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Zhang M, Liang JQ, Zheng S. Expressional activation and functional roles of human endogenous retroviruses in cancers. Rev Med Virol 2019; 29:e2025. [PMID: 30614117 PMCID: PMC6590502 DOI: 10.1002/rmv.2025] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 10/26/2018] [Accepted: 11/05/2018] [Indexed: 12/26/2022]
Abstract
Human endogenous retroviruses (HERVs) are widely believed to be remnants of ancestral germ line infections by exogenous retroviruses. Although HERVs are deemed as “nonfunctional DNAs” due to loss of most of their viral protein coding capacity during evolution as part of the human genome, cumulative evidences are showing the expressional activation and potential roles of HERVs in diseases especially cancers. Work by other researchers and us has observed the dysregulation of HERVs in cancers, identified new HERV‐related genes, and revealed their potential importance in cancer development. Here, we summarized the current knowledge on the mechanisms of the expressional activation and functional roles of HERVs, with a focus on the H family HERV (HERV‐H), in carcinogenesis. HERV expression is regulated by external chemical or physical substances and exogenous virus infection, as well as host factors such as epigenetic DNA methylation, transcription factors, cytokines, and small RNAs. Diverse roles of HERVs have been proposed by acting in the forms of noncoding RNAs, proteins, and transcriptional regulators during carcinogenesis. However, much remains to be learnt about the contributions of HERVs to human cancers. More investigation is warranted to elucidate the functions of these “fossil remnants” yet important viral DNAs in the human genome.
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Affiliation(s)
- Mengwen Zhang
- The Department of Plastic and Reconstructive Surgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.,Cancer Institute, Second Affiliated Hospital, and Ministry of Education Key Laboratory of Cancer Prevention and Intervention, Zhejiang University School of Medicine, Hangzhou, China
| | - Jessie Qiaoyi Liang
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Shu Zheng
- Cancer Institute, Second Affiliated Hospital, and Ministry of Education Key Laboratory of Cancer Prevention and Intervention, Zhejiang University School of Medicine, Hangzhou, China.,The Department of surgical oncology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
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2
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Krönung SK, Beyer U, Chiaramonte ML, Dolfini D, Mantovani R, Dobbelstein M. LTR12 promoter activation in a broad range of human tumor cells by HDAC inhibition. Oncotarget 2018; 7:33484-97. [PMID: 27172897 PMCID: PMC5085097 DOI: 10.18632/oncotarget.9255] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 04/19/2016] [Indexed: 01/31/2023] Open
Abstract
A considerable proportion of the human genome consists of transposable elements, including the long terminal repeats (LTRs) of endogenous retroviruses. During evolution, such LTRs were occasionally inserted upstream of protein-coding genes, contributing to their regulation. We previously identified the LTR12 from endogenous retrovirus 9 (ERV9) as a regulator of proapoptotic genes such as TP63 or TNFRSF10B. The promoter activity of LTR12 is largely confined to the testes, silenced in testicular carcinoma, but reactivated in testicular cancer cells by broad-range histone deacetylase (HDAC) inhibitors. Here we show that inhibition of HDAC1-3 is sufficient for LTR12 activation. Importantly, HDAC inhibitors induce LTR12 activity not only in testicular cancer cells, but also in cells derived from many additional tumor species. Finally, we characterize the transcription factor NF-Y as a mediator of LTR12 promoter activity and HDAC inhibitor-induced apoptosis, in the context of widespread genomic binding of NF-Y to specific LTR12 sequences. Thus, HDAC inhibitor-driven LTR12 activation represents a generally applicable means to induce proapoptotic genes in human cancer cells.
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Affiliation(s)
- Sonja K Krönung
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center, University of Göttingen, Göttingen, Germany
| | - Ulrike Beyer
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center, University of Göttingen, Göttingen, Germany.,Institute of Human Genetics, Hannover Medical School, Hannover, Germany
| | | | - Diletta Dolfini
- Dipartimento di Bioscienze, UniversitàdegliStudi di Milano, Via Celoria, Milan, Italy
| | - Roberto Mantovani
- Dipartimento di Bioscienze, UniversitàdegliStudi di Milano, Via Celoria, Milan, Italy
| | - Matthias Dobbelstein
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center, University of Göttingen, Göttingen, Germany
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3
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Zhao J, Rycaj K, Geng S, Li M, Plummer JB, Yin B, Liu H, Xu X, Zhang Y, Yan Y, Glynn SA, Dorsey TH, Ambs S, Johanning GL, Gu L, Wang-Johanning F. Expression of Human Endogenous Retrovirus Type K Envelope Protein is a Novel Candidate Prognostic Marker for Human Breast Cancer. Genes Cancer 2012; 2:914-22. [PMID: 22593804 DOI: 10.1177/1947601911431841] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2011] [Accepted: 11/04/2011] [Indexed: 01/14/2023] Open
Abstract
We previously observed that the HERV type K (HERV-K) envelope (env) protein was expressed in the majority of human breast tumors from a U.S. cohort of women from Texas. We also made the preliminary observation that the expression of HERV-K env transcripts was associated with markers of disease progression. In this follow-up study, env protein expression was evaluated immunohistochemically in an additional 195 paraffin-embedded breast tumors from a second U.S. patient cohort (Baltimore, Maryland) and in 110 tumors from Chinese patients. Moreover, we compared env transcript expression between fresh-frozen normal and cancerous breast tissues. We observed that while env mRNA and protein expression was undetectable in normal breast tissue and in a subset of uninvolved normal-appearing tissue adjacent to the tumor epithelium, it was overexpressed in most tumors. Furthermore, env expression was associated with breast cancer progression. In Baltimore cohort women, HERV-K tumor positivity was significantly associated with disease stage and lymph node metastasis. In Chinese women, HERV-K env positivity was significantly associated with tumor size, TNM stage, and lymph node metastases, which is consistent with the observations in the U.S. cohort. We also found that Chinese breast cancer patients with a high expression of HERV-K had a decreased overall survival compared with patients who had either a moderate or low HERV-K expression in their tumors (P = 0.049, χ(2) log rank test). In conclusion, the HERV-K env gene is expressed in the majority of breast cancers from U.S. or Chinese women but not in normal breast tissue. High expression of HERV-K env protein in breast cancer patients is associated with markers of disease progression and poor disease outcome, indicating that HERV-K env protein is a novel candidate prognostic marker for breast cancer.
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Affiliation(s)
- Jing Zhao
- Cancer Institute and Hospital of Tianjin Medical University, Tianjin, China
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4
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Kim HS. Genomic impact, chromosomal distribution and transcriptional regulation of HERV elements. Mol Cells 2012; 33:539-44. [PMID: 22562360 PMCID: PMC3887755 DOI: 10.1007/s10059-012-0037-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 04/10/2012] [Accepted: 04/12/2012] [Indexed: 10/28/2022] Open
Abstract
Human endogenous retroviruses (HERVs) mediate structural variation and genomic instability based on their multiple copy number, inherent ability to mobilize via reverse transcriptase, and high sequence similarity. Moreover, they undergo multiple amplification and retrotransposition events, resulting in the widespread distribution of complete or partial retroviral sequences throughout the primate genome. As such, HERV elements have played important biological roles in genome evolution, and their long terminal repeat (LTR) elements contain numerous regulatory sequences, including effective promoters, enhancers, polyadenylation signals, and transcription factorbinding sites. Lastly, HERV elements are capable of influencing the expression of neighboring genes, a process that also contributed to primate evolution.
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Affiliation(s)
- Heui-Soo Kim
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan 609-735, Korea.
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5
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Antony JM, Deslauriers AM, Bhat RK, Ellestad KK, Power C. Human endogenous retroviruses and multiple sclerosis: innocent bystanders or disease determinants? Biochim Biophys Acta Mol Basis Dis 2010; 1812:162-76. [PMID: 20696240 PMCID: PMC7172332 DOI: 10.1016/j.bbadis.2010.07.016] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 07/14/2010] [Accepted: 07/26/2010] [Indexed: 12/21/2022]
Abstract
Human endogenous retroviruses (HERVs) constitute 5–8% of human genomic DNA and are replication incompetent despite expression of individual HERV genes from different chromosomal loci depending on the specific tissue. Several HERV genes have been detected as transcripts and proteins in the central nervous system, frequently in the context of neuroinflammation. The HERV-W family has received substantial attention in large part because of associations with diverse syndromes including multiple sclerosis (MS) and several psychiatric disorders. A HERV-W-related retroelement, multiple sclerosis retrovirus (MSRV), has been reported in MS patients to be both a biomarker as well as an effector of aberrant immune responses. HERV-H and HERV-K have also been implicated in MS and other neurological diseases but await delineation of their contributions to disease. The HERV-W envelope-encoded glycosylated protein, syncytin-1, is encoded by chromosome 7q21 and exhibits increased glial expression within MS lesions. Overexpression of syncytin-1 in glia induces endoplasmic reticulum stress leading to neuroinflammation and the induction of free radicals, which damage proximate cells. Syncytin-1's receptor, ASCT1 is a neutral amino acid transporter expressed on glia and is suppressed in white matter of MS patients. Of interest, antioxidants ameliorate syncytin-1's neuropathogenic effects raising the possibility of using these agents as therapeutics for neuroinflammatory diseases. Given the multiple insertion sites of HERV genes as complete and incomplete open reading frames, together with their differing capacity to be expressed and the complexities of individual HERVs as both disease markers and bioactive effectors, HERV biology is a compelling area for understanding neuropathogenic mechanisms and developing new therapeutic strategies.
