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Generation of recombinant vaccinia viruses via green fluorescent protein selection.

ABSTRACT: We developed a rapid method to generate recombinant vaccinia viruses (rVVs) based upon a bicistronic cassette encoding the gene for green fluorescent protein (GFP) and a foreign gene of interest separated by an internal ribosome entry site (IRES). As proof-of-concept, we inserted a mutant env gene of human immunodeficiency virus (HIV) into the cassette, which was cloned into the vaccinia virus (VV) insertion vector pSC59 under the control of the early-late VV synthetic promoter and flanked by disrupted tk gene sequences. To generate rVVs, 293T cells were inoculated with wild-type (wt) VV, followed by transfection of the modified pSC59 vector containing the bicistronic cassette, which allows expression of GFP and the protein of interest. Next, GFP-positive cells were isolated by flow cytometry or by picking under a fluorescent microscope. Thymidine kinase-deficient (Tk(-)) 143B cells were then exposed to lysates of GFP-positive 293T cells and cultured in the presence of bromodeoxyuridine. This selection allows only Tk(-) rVV to remain viable. We demonstrated the success of this GFP selection strategy by expressing high levels of mutant HIV Env. Our approach shortens the time needed to generate rVVs and represents a practical approach to generate recombinant proteins.

SUBMITTER: Popov S

PROVIDER: S-EPMC2925039 | biostudies-literature | 2009 Mar

REPOSITORIES: biostudies-literature

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Generation of recombinant vaccinia viruses via green fluorescent protein selection.

Popov Sergei S Mirshahidi Saied S Essono Sosthène S Song Ruijiang R Wang Xiaowei X Ruprecht Ruth M RM

DNA and cell biology 20090301 3

We developed a rapid method to generate recombinant vaccinia viruses (rVVs) based upon a bicistronic cassette encoding the gene for green fluorescent protein (GFP) and a foreign gene of interest separated by an internal ribosome entry site (IRES). As proof-of-concept, we inserted a mutant env gene of human immunodeficiency virus (HIV) into the cassette, which was cloned into the vaccinia virus (VV) insertion vector pSC59 under the control of the early-late VV synthetic promoter and flanked by di ...[more]

PMID: 19182996

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Project description:UnlabelledOropouche virus (OROV) is a midge-borne human pathogen with a geographic distribution in South America. OROV was first isolated in 1955, and since then, it has been known to cause recurring outbreaks of a dengue-like illness in the Amazonian regions of Brazil. OROV, however, remains one of the most poorly understood emerging viral zoonoses. Here we describe the successful recovery of infectious OROV entirely from cDNA copies of its genome and generation of OROV mutant viruses lacking either the NSm or the NSs coding region. Characterization of the recombinant viruses carried out in vitro demonstrated that the NSs protein of OROV is an interferon (IFN) antagonist as in other NSs-encoding bunyaviruses. Additionally, we demonstrate the importance of the nine C-terminal amino acids of OROV NSs in IFN antagonistic activity. OROV was also found to be sensitive to IFN-α when cells were pretreated; however, the virus was still capable of replicating at doses as high as 10,000 U/ml of IFN-α, in contrast to the family prototype BUNV. We found that OROV lacking the NSm protein displayed characteristics similar to those of the wild-type virus, suggesting that the NSm protein is dispensable for virus replication in the mammalian and mosquito cell lines that were tested.ImportanceOropouche virus (OROV) is a public health threat in Central and South America, where it causes periodic outbreaks of dengue-like illness. In Brazil, OROV is the second most frequent cause of arboviral febrile illness after dengue virus, and with the current rates of urban expansion, more cases of this emerging viral zoonosis could occur. To better understand the molecular biology of OROV, we have successfully rescued the virus along with mutants. We have established that the C terminus of the NSs protein is important in interferon antagonism and that the NSm protein is dispensable for virus replication in cell culture. The tools described in this paper are important in terms of understanding this important yet neglected human pathogen.

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Generation of recombinant vaccinia viruses via green fluorescent protein selection.

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Generation of recombinant vaccinia viruses via green fluorescent protein selection.

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