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J J Li

Publications and source records attributed to J J Li.

At least 73 records · Page 4Linked to original sources
PubMed1998

Characteristics of vitamin D3 receptor (VDR) binding to the vitamin D response element (VDRE) in rat bone sialoprotein gene promoter.

Bone sialoprotein (BSP) is a mineralised tissue-specific protein that is highly expressed during the initial formation of bone and cementum. Expression of BSP is suppressed by the osteotropic hormone, 1,25-dihydroxyvitamin D3 (vitamin D3), which regulates bone remodelling. In previous studies, we have identified a vitamin D response element (VDRE) that is integrated with a novel inverted TATA box in the rat BSP promoter which mediates the suppression of BSP transcription (1). Although the nucleotide sequences of VDREs in different genes conform to a direct (hexamer) repeat, spaced by three nucleotides, the precise sequences are unique for each VDRE. To determine whether the nucleotide differences in the VDRE influence VDR binding, we have compared interactions of VDR proteins with various VDREs using gel mobility shift analysis. Both natural and recombinant VDRs bound to rat BSP and both mouse and porcine osteopontin (OPN) VDRE oligonucleotides in a concentration-dependent manner with a strong preference for dimer formation, whereas equal amounts of dimer and monomer were bound to the human osteocalcin VDRE. However, whereas a truncated VDR comprising the DNA binding domain alone bound the mouse osteopontin VDRE, it failed to interact with the porcine OPN and rat BSP VDREs. VDR binding to the BSP was sequence specific, as shown by mutagenesis analysis, and could be abolished by heat and VDR antibody. These studies demonstrate that subtle differences in the nucleotide sequence of VDREs affect VDR binding, which mediates the vitamin D3 response.

Animals↗
PubMed1998

Analysis of minimal human immunodeficiency virus type 1 gag coding sequences capable of virus-like particle assembly and release.

We have constructed a series of human immunodeficiency virus (HIV) gag mutants by progressive truncation of the gag coding sequence from the C terminus and have combined these mutants with an assembly-competent matrix domain deletion mutation (DeltaMA). By using several methods, the particle-producing capabilities of each mutant were examined. Our analysis indicated that truncated Gag precursors lacking most of C-terminal gag gene products assembled and were released from 293T cells. Additionally, a mutant with a combined deletion of the MA (DeltaMA) and p6 domains even produced particles at levels comparable to that of the wild-type (wt) virus. However, most mutants derived from combination of the DeltaMA and the C-terminal truncation mutations did not release particles as well as the wt. Our smallest HIV gag gene product capable of virus-like particle formation was a 28-kDa protein which consists of a few MA amino acids and the CA-p2 domain. Sucrose density gradient fractionation analysis indicated that most mutants exhibited a wt retrovirus particle density. Exceptions to this rule were mutants with an intact MA domain but deleted downstream of the p2 domains. These C-terminal truncation mutants possessed particle densities of 1.13 to 1.15 g/ml, lower than that of the wt. The N-terminal portions of the CA domain, which have been shown to be dispensable for core assembly, became critical when most of the MA domain was deleted, suggesting a requirement for an intact CA domain to assemble and release particles.

Amino Acid Sequence↗
PubMed1998

Receptors for advanced glycosylation endproducts in human brain: role in brain homeostasis.