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6
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Human endogenous retrovirus (HERV-K) reverse transcriptase as a breast cancer prognostic marker. Neoplasia 2008; 10:521-33. [PMID: 18516289 DOI: 10.1593/neo.07986] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Revised: 03/27/2008] [Accepted: 03/29/2008] [Indexed: 11/18/2022] Open
Abstract
A reverse transcriptase (RT) cDNA, designated HERV-K-T47D-RT, was isolated from a hormonally treated human breast cancer cell line. The protein product putative sequence is 97% identical to the human endogenous HERV-K retroviral sequences. Recombinant T47D-RT protein was used to generate polyclonal antibodies. The expression of HERV-K-T47D-RT protein increased in T47D cells after treatment with estrogen and progesterone. The RT-associated DNA polymerase activity was substantially increased after over-expressing a chimeric YFP-HERV-K-T47D-RT protein in cells. This RT-associated polymerase activity was significantly reduced by mutating the active site sequence YIDD to SIAA. Moreover, the endogenous RT activity observed in T47D cells was decreased by HERV-K-T47D-RT-specific siRNA, confirming the dependence of the endogenous enzymatic activity. To assess HERV-K-T47D-RT expression in human breast tumors, 110 paraffin sections of breast carcinoma biopsies were stained and subjected to confocal analysis. Twenty-six percent (28/110) of the tumor tissues and 18% (15/85) of the adjacent normal tissue, from the same patients, expressed the RT. HERV-K-T47D-RT expression significantly correlates with poor prognosis for disease-free patients and their overall survival. These results imply that HERV-K-T47D-RT might be expressed in early malignancy and might serve as a novel prognostic marker for breast cancer. Furthermore, these results provide evidence for the possible involvement of endogenous retrovirus in human breast carcinoma.
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Sperber GO, Airola T, Jern P, Blomberg J. Automated recognition of retroviral sequences in genomic data--RetroTector. Nucleic Acids Res 2007; 35:4964-76. [PMID: 17636050 PMCID: PMC1976444 DOI: 10.1093/nar/gkm515] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Eukaryotic genomes contain many endogenous retroviral sequences (ERVs). ERVs are often severely mutated, therefore difficult to detect. A platform independent (Java) program package, RetroTector© (ReTe), was constructed. It has three basic modules: (i) detection of candidate long terminal repeats (LTRs), (ii) detection of chains of conserved retroviral motifs fulfilling distance constraints and (iii) attempted reconstruction of original retroviral protein sequences, combining alignment, codon statistics and properties of protein ends. Other features are prediction of additional open reading frames, automated database collection, graphical presentation and automatic classification. ReTe favors elements >1000-bp long due to its dependence on order of and distances between retroviral fragments. It detects single or low-copy-number elements. ReTe assigned a ‘retroviral’ score of 890–2827 to 10 exogenous retroviruses from seven genera, and accurately predicted their genes. In a simulated model, ReTe was robust against mutational decay. The human genome was analyzed in 1–2 days on a LINUX cluster. Retroviral sequences were detected in divergent vertebrate genomes. Most ReTe detected chains were coincident with Repeatmasker output and the HERVd database. ReTe did not report most of the evolutionary old HERV-L related and MalR sequences, and is not yet tailored for single LTR detection. Nevertheless, ReTe rationally detects and annotates many retroviral sequences.
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Affiliation(s)
- Göran O. Sperber
- Department of Neuroscience, Physiology and Section of Virology, Department of Medical Sciences, Uppsala University, Uppsala and Department of Biology and Chemical Engineering, Mälardalens Högskola, Eskilstuna, Sweden
| | - Tove Airola
- Department of Neuroscience, Physiology and Section of Virology, Department of Medical Sciences, Uppsala University, Uppsala and Department of Biology and Chemical Engineering, Mälardalens Högskola, Eskilstuna, Sweden
| | - Patric Jern
- Department of Neuroscience, Physiology and Section of Virology, Department of Medical Sciences, Uppsala University, Uppsala and Department of Biology and Chemical Engineering, Mälardalens Högskola, Eskilstuna, Sweden
| | - Jonas Blomberg
- Department of Neuroscience, Physiology and Section of Virology, Department of Medical Sciences, Uppsala University, Uppsala and Department of Biology and Chemical Engineering, Mälardalens Högskola, Eskilstuna, Sweden
- *To whom correspondence should be addressed.+46 18 611 55 93+46 18 55 10 12
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8
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Yi JM, Kim HS. Molecular Phylogenetic Analysis of the Human Endogenous Retrovirus E (HERV-E) Family in Human Tissues and Human Cancers. Genes Genet Syst 2007; 82:89-98. [PMID: 17396023 DOI: 10.1266/ggs.82.89] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The human genome is estimated to contain up to 50 copies of full-length and truncated members of HERV-E family. They are thought to be involved in human gene transcription. Here we examine the expression pattern and phylogenetic relationships of the HERV-E in diverse human tissues and cancer cells using RT-PCR amplification and bioinformatic tools. The env gene was expressed in many human tissues (brain, prostate, testis, kidney, placenta, spleen, thymus and uterus) but not in heart, liver, lung and skeletal muscle, importantly, HERV-E expression was detected in all cancer cell lines examined (RT4, PFSK-1, BT-474, HCT-116, TE-1, UO-31, Jurkat, HepG2, A549, MCF7, OVCAR-3, MIA-PaCa-2, PC3, LOX-IMVI, AZ521, 2F7, U-937 and C-33A), suggesting that HERV-E family are expressed corresponding to the transcriptional program of human tissues and human cancer cells. Phylogenetic analysis of HERV-E env family from human tissues, cancer cells and our previous data identify two groups (I and II) through evolutionary divergence. Taken together, HERV-E family expression in human tissues and human cancer cells exhibited close relationships of the env gene sequences across human chromosomes. These active HERV-E elements deserve further investigation as potential pathogenic factors in human diseases such as cancers.
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Affiliation(s)
- Joo-Mi Yi
- Division of Biological Sciences, College of Natural Sciences, Pusan National University, Korea
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9
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Yi JM, Kim HS. Molecular evolution of the HERV-E family in primates. Arch Virol 2006; 151:1107-16. [PMID: 16385394 DOI: 10.1007/s00705-005-0701-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Accepted: 11/25/2005] [Indexed: 10/25/2022]
Abstract
More than 50 copies of HERV-E family elements have been estimated to exist in the human genome. Here we examined the recent evolutionary history of the HERV-E family by a PCR approach using genomic DNA from hominoid primates and a human monochromosomal panel. From the HERV-E family, 25 and 68 env fragments, were identified and analyzed from hominoid primates and human chromosomes 1, 2, 3, 4, 6, 7, 8, 10, 11, 12, 13, 14, 15, 16, 17, 19, X, and Y, respectively. They showed 76.7-99.6% sequence similarity to that of HERV-E (accession no. M10976). Phylogenetic analysis of HERV-E env family distinctively divided into two groups (groups I and II) that each contained three subgroups. Divergence times of the two groups were estimated as 10.7 MYr for group I and 41.3 MYr for group II using an average evolutionary rate of 0.3% per MYr. These data are consistent with that of PCR analysis, which showed a band of the HERV-E family in the genomes of the hominoids, Old World monkeys, and New World monkeys. Therefore, the HERV-E family may have integrated into the primate genome after prosimians and New World monkeys diverged. Then they proliferated extensively in the genome of humans and great apes during primate evolution.
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Affiliation(s)
- J-M Yi
- Division of Biological Sciences, College of Natural Sciences, Pusan National University, Pusan, Korea
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10
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Andersson AC, Yun Z, Sperber GO, Larsson E, Blomberg J. ERV3 and related sequences in humans: structure and RNA expression. J Virol 2005; 79:9270-84. [PMID: 15994821 PMCID: PMC1168766 DOI: 10.1128/jvi.79.14.9270-9284.2005] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ERV3 locus at chromosome 7q11 is a much studied human endogenous retroviral (HERV) sequence, owing to an env open reading frame (ORF) and placental RNA and protein expression. An analysis of the human genome demonstrated that ERV3 is one of a group of 41 highly related elements (ERV3-like HERVs) which use proline, isoleucine, or arginine tRNA in their primer binding sites. In addition to elements closely related to ERV3, the group included the previously known retinoic acid-inducible element, RRHERVI, also referred to as HERV15, but was separate from the related HERV-E elements. The ERV3-like elements are defective. The only element with an ORF among gag, pro, pol, and env genes was the env ORF of the original ERV3 locus. A search in dbEST revealed ERV3 RNA expression in placenta, skin, carcinoid tumor, and adrenal glands. Expression was also studied with newly developed real-time quantitative PCRs (QPCR) of ERV3 and HERV-E(4-1) env sequences. Results from a novel histone 3.3 RNA QPCR result served as the expression control. QPCR results for ERV3 were compatible with previously published results, with a stronger expression in adrenal gland and placenta than in 15 other human tissues. The expression of the envelope (env) of ERV3 at chromosome 7q11 was also studied by using stringent in situ hybridization. Expression was found in corpus luteum, testis, adrenal gland, Hassal's bodies in thymus, brown fat, pituitary gland, and epithelium of the lung. We conclude that ERV3 env is most strongly expressed in adrenal and sebaceous glands as well as in placenta.
