Transposable elements (TEs), once considered genomic "junk", are now recognized as critical regulators of genome function and human disease. These mobile genetic elements-including retrotransposons (long interspersed nuclear elements [LINE-1], Alu, short interspersed nuclear element-variable numbers of tandem repeats-Alu [SVA], and human endogenous retrovirus [HERV]) and DNA transposons-are tightly regulated by multilayered mechanisms that operate from transcription through to genomic integration. Although typically silenced in somatic cells, TEs are transiently activated during key developmental stages-such as zygotic genome activation and cell fate determination-where they influence chromatin architecture, transcriptional networks, RNA processing, and innate immune responses. Dysregulation of TEs, however, can lead to genomic instability, chronic inflammation, and various pathologies, including cancer, neurodegeneration, and aging. Paradoxically, their reactivation also presents new opportunities for clinical applications, particularly as diagnostic biomarkers and therapeutic targets. Understanding the dual role of TEs-and balancing their contributions to normal development and disease-is essential for advancing novel therapies and precision medicine.
Humans ; DNA Transposable Elements/physiology* ; Animals ; Long Interspersed Nucleotide Elements/genetics* ; Neoplasms/genetics* ; Genomic Instability/genetics* ; Endogenous Retroviruses/genetics*

OBJECTIVETo investigate the molecular?mechanisms by which triptolide induces apoptosis of human acute T lymphocytic leukemia Jurkat cells.

METHODSMTT assay was employed to detect the proliferation inhibition of Jurkat cells by triptolide, and the IC50 was calculated by OriginPro8. Flow cytometry was used to analyze apoptosis of Jurkat cells. Np9 mRNA levels were detected by RT-PCR and analyzed quantitatively by Kodak 1D 3.6 software. Correlation between the inhibition of Np9 transcription and the cell apoptosis was analyzed by SPSS 19.0.Western blotting was employed to determine Np9 downstream signaling molecules c-myc, β-catenin, ERK, AKT and Notch1 protein level in Jurkat cells after exposure to different concentrations of triptolide for 48 h.

RESULTSTriptolide treatment resulted in dose-dependent inhibition of Jurkat cells proliferation and its IC50 was 12.7 nmol/L. Triptolide induced apoptosis of Jurkat cells in dose- dependent manner. Furthermore, triptolide inhibited Np9 mRNA transcription level in Jurakt cells in a dose-dependent manner. There was a correlation between the triptolide-mediated the apoptosis and the inhibition of Np9 transcription of Jurkat cells (R(2)=0.907). Western blotting results displayed that triptolide inhibited transcription levels of Np9 mRNA with a concomitant decrease of its downstream signaling molecules c-myc, β-catenin, ERK, AKT and Notch1 at protein levels.

CONCLUSIONInhibition of HERV-K Np9 mRNA and its downstream signaling molecules c-myc, β-catenin, ERK, Akt and Notch1 protein might be one of important molecular?mechanisms by which triptolide induces apoptosis of human acute T lymphocytic leukemia Jurkat cells.

Apoptosis ; drug effects ; Diterpenes ; pharmacology ; Endogenous Retroviruses ; genetics ; Epoxy Compounds ; pharmacology ; Flow Cytometry ; Gene Products, env ; genetics ; Humans ; Jurkat Cells ; drug effects ; Phenanthrenes ; pharmacology ; Precursor T-Cell Lymphoblastic Leukemia-Lymphoma ; pathology ; Transcription, Genetic

Ovine pulmonary adenomatosis (OPA) is a naturally occurring contagious lung tumor of sheep which was caused by an exogenous retrovirus of sheep, jaagsiekte retrovirus (JSRV). Although no specific circulating antibodies against the virus coud be detected in infected sheep, exogenous JSRV proviral DNA sequences (exJSRV) and JSRV RNA transcripts could be detected in lung tumors, lymphoreticular system and peripheral blood mononuclear cells (PBMC) from sheep affected by OPA. The sheep genome carried 15 to 20 copies of endogenous retrovirus loci (enJSRV) that were similar to JSRV in structural genes but the divergene in U3. Therefore, primers specific for the U3 sequences of exJSRV were designed for the specific PCR and nested PCR (n-PCR). Sensitivity between specific PCR assay and n-PCR assay was compared by using serial dilutions of positive plasmid pJSRV-LTR in a background of 700ng sheep genome DNA. Sensitivity of n-PCR was ten-fold higher than specific PCR. The n-PCR was only available in blood test for detection of JSRV infected sheep and might be useful in epidemiological studies and disease control of OPA.
Animals ; Base Sequence ; Clinical Laboratory Techniques ; DNA, Viral ; analysis ; Endogenous Retroviruses ; genetics ; Jaagsiekte sheep retrovirus ; genetics ; Lung Neoplasms ; virology ; Molecular Sequence Data ; Polymerase Chain Reaction ; Pulmonary Adenomatosis, Ovine ; virology ; Reverse Transcriptase Polymerase Chain Reaction ; Sensitivity and Specificity ; Sequence Analysis, DNA ; Sheep ; Sheep Diseases ; virology ; Virus Cultivation

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 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

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