BACKGROUND: Advanced glycation end products (AGEs) are the reactive derivatives of nonenzymatic glucose-macromolecule condensation products. Aging human tissues accumulate AGEs in an age-dependent manner and contribute to age-related functional changes in vital organs. We have shown previously that AGE scavenger receptors are present on monocyte/macrophages, lymphocytes, and other cells. However, it remains unclear whether the human brain can efficiently eliminate AGE-modified proteins and whether excessive AGEs can contribute to inflammatory changes leading to brain injury in aging. MATERIALS AND METHODS: To explore the expression and characteristics of AGE-binding proteins on CNS glia components and their putative function, such as degradation of AGE-modified proteins, primary human astrocytes and human monocytes (as a microglial cell surrogate) and murine microglia (N9) cells and cell membrane extracts were used. Immunohistochemistry was used to examine the distribution of AGE-binding proteins in the human hippocampus; RT-PCR techniques were used to examine the biologic effects of AGEs and a model AGE compound, FFI, on AGE-binding protein modulation and cytokine responses of human astrocytes and monocytes. RESULTS: Our results showed that AGE-binding proteins AGE-R1, -R2, and -R3 are present in glial cells. Western blot analyses and radiolabeled ligand binding studies show that AGE-R1 and -R3 from human astrocytes bind AGE-modified proteins; binding could be blocked by anti-AGE-R1 and anti-AGE-R3 antibodies, respectively. Immunohistochemistry showed that AGE-R1 and -R2 are expressed mainly in neurons; only some glial cells express these AGE-binding proteins. In contrast, AGE-R3 was found only on those astrocytes whose positively stained foot processes extend and surround the sheath of microcapillaries. RT-PCR results showed that mRNAs of the three AGE-binding proteins are expressed constitutively in human astrocytes and monocytes, and receptor transcripts are not regulated by exogenous AGEs, the model AGE compound FFI, or phorbol ester. At the concentrations used, GM-CSF appears to be the only cytokine whose transcript and protein levels are regulated in human astrocytes by exogenous AGEs. CONCLUSIONS: The selective presence of AGE-binding proteins in pyramidal neurons and glial cells and their roles in degrading AGE-modified protein in glial cells suggest that the human brain has a mechanism(s) to clear AGE-modified proteins. Without this capacity, accumulation of AGEs extracellularly could stimulate glial cells to produce the major inflammatory cytokine GM-CSF, which has been shown to be capable of up-regulating AGE-R3. It remains to be determined whether AGE-binding proteins could be aberrant or down-regulated under certain pathological conditions, resulting in an insidious inflammatory state of the CNS in some aging humans.

Aging↗
PubMed1997

CDC45 is required in conjunction with CDC7/DBF4 to trigger the initiation of DNA replication.

The initiation of DNA replication in Saccharomyces cerevisiae requires the protein product of the CDC45 gene. We report that although Cdc45p is present at essentially constant levels throughout the cell cycle, it completes its initiation function in late G1, after START and prior to DNA synthesis. Shortly after mitosis, cells prepare for initiation by assembling prereplicative complexes at their replication origins. These complexes are then triggered at the onset of S phase to commence DNA replication. Cells defective for CDC45 are incapable of activating the complexes to initiate DNA replication. In addition, Cdc45p and Cdc7p/Dbf4p, a kinase implicated in the G1/S phase transition, are dependent on one another for function. These data indicate that CDC45 functions in late G1 phase in concert with CDC7/DBF4 to trigger initiation at replication origins after the assembly of the prereplicative complexes.

Carrier Proteins↗
PubMed1997

Inhibitors of both nuclear factor-kappaB and activator protein-1 activation block the neoplastic transformation response.

Cross-coupling of active protein-1 (AP-1) and nuclear factor (NF)-kappaB has been reported. In the present study, we investigated the possibility that both of these two transcription factors might contribute to the process of tumor promoter-induced transformation. To establish a stable reporter cell system, two reporter genes were stably transfected into a JB6 mouse tumor promotion-sensitive (P+) cell line: a luciferase reporter controlled by a collagenase AP-1 sequence and a chloramphenicol acetyltransferase reporter controlled by an interleukin 6 NF-kappaB sequence. This double-reporter cell line maintained the phenotype of tumor promotion sensitivity and was able to report basal or induced AP-1 and NF-kappaB transactivation. The cytokine tumor promoter tumor necrosis factor (TNF)-alpha transactivated NF-kappaB and AP-1 for both DNA binding and transcriptional activity. Pyrrolidine dithiocarbamate, an antioxidant that acts as an NF-kappaB inhibitor, efficiently inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA) or TNF-alpha induced NF-kappaB as well as AP-1 transactivation and cell transformation, suggesting dependency of transformation on both transcription factors. The AP-1 transrepressing-retinoid SR11302 transrepressed AP-1 and cell transformation when these were TPA induced but not when TNF-alpha induced, indicating different signaling pathways for TNF-alpha and TPA. Supershift electrophoresis mobility shift assay revealed that Jun B and c-Jun were absent from the AP-1/DNA complex following TNF-alpha but present following TPA treatment. Together, these results suggest that both AP-1 and NF-kappaB activation may be required for transformation whether induced by TPA or by TNF, and the differential sensitivity of TPA and TNF-alpha-induced transformation to inhibition by a retinoid might be explained by differences in the composition of the DNA-bound AP-1 complexes.

Animals↗
PubMed1997

Overexpression of manganese-containing superoxide dismutase confers resistance to the cytotoxicity of tumor necrosis factor alpha and/or hyperthermia.