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Szabo S, Haislip AM, Garry RF. Of mice, cats, and men: Is human breast cancer a Zoonosis? Microsc Res Tech 2005; 68:197-208. [PMID: 16276516 DOI: 10.1002/jemt.20232] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Mouse mammary tumor virus (MMTV), a member of the betaretroviridae, is the most common cause of breast cancer (BC) in mice. MMTV is transmitted in mice both in the germline as endogenous proviruses and exogenously as infectious virions. Here, we review a variety of evidence accumulated for six decades that has suggested that a human homologue of MMTV may exist. The findings include recent studies from several independent laboratories that have detected sequences very closely related to MMTV in DNA isolated from human BC tumors. Other laboratories, however, have failed to detect the MMTV-related sequences in human DNA samples, and conclusive evidence for a human mammary tumor virus has been elusive. We also reviewed additional studies, suggesting that betaretroviruses are present in a much wider range of species than previously known, including rodents, felines, and primates. The observation that a subset of cats may be infected with a close homologue of MMTV may be of epidemiological significance for human BC. Cats may become infected by MMTV from mice, and in turn may transmit the virus to humans, possibly after selection for variants with an expanded host range.
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Affiliation(s)
- Sara Szabo
- Department of Pathology, Children's Hospital, New Orleans, Louisiana 70118, USA.
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Bannert N, Kurth R. Retroelements and the human genome: new perspectives on an old relation. Proc Natl Acad Sci U S A 2004; 101 Suppl 2:14572-9. [PMID: 15310846 PMCID: PMC521986 DOI: 10.1073/pnas.0404838101] [Citation(s) in RCA: 371] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Retroelements constitute a large portion of our genomes. One class of these elements, the human endogenous retroviruses (HERVs), is comprised of remnants of ancient exogenous retroviruses that have gained access to the germ line. After integration, most proviruses have been the subject of numerous amplifications and have suffered extensive deletions and mutations. Nevertheless, HERV-derived transcripts and proteins have been detected in healthy and diseased human tissues, and HERV-K, the youngest, most conserved family, is able to form virus-like particles. Although it is generally accepted that the integration of retroelements can cause significant harm by disrupting or disregulating essential genes, the role of HERV expression in the etiology of malignancies and autoimmune and neurologic diseases remains controversial. In recent years, striking evidence has accumulated indicating that some proviral sequences and HERV proteins might even serve the needs of the host and are therefore under positive selection. The remarkable progress in the analysis of host genomes has brought to light the significant impact of HERVs and other retroelements on genetic variation, genome evolution, and gene regulation.
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Nelson PN, Carnegie PR, Martin J, Davari Ejtehadi H, Hooley P, Roden D, Rowland-Jones S, Warren P, Astley J, Murray PG. Demystified. Human endogenous retroviruses. Mol Pathol 2003; 56:11-8. [PMID: 12560456 PMCID: PMC1187282 DOI: 10.1136/mp.56.1.11] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2002] [Indexed: 12/11/2022]
Abstract
Human endogenous retroviruses (HERVs) are a family of viruses within our genome with similarities to present day exogenous retroviruses. HERVs have been inherited by successive generations and it is possible that some have conferred biological benefits. However, several HERVs have been implicated in certain cancers and autoimmune diseases. This article demystifies these retroviruses by providing an insight into HERVs, their means of classification, and a synopsis of HERVs implicated in cancer and autoimmunity. Furthermore, the biological roles of HERVs are explored.
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Affiliation(s)
- P N Nelson
- School of Applied Sciences, Division of Biomedical Science and Biosciences, University of Wolverhampton, Wolverhampton WV1 1SB, UK.
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14
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Terzian C, Pélisson A, Bucheton A. Evolution and phylogeny of insect endogenous retroviruses. BMC Evol Biol 2001; 1:3. [PMID: 11591216 PMCID: PMC57737 DOI: 10.1186/1471-2148-1-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2001] [Accepted: 08/10/2001] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND The genome of invertebrates is rich in retroelements which are structurally reminiscent of the retroviruses of vertebrates. Those containing three open reading frames (ORFs), including an env-like gene, may well be considered as endogenous retroviruses. Further support to this similarity has been provided by the ability of the env-like gene of DmeGypV (the Gypsy endogenous retrovirus of Drosophila melanogaster) to promote infection of Drosophila cells by a pseudotyped vertebrate retrovirus vector. RESULTS To gain insights into their evolutionary story, a sample of thirteen insect endogenous retroviruses, which represents the largest sample analysed until now, was studied by computer-assisted comparison of the translated products of their gag, pol and env genes, as well as their LTR structural features. We found that the three phylogenetic trees based respectively on Gag, Pol and Env common motifs are congruent, which suggest a monophyletic origin for these elements. CONCLUSIONS We showed that most of the insect endogenous retroviruses belong to a major clade group which can be further divided into two main subgroups which also differ by the sequence of their primer binding sites (PBS). We propose to name IERV-K and IERV-S these two major subgroups of Insect Endogenous Retro Viruses (or Insect ERrantiVirus, according to the ICTV nomenclature) which respectively use Lys and Ser tRNAs to prime reverse transcription.
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Affiliation(s)
| | - Alain Pélisson
- IGH-CNRS, 141 rue de la Cardonille, Montpellier , France
| | - Alain Bucheton
- IGH-CNRS, 141 rue de la Cardonille, Montpellier , France
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Nilsson BO, Jin M, Andersson AC, Sundström P, Larsson E. Expression of envelope proteins of endogeneous C-type retrovirus on the surface of mouse and human oocytes at fertilization. Virus Genes 1999; 18:115-20. [PMID: 10403697 DOI: 10.1023/a:1008004332513] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Retrovirus genomes express, among other products, the envelop (env) proteins SU (gp70) and TM (p15E). They coexist at the viral surface membrane and are able to promote immunosuppression and membrane fusion. In mouse oocytes, endogeneous retroviruses (ERV) genomes are expressed at fertilization, and antigen epitopes of the Moloney murine leukemia virus (MuLV) env protein gp70 are recognized in the cytoplasm of the oocytes before but not after fertilization. By using a panel of monoclonal antibodies (mAbs) raised against env components, we checked with laser scanning confocal microscopy (LSCM) whether gp70 and p15E were expressed also on the oocyte surface membrane (oolemma). Since we found that both mouse and human unfertilized oocytes expressed these ERV proteins on the oolemma and that the expression enfeebled significantly after fertilization, we assume that ERV genomes could play a role at the sperm-egg binding and fusion.
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Affiliation(s)
- B O Nilsson
- Department of Anatomy, Biomedical Center, Uppsala, Sweden
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16
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Siray H, Ozel M, Jandrig B, Voronkova T, Jia W, Zocher R, Arnold W, Scherneck S, Krüger DH, Ulrich R. Capsid protein-encoding genes of hamster polyomavirus and properties of the viral capsid. Virus Genes 1999; 18:39-47. [PMID: 10334036 DOI: 10.1023/a:1008017201999] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
On the basis of its genome organization the hamster polyomavirus (HaPV) is closely related to the murine polyomavirus Py. But HaPV infection, in contrast to Py infection, gives rise to two different tumor types; depending on the hamster strain used for infection, HaPV induces either epitheliomas or lymphomas. Although the HaPV virions were shown to be similar to those of Py and SV40, more precise information about the structure and protein composition of the HaPV capsid was still missing. Here we describe the primary structure of the capsid protein-encoding HaPV genes and the structure and protein composition of the HaPV capsid. Virions isolated from epitheliomas in HaPV-infected hamsters were shown by electron microscopy to be spherical particles with the typical icosahedral structure of polyomaviruses. However, in contrast to the capsids of SV40 and Py, a T = 7 laevo symmetry of HaPV capsids was observed. Separation of HaPV virions in SDS polyacrylamide gels and Western blotting with VP1-specific antisera identified VP1 as the major capsid protein species corresponding in its molecular weight to the predicted value of 41.8 kDa. Because of the presence of two potential translational initiation sites in the VP1 gene, the N-terminal amino acid sequence of virion VP1 was determined and found to start at the second initiation site. The amino acid homologies of HaPV capsid proteins shared with Py varied between 65.5% (VP1), 45.4% (VP3) and 44.6% (VP2), whereas the homologies to the relevant proteins of other polyomaviruses were found to range between 49.6-57.9% for VP1 and 28.9-41% for VP2/VP3.
