Retroviruses murine leukemia viruses

Miller, A. and Chen, F. (1996) Retrovirus packaging cells based on lOAl murine leukemia virus for production of vectors that use multiple receptors for cell entry. J VlrollO, 5564-5571. 

After obtaining pure total RNA from eukaryotic cells, the RNA needs to be rewritten into cDNA to serve as a template in PCR, as RNA cannot be amplified by PCR. The task of rewriting is accomplished with reverse transcriptase (RT), a viral enzyme used by retroviruses (whose name stems from harboring this enzyme and the ability to rewrite RNA into cDNA). The group of retroviruses has such members as the AIDS virus, Avian myeloblastosis virus, Murine leukemia virus (Frohmann, 1988 Kawasaki, 1988), and Adenovirus. Commonly employed reverse transcriptases stem from either the avian virus (AMV-RT) or the murine leukemia virus (MMLV, used in the Clontech RT-kit). 

Viruses. Rabbits have been induced to produce anti-RNP antibodies by immunization with the p30 gag protein, a protein of several mammalian C-type viruses (Ql). Blomberg et al. found an increased frequency of antibodies that were cross-reactive with baboon endogenous retrovirus and murine leukemia virus among 72 SLE patients compared with 88 controls (B17). Plotz found that autoantibodies in patients with lupus are antiidiotype antibodies to antiviral antibodies (P4). 

Fig. 9. Structures of soluble fragments of retrovirus TM proteins. Murine leukemia virus (MLV Fass et al, 1996) and filovirus (Weissenhom et al, 1998 Malashkevich et at, 1999) TM subunits are represented on the left by the HTLV TM structure (Kobe et at, 1999), with which they share remarkable similarity. Human and simian lentivirus TM subunits (Weissenhom etat, 1997 Chan etat, 1997 Caffrey etat, 1998) are represented by the structure of SIV TM on the right. Both structures are hairpins containing central three-stranded coiled coils surrounded by buttressing regions that pack into the grooves on the outsides of the coiled coils. The amino acid side chains in the conserved cysteine-rich motif of HTLV TM are shown as space-filling atoms and labeled according to their positions in the motif.

There are severable methodologies for expressing siRNAs. One method for stable and controlled expression of siRNAs from the context of the cell is via the use of len-tiviral vectors. Lentiviruses, unlike retroviruses such as Moloney murine leukemia virus (MoMLV), tend to preferentially integrate downstream of active promoters within the active transcriptional unit, potentially limiting their overall oncogenicity... 

Other enveloped retroviruses such as murine leukemia virus and Rous sarcoma virus also have been shown to require ESCRT complexes for their budding, although each virus appears to have evolved a somewhat different mechanism to recruit ESCRT complexes to the site of virus budding. 

I, virus validation must be conducted. Typical viruses studied are the murine leukemia virus as a model virus for retrovirus-like particles produced by murine cell expression systems (if applicable to the process) and parvovirus [50]. Before phase... 

Retroviral clearance in chromatography of antibody produced by hydrodomas Moloney murine leukemia virus (model retrovirus) used in scaled-down chromatography column [85] (Celltech)... 

The retroviral vectors in clinical use have mainly been derived from murine leukemia virus (MLV) [14]. MLV causes leukemia in mice and replication-competent retrovirus (RCR) in a contaminated vector preparation was shown to cause leukemia in severely immunosuppressed monkeys. RCR absence therefore has to be verified before human use of retroviraUy modified cells MLV vector use in vivo has been very rare. The genome of the retroviral vectors consists of two copies of single-stranded RNA, which contains one or more coding regions flanked by the viral control elements, the so-called long terminal repeat (LTR)... 

While there may be other drawbacks associated with their use, viruses represent the most effective method for introducing exogenous DNA into eukaryotic cells. As early as the 1960s, evidence existed that viruses could be used to genetically modify cells (Friedmann, 1992). By the mid-1980s, evidence existed that nearly 100% efficiency could be obtained with available viral systems. Over the last few decades, a variety of different viruses have become common tools cited in gene therapy literature. Both retroviruses (such as Maloney murine leukemia virus, lentivirus and semliki forest virus) and DNA viruses (which include adenovirus and adeno-associated virus [AAV]) have been applied in both in vitro and in vivo gene-therapy studies. 

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