Human leukemia is closely associated with various genetic alterations such as chromosomal translocations and gene mutations. The use of retroviral transduction/bone marrow transplantation mouse model harboring these genetic abnormalities has been critical in understanding the molecular pathogenesis of leukemia and exploring new therapeutic target. Additional genetic events are verified to cooperate with fusion genes resulting from chromosomal translocations in acute myeloid leukemia (AML) to develop a leukemic phenotype in mice, such as C-KIT N822K with AML1-ETO, FLT3-ITD with PML-RARα, Meis1 with NUP98-HOX, and Cdx4 with MLL-AF9. Mouse model shows that BCR/ABL fusion gene induces chronic myeloid leukemia (CML), and suggests that GATA-2 L359V and high expression of Hes1 are key molecules in acute myeloid transformation of CML. Furthermore, combination therapy with Imatinib and arsenic sulfide for CML mice exerts more profound therapeutic effects than either drug as a single agent. This review focuses the recent progress and application of retroviral-mediated mouse models of myeloid leukemia, and discusses some factors influencing the mouse model establishment, including retroviral construction, retrovirus titer and hematopoietic microenvironment.
Animals ; Disease Models, Animal ; Leukemia, Myeloid ; genetics ; Mice ; Retroviridae ; genetics

Foamy virus can establish lifelong persistent infection in mammal hosts without inducing diseases. Such special characteristic stimulates the interests of researchers. As reported, the accessory protein Bet of foamy virus could regulate the gene expression and infection cycle of foamy virus and take part in the generation of chronic viral infection. And also, Bet might prevent the host cellular defense factor APO-BEC3 from interfering the replication of virus and play a role in maintaining viral persistent infection. In order to elucidate the roles of Bet in the foamy virus replication and infection, this review summarized the research progress of Bet protein reported in recent years.
Animals ; Gene Expression Regulation, Viral ; Humans ; Retroviridae Infections ; immunology ; virology ; Retroviridae Proteins ; genetics ; metabolism ; Spumavirus ; genetics ; metabolism

This study was purposed to construct the recombinant retroviral vector containing human homeobox gene hoxA10 and to establish the packaging cell lines which stably produce viruses. The whole coding region of hoxA10 gene was amplified by PCR and inserted into the retroviral vector MSCVneo. The recombinant vector was identified by DNA sequencing. The recombinant and control retroviral vectors were transfected into the packaging cell line PT67 by liposome Lipofectamine(TM) 2000. These cell lines stably producing retrovirus were isolated following G418 selection. The viral suspension was harvested and the viral titer was determined by NIH3T3 cells. The results showed that the recombinant retroviral vector was proved to encode hoxA10 genes by sequencing. The cell lines efficiently producing virus were screened by G418 and designated as PT67/MSCVneo and PT67/MSCVneo-hoxA10. The titers of them were 5 x 10(5) CFU/ml and 4 x 10(4) CFU/ml respectively. It is concluded that the recombinant retroviral vector containing homeobox gene hoxA10 and the stably packaging cell lines which efficiently and correctly produce viruses are successfully constructed, which provides a basis for further exploration of the hoxA10 gene function in the regulation of hematopoiesis.
Cell Line ; Genes, Homeobox ; Genetic Vectors ; Homeodomain Proteins ; genetics ; Humans ; Retroviridae ; genetics ; Transfection

OBJECTIVETo clone hsa-miR-148a and construct its retroviral expression vector.

METHODSThe pre-miR-148a amplified by PCR was inserted to pMSCV to construct the recombinant retroviral expression plasmid pMSCV-miR-148a, which was confirmed by restriction endonuclease analysis and DNA sequencing. The retroviral expression vector pMSCV-miR-148a and PIK packaging plasmid were cotransfected into 293FT packaging cells by calcium phosphate-mediated transfection to produce the retrovirus, and the retrovirus titer was measured by infection of NIH3T3 cells.

RESULTSRestriction enzyme digestion and DNA sequencing demonstrated that the retroviral vector pMSCV-miR-148a was constructed successfully, and the virus titer was 5x10(8) CFU/ml after infection of NIH3T3 cells.

CONCLUSIONThe successful construction of the retroviral expression vector MSCV-miR-148a allows the production of high-titer retrovirus to facilitate further study of the molecular functions of miR-148a.

Base Pairing ; Dimerization ; Genome, Viral ; RNA, Viral ; chemistry ; genetics ; Retroviridae ; chemistry ; genetics

To explore feasibility of real-time quantitative PCR in assessing efficiency of gene transfection, clonal PCR was employed to analyze efficiency of retroviral-mediated neo gene transfection in primary myoblast, simultaneous real-time PCR were performed for estimation of transfection efficiency; for measuring integrated gene copy number per cell, linear amplification mediated-PCR (LAM-PCR) and retroviral 5'LTR integration analysis also were used. The results showed that: (1) the data from clonal PCR are similar as that from real-time PCR in low efficiency of transfection (< 36%); but in high efficiency of transfection, it is significantly differentiation between clonal PCR and real-time PCR. (2) One copy of transduced gene per cell was observed in retroviral-mediated gene transfection in primary myoblast. It is concluded that real-time PCR can be used to estimate gene transfer vector in vivo, but it is not available for assessing gene transfection in vitro, because high efficiency of transfection could be obtained in most of gene transfection in vitro.
Animals ; Genetic Vectors ; genetics ; Polymerase Chain Reaction ; methods ; Retroviridae ; genetics ; Sequence Analysis, DNA ; Transfection

OBJECTIVETo explore use of retroviral vector in gene therapy of hepatitis B.