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Affiliation(s)
- H Siray
- Institute of Virology, Charité Medical School, Humboldt University, Berlin, Germany
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17
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Farson D, McGuinness R, Dull T, Limoli K, Lazar R, Jalali S, Reddy S, Pennathur-Das R, Broad D, Finer M. Large-scale manufacturing of safe and efficient retrovirus packaging lines for use in immunotherapy protocols. J Gene Med 1999; 1:195-209. [PMID: 10738568 DOI: 10.1002/(sici)1521-2254(199905/06)1:3<195::aid-jgm31>3.0.co;2-#] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND The use of gene modified T lymphocytes for immunotherapy in a cancer or AIDS clinical trial requires an efficient, safe ex vivo method for modification of these cells at manufacturing scale. Since retroviruses have been shown to be a moderately effective means of stably integrating therapeutic genes into T lymphocytes, we wanted to create packaging and producer cell lines that would produce replication competent retrovirus (RCR)-free supernatants, at large scale (> 200 l), and transduce with high efficiency. METHODS cDNA expression plasmids containing only coding sequences for gagpol or env were built and sequentially transfected into human 293 cells. Packaging and producer clones were characterized for stability, titer and RCR. A producer clone delivering chimeric immune receptors was scaled-up and supernatants used to transduce patient T lymphocytes for clinical studies. PCR and RT-PCR assays were utilized to evaluate the transmission of HERV-H sequences. Relative infectivity of producer clones pseudotyped with different envelopes was determined by transduction and RT assays. RESULTS RCR-free, human 293 split-genome packaging lines, pseudotyped with amphotropic, xenotropic, or 10A1 envelopes, were created. A CC49 zeta producer clone was scaled-up to 5 x 54 l lots and supernatants used to safely and efficiently transduce patient T lymphocytes with minimal ex vivo manipulation. While 293 cells express HERV-H mRNA, the transmission frequency in our packaging clones was less than 1 HERV-H sequence per 5 x 10(5) proviral integrations. Additionally, 10A1 and xenotropic packaging lines had higher infectivities than the amphotropic clone. CONCLUSION These packaging lines represent the safest configuration for the large-scale production of retroviral vectors, and are capable of producing high titer, RCR-free retroviral vector for large scale clinical use. While all three clones efficiently transduce human T lymphocytes, the 10A1 clone has the highest infectivity. These packaging cell lines will be valuable for use in human gene therapy protocols.
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Affiliation(s)
- D Farson
- Cell Genesys Inc., Foster City, CA 94404, USA
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18
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Knössl M, Löwer R, Löwer J. Expression of the human endogenous retrovirus HTDV/HERV-K is enhanced by cellular transcription factor YY1. J Virol 1999; 73:1254-61. [PMID: 9882329 PMCID: PMC103948 DOI: 10.1128/jvi.73.2.1254-1261.1999] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/1998] [Accepted: 10/15/1998] [Indexed: 11/20/2022] Open
Abstract
The human endogenous retrovirus HTDV/HERV-K, which resides in moderate copy numbers in the human genome, is expressed in a cell-type-specific manner, predominantly in teratocarcinoma cells. We have analyzed the regulatory potential of the 5' enhancer of the HERV-K long terminal repeat. Protein extracts of HERV-K-expressing teratocarcinoma cell lines (GH and Tera2) and nonexpressing HeLa and HepG2 cells form different protein complexes on the enhancer sequence as detected by electrophoretic mobility shift assays (EMSA). Using competition EMSAs, DNase I footprinting, and supershift experiments, we localized the binding site of these complexes to a 20-bp sequence within the enhancer and showed that the transcription factor YY1 is one component of the HERV-K enhancer complex. Replacement of the YY1 binding site with unrelated sequences reduced expression of the luciferase gene as a reporter in transient-transfection assays.
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Affiliation(s)
- M Knössl
- Virology Department, Paul-Ehrlich-Institut, D-63225 Langen, Germany
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19
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Roelofs H, van Gurp RJ, Oosterhuis JW, Looijenga LH. Detection of human endogenous retrovirus type K-specific transcripts in testicular parenchyma and testicular germ cell tumors of adolescents and adults: clinical and biological implications. THE AMERICAN JOURNAL OF PATHOLOGY 1998; 153:1277-82. [PMID: 9777959 PMCID: PMC1853062 DOI: 10.1016/s0002-9440(10)65672-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Testicular germ cell tumors (TGCTs) of adolescents and adults have been shown to contain proteins of the human endogenous retrovirus type K family. In a recent study, expression of these retroviral sequences was confirmed using in situ hybridization, which also showed expression in carcinoma in situ, the precursor of all TGCTs. Because of the clinical significance of a test for early diagnosis of TGCTs, we studied whether expression of human endogenous retrovirus type K genes could be an informative parameter. Therefore, we investigated TGCTs of various histologies and testicular parenchyma with and without carcinoma in situ using reverse transcription-polymerase chain reaction for expression of the gag, env, and prt genes. The gag and prt genes were expressed in all samples tested. The env transcripts were not found in TGCTs showing somatic differentiation only but could be detected in most normal testicular parenchyma samples. Therefore, detection of human endogenous retrovirus type K transcripts cannot be used for early diagnosis of TGCTs. Simultaneous expression of multiple gag sequences was found both in normal parenchyma and TGCTs, and we demonstrated that expression of gag sequences with an extra G, necessary to generate a functional protein, was not limited to TGCTs.
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Affiliation(s)
- H Roelofs
- Laboratory for Experimental Patho-Oncology, Daniel den Hoed Cancer Center, University Hospital Rotterdam, The Netherlands
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20
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Abstract
Human endogenous retroviruses (HERVs) have recently been suggested as mediators of normal biological processes such as cellular differentiation and regulation of gene expression. Moreover, a direct role for HERVs in pathogenesis and the development of disease is now better appreciated. Elucidation of the mechanisms regulating HERV biology should provide information about fundamental cellular activities and the pathogenesis of multifactorial diseases such as cancer and autoimmune disease. The importance of understanding the roles of HERVs is underscored by the recently obtained insight that activation of endogenous retroviruses poses potential risks following xenotransplantation and in gene therapy using retroviral vectors. Furthermore, HERV-encoded superantigens have recently been implicated as causes of autoimmune disease. This review discusses the established and possible biological roles of HERVs, and proposes hypotheses concerning their involvement as mediators of fundamental cellular responses. We propose that the evolutionary persistence of endogenous retroviruses in the genomes of eukaryotic cells reflects their indispensability in important normal functions in specialized cellular environments. HERVs can also be potentially hazardous through their involvement in the development of disease. In addition, the creation of new retroviruses can occur through recombination, between different HERVs and between HERVs and exogenous retroviruses.
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Affiliation(s)
- E Larsson
- Department of Genetics and Pathology, University of Uppsala, University Hospital, Sweden
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21
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Bebikhov DV, Postnov AY, Nikinenko TA. Role of retroposition in autoregulation of genomic processes (Do genes program the body and retroposons program the genome?). Bull Exp Biol Med 1998. [DOI: 10.1007/bf02446049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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22
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Willer A, Saussele S, Gimbel W, Seifarth W, Kister P, Leib-Mösch C, Hehlmann R. Two groups of endogenous MMTV related retroviral env transcripts expressed in human tissues. Virus Genes 1998; 15:123-33. [PMID: 9421877 DOI: 10.1023/a:1007910924177] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The human genome contains at least 50 copies of the human endogenous retrovirus K (HERV-K) family which is related to the mouse mammary tumor virus (MMTV). Some members have been shown to be transcriptionally active and to have large open reading frames. Using the RT-PCR method we have investigated the HERV-K env transcription pattern in several malignant tissues and in peripheral blood mononuclear cells PBMCs). Samples were derived from chronic myelogenous leukemia (CML), breast cancer, colon cancer, high and low grade non-Hodgkin's lymphomas, Hodgkin's disease, myelodysplastic syndrome, thyroid adenoma (TA) and from PBMCs of patients with breast cancer, gastric cancer, and of healthy individuals. We found abundant HERV-K env transcripts in all tissues under investigation. Using HERV-K 10 specific primers for amplification we detected in addition to transcripts with high homology to HERV-K 10 (ca. 96% homology on the amino acid level) also transcripts of low homology to HERV-K10 (ca. 71%). Interestingly, all solid tissues containing high percentages of malignant cells such as breast cancer, colon carcinoma, low and high grade non-Hodgkin's lymphomas showed exclusively HERV-K env related transcripts with low homology to HERV-K 10. In contrast, in samples containing only a low proportion of malignant cells or no malignant cells at all we observed both types of transcripts. Thus, our data suggest that the expression pattern of HERV-K elements in human cells is very heterogenous and subjected to a complex transcriptional regulation.
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Affiliation(s)
- A Willer
- III rd. Medizinische Klinik, Klinikum Mannheim, Universität Heidelberg, Germany
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23
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Tönjes RR, Limbach C, Löwer R, Kurth R. Expression of human endogenous retrovirus type K envelope glycoprotein in insect and mammalian cells. J Virol 1997; 71:2747-56. [PMID: 9060628 PMCID: PMC191397 DOI: 10.1128/jvi.71.4.2747-2756.1997] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The human endogenous retrovirus type K (HERV-K) family codes for the human teratocarcinoma-derived retrovirus (HTDV) particles. The existence of the envelope protein (ENV) of HERV-K encoded by the subgenomic env mRNA has not yet been demonstrated. To study the genetic requirements for successful expression of ENV, we have constructed a series of recombinant HERV-K env expression vectors for infection and transfection experiments in insect cells and mammalian cells, respectively. Six baculovirus constructs bearing full-length or truncated HERV-K env with or without homologous or heterologous signal peptides were used for infections of insect cells. All recombinant baculoviruses yielded ENV proteins with the expected molecular masses. The full-length 80- to 90-kDa HERV-K ENV protein including the cORF leader sequence was glycosylated in insect cells. In addition, the 14-kDa cORF protein was expressed due to splicing of the full-length env mRNA. The ENV precursor protein is not cleaved to the surface (SU) and transmembrane (TM) glycoproteins; it does not appear on the surface of infected insect cells and is not secreted into the medium. For ENV expression in COS cells, plasmid vectors harboring the cytomegalovirus immediate-early promoter/intron A element and the tissue plasminogen activator (t-PA) signal peptide or the homologous HERV-K signal peptide upstream of the env gene were employed. Glycosylated and uncleaved ENV was expressed as in GH teratocarcinoma cells but at higher levels. The heterologous t-PA signal sequence was instrumental for expression of HERV-K ENV on the cell surface. Hence, we have shown for the first time that the HERV-K env gene has the potential to be expressed as a full-length envelope protein with appropriate glycosylation. In addition, our data provide explanations for the lack of infectivity of HERV-K/HTDV particles.
