scholarly journals Maize Streak Virus Coat Protein Is Karyophyllic and Facilitates Nuclear Transport of Viral DNA

1999 ◽  
Vol 12 (10) ◽  
pp. 894-900 ◽  
Author(s):  
H. Liu ◽  
M. I. Boulton ◽  
C. L. Thomas ◽  
D. A. M. Prior ◽  
K. J. Oparka ◽  
...  
Keyword(s):  
Coat Protein ◽  
Nuclear Transport ◽  
Transient Gene Expression ◽  
Maize Streak Virus ◽  
Host Cells ◽  
Immunofluorescent Staining ◽  
Vector System ◽  
Viral Gene ◽  
Streak Virus ◽  
Viral Dna

Transport of maize streak virus (MSV) DNA into the nucleus of host cells is essential for virus replication and the presence of virus particles in the nuclei of infected cells implies that coat protein (CP) must enter the nucleus. To see if CP is imported into the nucleus in the absence of other viral gene products, the MSV CP gene was expressed in insect cells with a baculovirus vector system, and also in tobacco protoplasts with a cauliflower mosaic virus (CaMV) 35S promoter-driven transient gene expression vector. Immunofluorescent staining showed that the CP accumulated in the nuclei of both insect and tobacco cells. Mutagenesis of a potential nuclear localization signal in the CP resulted in cytoplasmic accumulation of the mutant protein. We have shown previously that the CP binds to single-stranded (ss) and double-stranded (ds) viral DNA. To investigate if CP might also be involved in viral DNA nuclear transport, Escherichia coli-expressed CP, together with TOTO-1-labeled viral ss or ds DNA, was microinjected into maize and tobacco epidermal cells. Both ss and ds DNA moved into the nucleus when co-injected with the CP but not with E. coli proteins alone. These results suggest that, in addition to entering the nucleus where it is required for encapsidation of the viral ss DNA, the MSV CP facilitates the rapid transport of viral (ss or ds) DNA into the nucleus.

scholarly journals Bidirectional transcription of maize streak virus DNA and identification of the coat protein gene

1985 ◽  
Vol 13 (20) ◽  
pp. 7237-7256 ◽  
Author(s):  
Bret A.M. Morris-Krsinich ◽  
Philip M. Mullineaux ◽  
Jonathan Donson ◽  
Margaret I. Boulton ◽  
Peter G. Markham ◽  
...  
Keyword(s):  
Coat Protein ◽  
Coat Protein Gene ◽  
Protein Gene ◽  
Maize Streak Virus ◽  
Streak Virus ◽  
Bidirectional Transcription

scholarly journals Insect High FiveTM cell line development using site-specific flipase recombination technology

2021 ◽  
Author(s):  
Mafalda M Dias ◽  
João Vidigal ◽  
Daniela P Sequeira ◽  
Paula M Alves ◽  
Ana P Teixeira ◽  
...  
Keyword(s):  
Cell Line ◽  
Trichoplusia Ni ◽  
Scale Up ◽  
Transient Gene Expression ◽  
Suspension Cultures ◽  
Host Cells ◽  
Vector System ◽  
Small Scale ◽  
Heterologous Proteins ◽  
Protein Model

Abstract Insect Trichoplusia ni High FiveTM (Hi5) cells have been widely explored for production of heterologous proteins, traditionally mostly using the lytic baculovirus expression vector system (BEVS), and more recently using virus-free transient gene expression systems. Stable expression in such host cells would circumvent the drawbacks associated with both systems when it comes to scale-up and implementation of more efficient high-cell density process modes for the manufacturing of biologics. In this work, we combined Flipase (Flp) recombinase-mediated cassette exchange (RMCE) with fluorescence-activated cell sorting (FACS) for generating a stable master clonal Hi5 cell line with the flexibility to express single or multiple proteins of interest from a tagged genomic locus. The 3-step protocol herein implemented consisted of (i) introducing the RMCE docking cassette into the cell genome by random integration followed by selection in Hygromycin B and FACS (Hi5-tagging population), (ii) eliminating cells tagged in loci with low recombination efficiency by transfecting the tagging population with an eGFP-containing target cassette followed by selection in G418 and FACS (Hi5-RMCE population), and (iii) isolation of pure eGFP-expressing cells by FACS and expansion to suspension cultures (Hi5-RMCE master clone). Exchangeability of the locus in the master clone was demonstrated in small-scale suspension cultures by replacing the target cassette by one containing a single protein (i.e. iCherry, as an intracellular protein model) or two proteins (i.e. influenza HA and M1 for virus-like particles production, as an extracellular protein model). Overall, the stable insect Hi5 cell platform herein assembled has the potential to assist and accelerate biologics development.

scholarly journals Interaction of the movement and coat proteins of Maize streak virus: implications for the transport of viral DNA

2001 ◽  
Vol 82 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Huanting Liu ◽  
Margaret I. Boulton ◽  
Karl J. Oparka ◽  
Jeffrey W. Davies
Keyword(s):  
Cell Movement ◽  
Systemic Infection ◽  
Maize Streak Virus ◽  
Streak Virus ◽  
Cell Periphery ◽  
Coat Proteins ◽  
Viral Dna ◽  
Dna Complex

We have shown previously that the movement protein (MP) and coat protein (CP) of Maize streak virus (MSV) are both required for systemic infection. Towards understanding the roles of these two proteins in virus movement, each was expressed in E. coli and interactions of the MP with viral DNA or CP were investigated using south-western, gel overlay and immunoprecipitation assays. Unlike the CP, the MP did not bind to viral DNA but it interacted with the CP in vitro and an MP–CP complex was detected in extracts from MSV-infected maize, indicating the potential for an interaction in vivo. Microinjection showed that the MP could prevent the nuclear transport of an MSV CP–DNA complex in maize and tobacco cells. These results are consistent with a model in which the MP diverts a CP–DNA complex from the nucleus (where viral DNA replication takes place) to the cell periphery, and in co-operation with the CP, mediates the cell-to-cell movement of the viral DNA. In this respect, the MSV MP and CP have functional analogy with the BC1 and BV1 proteins, respectively, of the Begomovirus genus of the Geminiviridae.

Maize streak virus research in Africa: an end or a crossroad

2021 ◽  
Author(s):  
Mary Emeraghi ◽  
Enoch G. Achigan-Dako ◽  
Chibuzo N. C. Nwaoguala ◽  
Happiness Oselebe
Keyword(s):  
Maize Streak Virus ◽  
Streak Virus ◽  
Virus Research
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