Porcine endogenous retroviruses (PERVs) are members of family Retroviridae, genus Gamma retrovirus, and transmitted by both horizontally and vertically like other endogenous retroviruses (ERVs). PERV was initially described in the 1970s having inserted its gene in the host genome of different pig breeds, and three classes, PERV-A, PERV-B, and PERV-C are known. The therapeutic use of living cells, tissues, and organs from animals called xenotransplantation might relieve the limited supply of allografts in the treatment of organ dysfunction. Because of ethical considerations, compatible organ sizes, and physiology, the pig has been regarded as an alternative source for xenotransplantation. Sensitive duplex reverse transcription-polymerase chain reaction protocols for simultaneously detecting PERV gag mRNA and porcine glyceraldehydes 3-phosphate dehydrogenase mRNA in one tube was established. To compare the age-related PERV expression patterns of the lung, liver, spleen, kidney, heart, and pancreas in commercial pigs, 20 pigs from four age groups (5 heads each in 10 days-, 40 days-, 70 days-, and 110 days-old, respectively) were used in this study. The expression patterns of PERV were statistically different among age groups in lung, liver, and kidney (ANOVA, p<0.05). These data may support in the selection of appropriate donor pigs expressing low levels of PERV mRNA.
Animals ; Endogenous Retroviruses/*metabolism ; Gene Expression Regulation, Viral/*physiology ; RNA, Messenger/genetics/metabolism ; RNA, Viral/genetics/metabolism ; Reverse Transcriptase Polymerase Chain Reaction/methods/*veterinary ; Sensitivity and Specificity ; Swine/*virology

OBJECTIVETo investigate the expression of a novel retroviral (NP9) gene transcripts and the possible role of its protein in systemic lupus erythematosus (SLE) patients.

METHODSThe retroviral NP9 gene in SLE patients was isolated and cloned using RT-PCR and TA cloning techniques, and it was analyzed by sequencing. The expression of the NP9 genes in 40 patients with SLE and 48 normal controls using RT-PCR was detected. NCBI BLAST and DNASIS 3.1 software were used to analyze the features of protein of NP9 gene.

RESULTSThe positive ratio (77.5%) of the mRNA expression of the retroviral NP9 gene in SLE patients is significantly higher than that (8.3%) in normal subjects (P<0.01). The recombinant NP9 protein comprises 74 AA with pI 9.59. Amino acid sequence analysis indicates that the retroviral NP9 protein shares higher homologies with several human proteins with important biological functions.

CONCLUSIONSLE patients possess specific novel retroviral NP9 transcripts. The expression of the retroviral NP9 gene may involve in the genesis or development of SLE.

Amino Acid Sequence ; Computational Biology ; Endogenous Retroviruses ; genetics ; metabolism ; Humans ; Lupus Erythematosus, Systemic ; genetics ; physiopathology ; virology ; Molecular Sequence Data ; Retroviridae Proteins ; genetics ; metabolism ; physiology ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo assess the infectivity of porcine endogenous retrovirus (PERV) via in vitro infection of human embryonic kidney cell line HEK-293.

METHODSPERV particles were detected by immunoelectron microscopy. PERV DNA and mRNA were studied in HEK-293 24 hours after the infection using polymerase chain reaction and reverse transcriptase-PCR respectively. The PERV types were also analyzed. PERV-gag protein was observed by confocal microscopy.

RESULTSRetroviral particles were round under electron microscope. PERV-gag pol gene and gag protein were detected and expressed in the infected HEK-293 cells. The types of PERV were PERV-A and PERV-B. PERV-gag protein was also identified in the cytoplasm of infected cells by confocal microscopy.

CONCLUSIONSPERV is able to infect HEK-293 cell line in vitro; types of PERV-gag protein is also expressed as a result. Further studies are thus necessary in order to evaluate the possibility of xenozoonoses in pig-to-human xenotransplantation.

Animals ; Cell Line ; DNA, Viral ; analysis ; Embryo, Mammalian ; Endogenous Retroviruses ; isolation & purification ; pathogenicity ; Gene Amplification ; Gene Products, gag ; biosynthesis ; genetics ; Genes, gag ; Humans ; Kidney ; metabolism ; virology ; RNA, Messenger ; biosynthesis ; genetics ; Swine

OBJECTIVETo study the effect of NP9 on the growth of transplanted nasopharyngeal carcinoma (NPC) in nude mice and explore the mechanisms involved.

METHODSRecombinant pRc/CMV2-NP9 plasmid was constructed and transfected into the NPC cell lines by lipofectamine 2000. Cell clones stably expressing NP9 were obtained by detecting the mRNA expression of NP9 in G418-resistant clones with RT-PCR. The tumorigenicity and size of transplanted tumors were assessed after inoculation of NPC cells and their transgene clones into Balb/C mice. The expression of PCNA and cyclin D1 in transplanted tumors was detected by immunohistochemistry.

RESULTSThe expression of NP9 was detected in some of NP9 gene-transfected G418-resistant clones of CNE1 and SUNE1. In vivo experiments showed that the tumorigenicity of CNE19 clone was decreased significantly compared to that of CNE1 and its vector control, and the transplanted tumors grew more slowly from SUNE1/NP9 than from SUNE1 and SUNE1/vector. Compared with the vector control, the expression of cyclin D1 and PCNA in CNE1/NP9 transplants was decreased.

CONCLUSIONNP9 inhibits tumorigenicity and growth of NPC transplanted tumor by down-regulating the expression of cyclin D1 and PCNA.

Animals ; Cyclin D1 ; biosynthesis ; genetics ; Endogenous Retroviruses ; genetics ; Female ; Gene Products, env ; biosynthesis ; genetics ; Genes, Tumor Suppressor ; Humans ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Nasopharyngeal Neoplasms ; genetics ; metabolism ; pathology ; Neoplasm Transplantation ; Proliferating Cell Nuclear Antigen ; biosynthesis ; genetics ; Tumor Cells, Cultured