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24
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Bengtsson A, Blomberg J, Nived O, Pipkorn R, Toth L, Sturfelt G. Selective antibody reactivity with peptides from human endogenous retroviruses and nonviral poly(amino acids) in patients with systemic lupus erythematosus. ARTHRITIS AND RHEUMATISM 1996; 39:1654-63. [PMID: 8843855 DOI: 10.1002/art.1780391007] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To investigate antibody responses to a broad panel of peptides derived from human endogenous retroviruses (HERVs) among unselected patients with systemic lupus erythematosus (SLE). METHODS In sera obtained from 69 patients with SLE and healthy blood donors, immunoassay was used to measure levels of antibody against synthetic peptides derived from HERVs, exogenous retroviruses, and nonviral poly(amino acids). RESULTS Measurement by immunoassay revealed increased frequencies of antiretroviral antibodies against 2 peptides derived from the env gene of the type C-like class, which includes ERV-9 and HERV-H, and against 2 peptides from the gag region of human T lymphotropic virus type I-related endogenous sequence 1, in patients with SLE. Antibodies to 2 nonviral peptides, polyhistidine and polyproline, were also overrepresented in patient sera. In 1 patient, longitudinal data obtained over a period of 12 years indicated that the concentrations of certain antiretroviral antibodies varied according to disease activity. CONCLUSION Reactivity to certain type C HERV-derived antigens was found among patients with SLE. This reactivity could be explained by increased exposure to cross-reactive epitopes from essentially complete type C HERVs.
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25
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Rasmussen HB, Heltberg A, Christensen K, Clausen J. Possible association between multiple sclerosis and the human T cell leukemia virus (HTLV)-related endogenous element, HRES-1. Mult Scler 1996; 2:133-6. [PMID: 9345377 DOI: 10.1177/135245859600200303] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In the present study we searched for an association between the human endogenous retroviral element HRES-1 and multiple sclerosis (MS). Fragments of this endogenous retrovirus were amplified for subsequent examination by single strand conformational analysis. We did not find HRES-1 markers exclusively linked with MS and only the two already known polymorphisms, which define three alleles of HRES-1, were detected. However, we found a significant difference in the distribution of these alleles between a group of 87 MS patients and a control group of 158 healthy individuals (P = 0.014). There were no differences in the distribution of the HRES-1 allelic forms between MS patients with a relapsing-remitting course and patients with chronic progressive MS. Our results provide evidence of an association between HRES-1 and MS. Possible explanations for this are discussed.
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Affiliation(s)
- H B Rasmussen
- Institute of Life Sciences and Chemistry, Roskilde University, Denmark
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26
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Larsson E, Venables PJ, Andersson AC, Fan W, Rigby S, Botling J, Oberg F, Cohen M, Nilsson K. Expression of the endogenous retrovirus ERV3 (HERV-R) during induced monocytic differentiation in the U-937 cell line. Int J Cancer 1996; 67:451-6. [PMID: 8707424 DOI: 10.1002/(sici)1097-0215(19960729)67:3<451::aid-ijc23>3.0.co;2-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
ERV3 (HERV-R) is a complete human endogenous retrovirus located on the long arm of chromosome 7. LTR-env-gene-spliced mRNA of 9 and 3.5 Kb is widely expressed in human tissues and cells, but gag-pol mRNA has not been found. Further, the env gp70 gene contains an open reading frame throughout its length and its expression has recently been detected as a full-length protein. The highest expression of ERV3 detected so far is in placenta and the lowest in cytotrophoblasts and choriocarcinoma cell lines. In this report we have studied ERV3 mRNA and protein expression in the human monoblastic cell line U-937 during differentiation into monocytes/macrophages. Differentiation of U-937 cells was induced by 1,25a-dihydroxyvitamin D3 (vitD3), retinoic acid (RA), gamma interferon (IFN-gamma) and phorbol-myristate-acetate (PMA-TPA). The expression of ERV3 env mRNA was found to be differentiation-associated, with high expression detected in the late stages of monocytic development. Using TPA, the expression of ERV3 env was detected as 9- and 3.5-kb transcripts by Northern blotting, as mRNA by in situ hybridization and as a cytoplasmic 65-kDa protein by immunofluorescence and Western blots. Low levels of basal expression were found, with up-regulation of both message and protein at 24 to 48 hr after addition of TPA. Induction with vitD3, IFN-gamma and RA produced higher levels of mRNA at earlier time points. It is concluded that the U-937 cell line represents an excellent model system for further studies to study the relationship between ERV3 expression and cellular differentiation.
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Affiliation(s)
- E Larsson
- Department of Pathology, Uppsala University Hospital, Sweden
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27
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Löwer R, Löwer J, Kurth R. The viruses in all of us: characteristics and biological significance of human endogenous retrovirus sequences. Proc Natl Acad Sci U S A 1996; 93:5177-84. [PMID: 8643549 PMCID: PMC39218 DOI: 10.1073/pnas.93.11.5177] [Citation(s) in RCA: 493] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Human endogenous retroviruses (HERVs) are very likely footprints of ancient germ-cell infections. HERV sequences encompass about 1% of the human genome. HERVs have retained the potential of other retroelements to retrotranspose and thus to change genomic structure and function. The genomes of almost all HERV families are highly defective. Recent progress has allowed the identification of the biologically most active family, HTDV/HERV-K, which codes for viral proteins and particles and is highly expressed in germ-cell tumors. The demonstrable and potential roles of HTDV/HERV-K as well as of other human elements in disease and in maintaining genome plasticity are illustrated.
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Affiliation(s)
- R Löwer
- Paul-Ehrlich-Institut, Langen, Germany
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28
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Abstract
Both genetic and environmental factors appear to contribute to the causation of schizophrenia. Evidence indicating that fetal development is disrupted in schizophrenia and the finding of an excess of winter births among schizophrenic patients have led to continued speculation that an intrauterine viral infection may cause developmental lesions, genetic mutations, or persistent infections that lead to schizophrenia. Certain unique characteristics of the retroviruses render them plausible as candidate "schizoviruses" and the involvement of an endogenous retrovirus would be compatible with some of the puzzling epidemiological findings in schizophrenia. Reverse transcriptase (RT) is a retrovirally encoded enzyme essential for retroviral integration into host DNA. While attempts to detect retroviral infections by measuring RT activity in the peripheral lymphocytes and serum of schizophrenic patients have been unsuccessful, such negative findings may simply mean that the virus is not active in peripheral lymphocytes. A more sensitive and comprehensive approach to detect a retrovirus is to search the genomes of schizophrenic patients directly for the presence of retroviral DNA sequences encoding RT and one possible approach is described.
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Affiliation(s)
- R L O'Reilly
- Department of Psychiatry, University of Western Ontario, London, Canada
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29
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Geley S, Fiegl M, Hartmann BL, Kofler R. Genes mediating glucocorticoid effects and mechanisms of their regulation. Rev Physiol Biochem Pharmacol 1996; 128:1-97. [PMID: 8791720 DOI: 10.1007/3-540-61343-9_7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- S Geley
- Institute for General and Experimental Pathology, University of Innsbruck Medical School, Austria
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30
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Seifarth W, Skladny H, Krieg-Schneider F, Reichert A, Hehlmann R, Leib-Mösch C. Retrovirus-like particles released from the human breast cancer cell line T47-D display type B- and C-related endogenous retroviral sequences. J Virol 1995; 69:6408-16. [PMID: 7545247 PMCID: PMC189540 DOI: 10.1128/jvi.69.10.6408-6416.1995] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The human mammary carcinoma cell line T47-D releases retrovirus-like particles of type B morphology in a steroid-dependent manner (I. Keydar, T. Ohno, R. Nayak, R. Sweet, F. Simoni, F. Weiss, S. Karby, R. Mesa-Tejada, and S. Spiegelman, Proc. Natl. Acad. Sci. USA 81:4188-4192, 1984). Furthermore, reverse transcriptase (RT) activity is found to be associated with particle preparations. Using a set of degenerate primers derived from a conserved region of retroviral pol genes, we repeatedly amplified three different retroviral sequences (MLN, FRD, and FTD) from purified T47-D particles in several RT-PCR experiments. Screening of a human genomic library and Southern blot analysis revealed that these sequences are of endogenous origin. ERV-MLN represents a multicopy family of human endogenous retroviral elements (HERVs) with two closely related copies and up to 20 more distantly related members. In contrast, ERV-FRD and ERV-FTD comprise only one copy and five to seven related elements per haploid human genome. DNA sequence analysis of the proviral pol region of ERV-MLN revealed an uninterrupted stretch of 241 amino acids that shows 65% identity with the RT of the type B-related HERV designated HERV-K10. ERV-FRD and ERV-FTD are defective type C-related HERVs. The pol gene of ERV-FRD displays a nucleotide homology of 54% to the gibbon ape leukemia virus, and the pol gene of ERV-FTD is about 67% homologous to members of the RTVL-I family of HERVs. Our results thus indicate that the retroviral particles released by the breast cancer cell line T47-D are probably generated by complementation of several endogenous proviruses and can package retroviral transcripts of different origins.
