorly understood. Our study identified the presence of a NLS in VP2 and showed that the protein interacted significantly with mini-chromosome maintenance protein 3 (MCM3) in the cell.

Results: An arginine-lysine rich NLS could be predicted by software and spanned from amino acids 133 to 138 of VP2. The critical amino acids residues between positions 136 and 138, and either residue 133 or 134 are important for nuclear import in mammalian cells based on systematic mutagenesis. A NES is also predicted in VP2; however the results suggest that no functional NES is present and that this protein is CRM1 independent. It was also shown that VP2 is a chromatin binding protein and, notably, using a co-immunoprecipitation assay, it was found that VP2 association with MCM3 and that this interaction does not require DSP activity.

Conclusions: VP2 contains a NLS that span from amino acids 133 to 138. VP2 is a CRM1 independent protein during nuclear export and associates with MCM3 in cells.

Show MeSH
Related in: MedlinePlus