METHODSThe recombinant vector Plxsn-HBs was constructed by inserting HBV S gene into pLXSN. The pseudovirus, which was produced from PA317 after transferring with pLXSN-HBs by electroporation, were frozen at different temperature. The activities of the pseudovirus to infect eukaryotic cells and express antigen were determined by comparing the numbers of G418-resistant clones and assaying HBsAg in the supernatant of the cells with ELISA after infection HepG2, NIH3T3 and 293 cells.

RESULTSIt was hard to find changes in HBsAg amount at different intervals and different temperatures. G418 resistant clones, however, were variable. When frozen at -20 degrees C, the numbers of clones were half less than that of the beginning after 6 months, few clones were formed after 12 months, and no clone was found after 24 months. When frozen at -40 degrees C, the numbers of clones were 121, 332 and 89 42, 137 and 43 for HepG2, NIH3T3 and 293 cell lines at 12 and 24 months, respectively. When frozen at -70 degrees C, the numbers of clones were 159 463 and 112 for HepG2, NIH3T3 and 293 cell lines at 24 months, respectively. There was no statistical difference compared to that of zero months.

CONCLUSIONSThe activity of the peseudovirus to infect eukaryotic cells and expressed antigen was not changed after 2 years frozen at -70 degrees C.

Transgenic chicken and oviduct bioreactor are growing to be one of the hotspot of scientific study in the field of biology. The most successful method of producing transgenic chicken is pseudotyped retrovirus vector system, but no one has reported the production of transgenic chicken by retrovirus system recently in our country. In order to accelerate our study in this field, we introduced the relevant technical methods such as packaging retrovirus and vesicular stomatitis virus G glycoprotein (VSV-G) pseudotyped retrovirus, optimizing the conditions of packaging retrovirus, concentrating VSV-G pseudotyped retrovirus, helper virus assays, and microinjection of retrovirus. Furthermore, we successfully conducted in vivo study for detecting the marker gene EGFP of chicken embryo as well as in vitro study for detecting that gene of chicken embryo myoblast (CFM), thus we have provided an applied technical platform for studies of transgenic chicken in the future.
Animals ; Animals, Genetically Modified ; Chick Embryo ; Chickens ; genetics ; DNA Primers ; Genetic Vectors ; genetics ; Retroviridae ; genetics ; Vesicular stomatitis Indiana virus ; genetics

This study aimed to construct the dual expression vectors of wide type or N187D mutant P2X7 receptor and intracellular domain of Notch1 (ICN1) linked by 2A peptide to coexpress them in leukemia cells so as to lay a foundation for further investigating the role of P2X7 in development of leukemia. Overlap PCR was used to construct the dual expression vectors encoding wide type or N187D mutant type P2X7 receptor and ICN1 linked by the self-cleaving 2A sequence. The results showed that stable expressing cell lines were obtained by retroviral infection followed by cell sorting after DNA sequence analysis. RT-PCR, Western blot, intracellular free calcium concentration analysis were used to verify the functionally successful construction of K562 cell line expressing P2X7 receptor alone or with ICN1. DNA sequence analysis revealed that all construction were right. The infection efficiency of packaged constructed virus ranged from 40% to 70% for K562 cells. Stable infected cell line was obtained by cell sorting. RT-PCR analysis revealed that P2X7 receptor and/or ICN1 could be detected at high level in their stable infected cell lines, respectively. Western blot analysis also showed that P2X7 receptor was highly expressed in cell line infected by virus with P2X7 receptor. Sustained increase in intracellular free calcium concentration ([Ca(2+)]i) could be observed in K562 cells overexpressing either type of P2X7 receptor upon stimulation with BzATP. It is concluded that the wide type or N187D mutant P2X7 receptor and ICN1 are simultaneously and functionally over-express in leukemia cells, which lay a foundation for further studying the role of P2X7 receptor in the development of leukemia.
Gene Expression ; Genetic Vectors ; Humans ; K562 Cells ; RNA, Messenger ; genetics ; Receptor, Notch1 ; genetics ; Receptors, Purinergic P2X7 ; genetics ; Retroviridae ; genetics

Bel1, a transactivator of prototype foamy virus (PFV), plays pivotal roles in the replication of PFV. Previous studies have shown that Bel1 bears a nuclear localization signal (NLS), but its amino acid sequence remains unclear and the corresponding importins have not been identified. In this report, we inserted various fragments of Bel1 into an EGFP-GST fusion protein and investigated their subcellular localization by fluorescence microscopy. We found that the 215PRQKRPR221 fragment could direct nuclear localization, which accords with the consensus sequence K(K/R)X(K/R) of monopartite NLS. Point mutation experiments revealed that K218, R219, and R221 are essential for the nuclear localization of Bel1. The results of the GST-pulldown showed that the Bel1 fragment with residues 215-223, which bears the NLS, interacts with KPNA1, KPNA6, and KPNA7. This result suggests that KPNA1, KPNA6, and KPNA7 maybe involved in Bel1 nuclear translocation.
Cell Line ; Cell Nucleus ; genetics ; metabolism ; virology ; Humans ; Nuclear Localization Signals ; genetics ; metabolism ; Protein Binding ; Protein Transport ; Retroviridae Infections ; genetics ; metabolism ; virology ; Retroviridae Proteins ; chemistry ; genetics ; metabolism ; Spumavirus ; chemistry ; genetics ; physiology ; Trans-Activators ; chemistry ; genetics ; metabolism ; alpha Karyopherins ; genetics ; metabolism