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Affiliation(s)
- W Seifarth
- III Medizinische Klinik, Klinikum Mannheim, Universität Heidelberg, Mannheim, Germany
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31
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Durgam VR, Easton JA, Surya R, Tekmal RR. Structure of the int-5, a novel MMTV integration genomic locus containing mouse early transposon LTR homology region. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1263:89-92. [PMID: 7632740 DOI: 10.1016/0167-4781(95)00093-v] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Previous studies have reported the cloning and identification of the int-5, a novel mouse mammary tumor virus (MMTV) integration locus involved in mammary tumorigenesis. Here we report the characterization of the 5.5 kb region from this novel MMTV integration site. Our results show that the region after the MMTV integration site, a 258 bp sequence is homologous (100%) to the mouse early transposon (mETn) long-terminal repeat and other sequences of the this transposon are not present in the 5.5 kb region. Our results also show for the first time the tumor specific expression of mETn and expression of the region downstream of the MMTV integration site that is homologous to mETn-LTR in D2 mammary tumors.
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Affiliation(s)
- V R Durgam
- Department of Obstetrics and Gynecology, University of Texas Health Science Center at San Antonio 78284-7836, USA
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32
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Abstract
Retroelements comprise a substantial portion of the human genome. Their large number and ubiquitous distribution has led scientists to speculate about their evolutionary origin and their biological functions. Human endogenous retroviruses and their retrotransposon relatives represent a reservoir of possibly pathogenic retroviral genes that may be activated spontaneously or by environmental conditions. They can act as insertion mutagens and activate or inactivate cellular genes, or may be involved in chromosome aberrations by recombination of related elements on different chromosomal locations. Retroviral gene products themselves may also be pathogenic and, for example, could be implicated in the development of tumors and autoimmune diseases. On the other hand, endogenous retroviral elements and nonviral retroposons are thought to have played an important role in shaping the genomes of vertebrates by intracellular transposition events and by generating hot spots of recombination. In the course of time, some of these elements have acquired cellular functions, such as, for instance, in the regulation of gene expression. Therefore, the role of human endogenous retroviruses and retroposons in biological processes is currently a subject of great interest.
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Affiliation(s)
- C Leib-Mösch
- III. Medizinische Klinik, Klinikum Mannheim, Universität Heidelberg, Mannheim, Federal Republic of Germany
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33
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Takeuchi K, Katsumata K, Ikeda H, Minami M, Wakisaka A, Yoshiki T. Expression of endogenous retroviruses, ERV3 and lambda 4-1, in synovial tissues from patients with rheumatoid arthritis. Clin Exp Immunol 1995; 99:338-44. [PMID: 7882554 PMCID: PMC1534193 DOI: 10.1111/j.1365-2249.1995.tb05555.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We addressed the question of whether or not expression of human endogenous retroviruses (ERV), ERV3 and lambda 4-1, is related to the pathogenesis of rheumatoid arthritis (RA). In genomic Southern hybridization, there were no significant differences between RA patients and healthy volunteers with regard to frequencies of restriction fragment length polymorphism (RFLP) patterns, for either ERV3 or lambda 4-1. By Northern blot analysis using fresh synovial tissues, cultured synovial cells, and peripheral blood mononuclear cells (PBMC) from patients with RA, we noted two molecular species of ERV3 mRNAs of 3.5 kb and 9.0 kb sizes, and one single molecular species of lambda 4-1 mRNAs of 4.2 kb size. The expression was detected not only in RA patients but also in synovial cells from osteoarthritis (OA) as a non-RA control and PBMC from healthy volunteers, and was not related to RA activities or treatments. Although ERV3 and lambda 4-1 expression may not be directly associated with the pathogenic pathway of RA, the possibility exists that human ERV may have a causative role in autoimmune diseases, including RA. We also examined the effect of cytokines on the transcriptional regulation of ERV3. Although the level of ERV3 expression in cultured synovial cells did not change with IL-1 beta treatment, the level for cultured proximal tubular epithelial cells (hKEC) was up-regulated.
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Affiliation(s)
- K Takeuchi
- Department of Pathology, Hokkaido University School of Medicine, Sapporo, Japan
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34
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Sauter M, Schommer S, Kremmer E, Remberger K, Dölken G, Lemm I, Buck M, Best B, Neumann-Haefelin D, Mueller-Lantzsch N. Human endogenous retrovirus K10: expression of Gag protein and detection of antibodies in patients with seminomas. J Virol 1995; 69:414-21. [PMID: 7983737 PMCID: PMC188589 DOI: 10.1128/jvi.69.1.414-421.1995] [Citation(s) in RCA: 151] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The human endogenous retrovirus K10 (HERV-K10) has been identified in the human genome by its homology to retroviruses of other vertebrates (M. Ono, T. Yasunaga, T. Miyata, and H. Ushikubo, J. Virol. 60:589-598, 1986). Using PCR amplification, DNA cloning, sequencing, and procaryotic expression, we were able to demonstrate that HERV-K10 encodes a 73-kDa protein which was processed by a HERV-K10-encoded protease to yield proteins p22/p26, p30, and p15/16. Analysis of the teratocarcinoma cell line Tera 1 or tumor tissues by immunoblotting demonstrated that the 80-kDa polyprotein of HERV-K10 gag and a processed protein of 39 kDa were expressed. In addition, a major protein of 39 kDa and additional species of 30, 22, 19, and 17 kDa could be detected in the supernatant of Tera 1 cells, suggesting that HERV-K10 Gag proteins are either secreted or processed to probably incomplete viral particles. In addition, the gag gene of HERV-K10 was expressed in the baculovirus system. Using this recombinant system to test antisera from patients with different diseases and healthy individuals, we were able to detect antibodies against the N-terminal part of HERV-K10 Gag in 2 to 4% of groups of tumor patients with titers ranging between 1:80 and 1:640, while approximately 0.1 to 0.5% of healthy individuals exhibited antibodies with lower titers. In contrast, patients with seminoma had antibody titers in the range of 1:2,560 at the time when the tumor was detected. Immunohistochemistry using specific rabbit sera or monoclonal antibodies against HERV-K10 Gag revealed that the Gag protein is expressed in the cytoplasm of the tumor cells. Furthermore, an 80-kDa protein corresponding to the HERV-K10 Gag polyprotein could be detected in tumor biopsies. For the first time, these data indicate that HERV-K10 Gag proteins are synthesized in seminoma cells and tumors exhibit relatively high antibody titers against Gag. So far, no information on which role HERV-K10 plays in the development of this tumor exists.
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Affiliation(s)
- M Sauter
- Abteilung Virologie, Universitätkliniken des Saarlandes, Homburg/Saar, Germany
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35
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Schuurman HJ, Joling P, van Wichen DF, Rademakers LH, Broekhuizen R, de Weger RA, van den Tweel JG, Goudsmit J. Follicular dendritic cells and infection by human immunodeficiency virus type 1--a crucial target cell and virus reservoir. Curr Top Microbiol Immunol 1995; 201:161-88. [PMID: 7587350 DOI: 10.1007/978-3-642-79603-6_10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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36
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Nelson PN, Lever AM, Bruckner FE, Isenberg DA, Kessaris N, Hay FC. Polymerase chain reaction fails to incriminate exogenous retroviruses HTLV-I and HIV-1 in rheumatological diseases although a minority of sera cross react with retroviral antigens. Ann Rheum Dis 1994; 53:749-54. [PMID: 7826136 PMCID: PMC1005456 DOI: 10.1136/ard.53.11.749] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVES To investigate the presence of antibodies to HTLV and HIV retroviral antigens in the rheumatological diseases rheumatoid arthritis (RA), polymyositis/dermatomyositis (PM/DM), primary Sjögren's syndrome (pSS), and systemic lupus erythematosus (SLE), and to use polymerase chain reaction (PCR) to seek these exogenous retroviruses in proviral form in cellular DNA from these patients. METHODS Thirty patients with active RA, 13 with PM, 14 with pSS and five with SLE were recruited and their sera tested for antibodies to HTLV-I in enzyme linked immunosorbent assay (ELISA) and Western blot analysis. Seropositivity to HIV-1 was also sought. DNA was extracted from peripheral blood lymphocytes, synovial tissue and muscle biopsies and tested by polymerase chain reaction using consensus primers for HTLV-I and HIV-1. RESULTS In HTLV-I ELISA, nine rheumatological sera (4/30 RA, 3/13 PM/DM and 2/5 SLE patients) were considered positive; 14 from pSS patients and 30 from normal subjects were negative. In a control group which included osteoarthritis, Crohn's disease and bacterial endocarditis patients, only two of 80 proved positive in this system. Validation of these sera by Western blotting generally revealed weak reactivity against a variety of HTLV-I antigens. PCR of genomic DNA derived from patients' peripheral blood mononuclear cells did not reveal the presence of HTLV-I and HIV-1 target sequences. CONCLUSIONS This study shows that PCR precludes HTLV-I and HIV-1 infection as causative agents in these rheumatological diseases although a minority of patients possess antibodies that are weakly cross-reactive with retroviral antigens.
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Affiliation(s)
- P N Nelson
- Division of Immunology, St George's Hospital Medical School, London, United Kingdom
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37
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Abstract
In autoimmune rheumatic diseases, retroviruses have been repeatedly discussed as important etiologic factors. However, despite a considerable amount of indirect evidence that retroviruses might indeed be involved in triggering or perpetuating autoimmune rheumatic diseases, clear cut direct evidence is still missing. Studies on arthropathies associated with HIV-1 or HTLV-1 infection as well as new experimental animal models like the Tax transgene mice and new data from the MLR/lpr mouse model might help to answer the questions how and by what mechanisms retroviral infection may lead to autoimmune rheumatic diseases. From data obtained in the MLR/lpr mouse it seems obvious that a potential link of retroviruses, apoptosis and autogenes to autoimmune diseases opens exciting new approaches to the study of rheumatic disease pathogenesis.
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Affiliation(s)
- J R Kalden
- Department of Internal Medicine III, University Erlangen-Nuremberg, Germany
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38
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Blomberg J, Nived O, Pipkorn R, Bengtsson A, Erlinge D, Sturfelt G. Increased antiretroviral antibody reactivity in sera from a defined population of patients with systemic lupus erythematosus. Correlation with autoantibodies and clinical manifestations. ARTHRITIS AND RHEUMATISM 1994; 37:57-66. [PMID: 7510483 DOI: 10.1002/art.1780370109] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
OBJECTIVE The implied role of retroviruses in the pathogenesis of murine systemic lupus erythematosus (SLE) led us to study antiretroviral antibodies in a population-based SLE cohort. METHODS Immunoassays using whole virus and synthetic peptides were performed on sera from 72 patients with SLE and 88 control subjects. RESULTS Reactions with whole baboon endogenous virus occurred more frequently in patients with SLE, and correlated with the presence of anti-RNP and anti-Sm. Some retroviral env and gag peptides, several of which were similar to U1 small nuclear RNP, reacted more strongly in patients with SLE, and their presence was correlated with discoid rash, hematologic disorder, and other symptoms. CONCLUSION These results provide circumstantial evidence for involvement of retroviruses in the pathogenesis of human SLE; further studies should be carried out using other techniques for measurement of retroviral expression.
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Affiliation(s)
- J Blomberg
- Department of Medical Microbiology, University of Lund, Sweden
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39
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Asch BB, Asch HL, Stoler DL, Anderson GR. De-regulation of endogenous retrotransposons in mouse mammary carcinomas of diverse etiologies. Int J Cancer 1993; 54:813-9. [PMID: 8392034 DOI: 10.1002/ijc.2910540516] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Of the several families of endogenous retrovirus-like elements present in the mouse genome, only mouse mammary tumor virus has been analyzed for its role in mammary carcinogenesis. Very little is known about the expression and activities of other retro-elements in normal and malignant mammary epithelium. We have begun investigating the possible involvement of the 3 retrotransposons, intracisternal A particles (IAPs), murine-leukemia-virus-related (MuLVr) elements, and VL30 sequences, in neoplastic progression of the mammary gland in BALB/c mice. The purpose of the present study was to determine which of these elements was active in primary mammary carcinomas induced by chemical, hormonal and viral agents. Each of these cancers had aberrant expression of at least one of the latter retrovirus-like components. IAP and/or MuLVr sequences were over-expressed 3 to 100-fold in most of the tumors as compared with normal mammary tissue, whereas VL30 expression was markedly decreased by 5- to 35-fold in almost all of the neoplasms. Our results thus demonstrate that substantial changes in the expression of one or more of these 3 families of endogenous retrotransposons are triggered during mouse mammary tumorigenesis, regardless of etiology. Direct involvement of IAPs and MuLVr elements in neoplastic progression by transposition and insertional mutagenesis in the genome of several hematopoietic cell types has already been demonstrated. Their elevated expression in many mammary carcinomas suggests that these retrotransposons may also be potential participants in some pathways of mouse mammary carcinogenesis.
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Affiliation(s)
- B B Asch
- Department of Experimental Pathology, Roswell Park Cancer Institute, Buffalo, NY 14263
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40
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Temin HM. A proposal for a new approach to a preventive vaccine against human immunodeficiency virus type 1. Proc Natl Acad Sci U S A 1993; 90:4419-20. [PMID: 8506281 PMCID: PMC46522 DOI: 10.1073/pnas.90.10.4419] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) is a more complex retrovirus, coding for several accessory proteins in addition to the structural proteins (Gag, Pol, and Env) that are found in all retroviruses. More complex retroviruses have not been isolated from birds, and simpler retroviruses have not been isolated from humans. However, the proviruses of many endogenous simpler retroviruses are present in the human genome. These observations suggest that humans can mount a successful protective response against simpler retroviruses, whereas birds cannot. Thus, humans might be able to mount a successful protective response to infection with a simpler HIV-1. As a model, a simpler bovine leukemia virus which is capable of replicating has been constructed; a simpler HIV-1 could be constructed in a similar fashion. I suggest that such a simpler HIV-1 would be a safe and effective vaccine against HIV-1.
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Affiliation(s)
- H M Temin
- McArdle Laboratory, Madison, WI 53706
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41
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Löwer R, Boller K, Hasenmaier B, Korbmacher C, Müller-Lantzsch N, Löwer J, Kurth R. Identification of human endogenous retroviruses with complex mRNA expression and particle formation. Proc Natl Acad Sci U S A 1993; 90:4480-4. [PMID: 8506289 PMCID: PMC46535 DOI: 10.1073/pnas.90.10.4480] [Citation(s) in RCA: 201] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Retroviruses comprise strains with considerable disease potential in animals and humans. In addition to exogenous strains transmitted horizontally, endogenous proviruses are transmitted through the germ line. Some of these endogenous retroviruses can be pathogenic in mice and possibly in other animal species. They may also be considered as mobile genetic elements with the potential to produce mutations. In humans, genomic DNA contains numerous endogenous retroviral sequences detected by their partial relatedness to animal retroviruses. However, all proviruses sequenced so far have been found to be defective. In this communication, we describe the expression of a family of human endogenous retrovirus sequences (HERV-K) in GH cells, a teratocarcinoma cell line producing the human teratocarcinoma-derived retrovirus (HTDV) particles previously described by us. Four viral mRNA species could be identified, including a full-length mRNA. The other three subgenomic mRNAs are generated by single or double splicing events. This expression pattern is reminiscent of the more complex control of virus gene regulation observed, for example, with lenti- or spumavirus strains, although HERV-K shows no sequence homology to human T-lymphotropic virus or human immunodeficiency virus. Sequence analysis of expressed HERV-K genomes revealed non-defective gag genes, a prerequisite for particle formation. Open reading frames were also observed in pol and env. Antisera raised against recombinant gag proteins of HERV-K stained HTDV particles in immunoelectron microscopy, linking them to the HERV-K family.
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Affiliation(s)
- R Löwer
- Paul Ehrlich Institute, Langen, Federal Republic of Germany
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42
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Gay S, Gay RE, Koopman WJ. Molecular and cellular mechanisms of joint destruction in rheumatoid arthritis: two cellular mechanisms explain joint destruction? Ann Rheum Dis 1993; 52 Suppl 1:S39-47. [PMID: 8481058 PMCID: PMC1035025 DOI: 10.1136/ard.52.suppl_1.s39] [Citation(s) in RCA: 190] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- S Gay
- Department of Medicine, University of Alabama, Birmingham 35294-0006
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Lindeskog M, Medstrand P, Blomberg J. Sequence variation of human endogenous retrovirus ERV9-related elements in an env region corresponding to an immunosuppressive peptide: transcription in normal and neoplastic cells. J Virol 1993; 67:1122-6. [PMID: 8419641 PMCID: PMC237471 DOI: 10.1128/jvi.67.2.1122-1126.1993] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Evolutionarily conserved sequences corresponding to an immunosuppressive region in retroviral transmembrane proteins were amplified by the polymerase chain reaction from human genomic DNA and reverse-transcribed RNA from one glioma, three pieces of macroscopically normal brain tissue, kidney, lymphocytes, cultured embryonic lung cells, and a rhabdomyosarcoma cell line. Amplification products (125 bp) from DNA and RNA from the glioma and RNA from one normal piece of brain tissue were cloned and sequenced (45 clones). A variety of sequences similar to ERV9 (75 to 93%) were identified. Amplification products were immobilized on nylon filters and hybridized to four different synthetic oligonucleotides derived from the sequenced clones. Sequences without the stop codon seen in ERV9 in this region, possibly encoding functional immunosuppressive proteins, were present in RNA amplificates from all samples. The various cell types showed different hybridization patterns with the four probes. The open reading frame sequences were identified in genomic Southern blots, one probe detecting about 10 copies and another detecting a single copy. Northern (RNA) blots of mRNA from various normal human tissues revealed 2.5-kb (e.g., lung) and 10-kb (e.g., placenta) transcripts hybridizing to one of the probes.
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Affiliation(s)
- M Lindeskog
- Department of Medical Microbiology, University of Lund, Sweden
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44
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Feuchter-Murthy AE, Freeman JD, Mager DL. Splicing of a human endogenous retrovirus to a novel phospholipase A2 related gene. Nucleic Acids Res 1993; 21:135-43. [PMID: 8382789 PMCID: PMC309075 DOI: 10.1093/nar/21.1.135] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
As part of an investigation into the effects of endogenous retroviruses on adjacent genes, we have isolated a cDNA clone derived from the human teratocarcinoma cell line NTera2D1 representing a chimeric transcript in which an endogenous retrovirus-like element, RTVL-H, has been spliced to downstream cellular sequences. The 5' terminus of this clone, termed AF-5, occurs one bp downstream of the predicted transcriptional start site in the RTVL-H long terminal repeat (LTR). AF-5 contains an open reading frame of 689 amino acids beginning within RTVL-H sequences that has two domains of homology with phospholipase A2 (PLA2). These domains, of approximately 120 amino acids each, are 30-38% identical to secreted PLA2s and contain sequence features of both group I and II enzymes. The corresponding AF-5 transcript is 2.5 kb and is derived from a single copy novel gene termed PLA2L. Southern analysis indicates that the RTVL-H element is normally present in human DNA upstream of the PLA2L gene. RTVL-H/PLA2L chimeric transcripts were detected in two independent teratocarcinoma cell lines but not in several other cell lines or primary human tissues. Characterization of additional cDNA clones and PCR analysis indicates that multiple RTVL-H/PLA2L alternatively spliced transcripts are expressed. No evidence has been found for transcription from a non-LTR promoter. These findings strongly suggest that the endogenous LTR promotes expression of the human PLA2L gene in teratocarcinoma cells.
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45
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46
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Plagemann PG, Moennig V. Lactate dehydrogenase-elevating virus, equine arteritis virus, and simian hemorrhagic fever virus: a new group of positive-strand RNA viruses. Adv Virus Res 1992; 41:99-192. [PMID: 1315480 PMCID: PMC7131515 DOI: 10.1016/s0065-3527(08)60036-6] [Citation(s) in RCA: 230] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The last comprehensive reviews of nonarbotogaviruses included discussions on pestiviruses, rubella virus, lactate dehydrogenase-elevating virus (LDV), equine arteritis virus (EAV), simian hemorrhagic fever virus (SHFV), cell fusion agent, and nonarboflaviviruses. The inclusion of all these viruses in the family Togaviridae was largely based on the similarities in morphological and physical–chemical properties of these viruses, and in the sizes and polarities of their genomes. In the intervening years, considerable new information on the replication strategies of these viruses and the structure and organization of their genomes has become available that has led to the reclassification or suggestions for reclassification of some of them. The replication strategy of EAV resembles that of the coronaviruses, involving a 3'-coterminal nested set of mRNAs. Therefore, EAV has been suggested to be included in a virus superfamily, along with coronaviruses and toroviruses. Recent evidence indicates that LDV not only resembles EAV in morphology, virion and genome size, and number and size of their structural proteins, but also in genome organization and replication via a 3'-coterminal set of mRNAs. SHFV, although not fully characterized, exhibits properties resembling those of LDV and EAV, and the recent evidence suggest that it may possess the same genome organization as these viruses. The three viruses may, therefore, represent a new family of positive-strand RNA viruses and are reviewed together in this chapter. In this chapter, emphasis is on the recent information concerning their molecular properties and pathogenesis in vitro and in vivo and on the host immune responses to infections by these viruses.
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Affiliation(s)
- P G Plagemann
- Department of Microbiology, University of Minnesota Medical School, Minneapolis 55455
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47
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Abstract
Transposable elements, and retroviral-like elements in particular, are a rich potential source of genetic variation within a host's genome. Many mutations of endogenous genes in phylogenetically diverse organisms are due to insertion of elements that affect gene expression by altering the normal pattern of regulation. While few such associations are known to have been maintained over time, two recently elucidated examples suggest transposable elements may have a significant impact in evolution of gene expression. The first example, concerning the mouse sex-limited protein (Slp), clearly establishes that ancient retroviral enhancer sequences now confer hormonal dependence on the adjacent gene. The second example shows that within the human amylase gene family, salivary specific expression has arisen due to inserted sequences, deriving perhaps from a conjunction of two retrotransposable elements.
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Affiliation(s)
- D M Robins
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor 48109
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48
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Prayoonwiwat N, Pease LR, Rodriguez M. Human T-cell lymphotropic virus type I sequences detected by nested polymerase chain reactions are not associated with multiple sclerosis. Mayo Clin Proc 1991; 66:665-80. [PMID: 2072754 DOI: 10.1016/s0025-6196(12)62078-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The hypothesis that human T-cell lymphotropic virus type I (HTLV-I) infection is associated with multiple sclerosis (MS) was tested by using primers specific to gag and pol regions of HTLV-I in an analysis that used polymerase chain reactions. No amplification of DNA from patients with MS was detected with primers for either region. After application of a more sensitive scheme with use of nested primers, however, half the samples, including patients with MS and normal control subjects, were found to contain pol DNA sequences. No sequences related to the HTLV-I gag region were detected among patients with MS by using nested primers. Sequences of the amplified HTLV-I pol genomes were determined. Regardless of their origin (MS or normal control), the pol region sequences were similar to HTLV-I sequences reported by other investigators. We conclude that HTLV-I does not have a distinct association with MS, but HTLV-I-related sequences, although in extremely low copy number, may be present in human genomes.
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Affiliation(s)
- N Prayoonwiwat
- Department of Neurology, Mayo Clinic, Rochester, MN 55905
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49
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Abstract
Endogenous DNA sequences related to retroviruses are probably present in all primates. By using approaches based on the polymerase chain reaction, two separate studies have revealed the evolutionary history of some of these sequences. In the first study, a retrovirus-like reverse transcriptase (RT) sequence homologous to that of Baboon endogenous virus (BaEV) has been identified in both Old World monkeys and African apes, but not in humans or Asian apes. This RT sequence is highly conserved at the amino acid level, but not the nucleotide level, in the baboon, African green monkey, Java macaque, chimpanzee, and gorilla. The patterns of nucleotide substitution indicate functional conservation and suggest that this RT sequence was present in the primate germline before apes and Old World monkeys diverged about 30 million years ago. In the second study, a comparison of endogenous proviral DNAs and their adjacent sequences has been used to analyze the evolutionary history of three previously reported human endogenous retroviruses, HERV-E(4.14), HERV-R(3), and HERV-Ia. It is shown that these retroviruses have also been resident in the primate line since before the ape-Old World monkey divergence. The implications of the presence of functionally conserved RT genes in the germlines of primates, and the potential for using integration sites as tools for analyzing phylogenetic relationships among primates and their retroviruses, are discussed.
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Affiliation(s)
- A Shih
- Department of Biochemistry, New York University School of Medicine, New York 10016
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50
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Neumüller M, Karlsson A, Lennerstrand J, Källander CF, Holmberg V, Långström-Persson U, Thorstensson R, Sandström E, Gronowitz JS. HIV reverse transcriptase inhibiting antibodies detected by a new technique: relation to p24 and gp41 antibodies, HIV antigenemia and clinical variables. J Med Virol 1991; 34:55-63. [PMID: 1715898 DOI: 10.1002/jmv.1890340110] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A new assay for HIV reverse transcriptase activity inhibiting antibodies (RTI-ab) was used for the analysis of a large collection of sera sampled before and after confirmation of HIV infection. In this assay HIV-RT was preincubated with diluted serum, after which residual RT activity was determined by a technique using a template coupled to macrobeads and 125I-lodo-deoxyuridine-triphosphate as the tracer-substrate. Of the 936 sera analysed, 818 were found positive for RTI-ab, and 824 were positive in Western blot (Wb). The prevalence of RTI-ab compared to Wb was therefore 99.3%. The corresponding figure for 930 sera analysed for envelope-ab, i.e., gp41-ab, was 823 positive, and of these 930 sera 815 were Wb positive, giving a comparative prevalence of 101%. In contrast, only 678 samples of 993 analyzed for core ab, i.e., p24, were positive, giving a prevalence of 77.0% as 880 of these samples were Wb positive. Thus, RTI-ab was as prevalent as gp41-ab, and although the analyses of RTI-ab amounts in different stages showed decreasing levels in stage IV compared to stages II or III, all of the sera except 1 were found positive in stages III and IV. Further, it was found that both the few RTI-ab negative samples in stage II and the few RTI-ab positive samples among Wb negative sera were sampled in connection with seroconversion. The specificity of the RTI-ab assay was 100% in a test of 200 serum samples from HIV negative blood donors. It was concluded that RTI-ab analyses can be made highly sensitive and specific and useful for studies of HIV infection.
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Affiliation(s)
- M Neumüller
- Research Unit of Replication Enzymology, Uppsala, Sweden
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