Human breast cancer cells (MCF-7) overexpressing manganese-containing superoxide dismutase (MnSOD) by stable or transient transfection were challenged with the cytotoxicity of tumor necrosis factor alpha (TNF-alpha), hyperthermia, and a combination of both. In contrast to the vector control and wild-type MCF-7 cells, the stable MnSOD transfectants showed significant resistance to the cytotoxicity of TNF-alpha (100 units/ml), heat at 43 or 45 degrees C, and a combination of TNF-alpha and heat at 43 degrees C. To probe the correlation of MnSOD levels with cell survival, cell sensitivity to TNF-alpha, heat at 43 degrees C, or a combination of both was also measured after MnSOD cDNA transient transfection. The data showed that the level of cell resistance was proportional to the exogenous MnSOD gene expression. These results suggest that superoxide free radicals or their reaction products are responsible for much of the synergistic cytotoxicity of TNF-alpha and hyperthermia.

Breast Neoplasms↗
PubMed1997

Glutathione S-transferase Yc cDNA from Syrian hamster kidney.

A cDNA encoding alpha-class glutathione S-transferase Yc (GSTYc) has been isolated from a Syrian hamster kidney library, and its nucleotide sequence (968 bp) has been determined. Analysis of the deduced amino acid sequence revealed a high level of identity between Syrian hamster GSTYc, rat GST Yc1 and Yc2 and mouse GSTYc. Northern-blot experiments demonstrated that Syrian hamster GSTYc expression is tissue-specific. A GSTYc mRNA of approx. 1 kb is expressed in liver, kidney, vas deferens and epididymis. Expression of the GSTYc transcript was not detected in testis or uterus.

Amino Acid Sequence↗
PubMed1997

Induction of cathepsin D protein during estrogen carcinogenesis: possible role in estrogen-mediated kidney tubular cell damage.

We have proposed that an early step in estrogen carcinogenesis in the hamster kidney is tubular damage followed by reparative cell proliferation. This tubular injury is progressive and increases in severity with continued estrogen treatment; one pertinent feature is a marked rise in the number of both secondary and tertiary lysosomes. Data presented herein indicate that cathepsin D, an estrogen-responsive lysosomal proteolytic enzyme, is increased in the kidney following estrogen treatment in the hamster. Three isoforms of cathepsin D were detected in estrogen-treated kidneys, 52, 31, and 27 kDa, the major being 52 kDa. At 1 and 3 months of estrogen treatment, 52-kDa cathepsin D content increased 1.4- to 1.6-fold. These changes coincided with a rise in renal estrogen receptor levels during the same estrogen treatment periods. More pronounced rises in cathepsin D levels, 2.7- and 3.5-fold, were seen after 4 and 5 months of estrogen treatment, respectively. A concomitant, 3.0- to 4.0-fold rise in estrogen receptor content was also observed. At 5 months of estradiol or DES treatment, both 27- and 31-kDa isoforms were present in hamster kidneys, in addition to the 52-kDa form. Neither progesterone nor DHT treatment affected the untreated levels of cathepsin D. Interestingly, either concomitant tamoxifen or DHT and estrogen treatment prevented the rise in cathepsin D and estrogen receptor content observed after estrogen treatment alone. Primary estrogen-induced renal tumors and their metastases exhibited markedly elevated levels of all three isoforms of cathepsin D. Immunohistochemical analysis of cathepsin D in kidney sections confirmed the Western blot findings. These data suggest a novel role for estrogen-induced cathepsin D in the hamster kidney during tumorigenesis; that is, mediating renal tubular damage as a prelude to reparative cell proliferation, thus initiating a multi-step estrogen-driven process which leads to renal tumor formation.

Animals↗
PubMed1997

Ethanol down-regulates the transcription of microsomal triglyceride transfer protein gene.

Microsomal triglyceride transfer protein (MTP) plays a central role in the assembly and secretion of apoB-containing lipoproteins. In this study, we investigated the effect of ethanol on the expression of the large subunit of MTP in a human liver hepatoma cell line, the HepG2 cells. Exposure of HepG2 cells to low concentrations of ethanol reduced MTP mRNA levels in a concentration- and time-dependent manner. The level of MTP mRNA decreased significantly (P<0.05, -26% relative to pretreatment control) when the concentration of ethanol in the culture medium was 50 ppm (0.005%, v/v). Maximal suppression (-50%) was observed at 100 ppm ethanol; the MTP mRNA levels remained at 50% of control when the ethanol concentration was raised to 10,000 ppm. Furthermore, a 10-day ethanol treatment caused a significant 50% decrease in the MTP activity and apoB secretion rate in HepG2 cells. To investigate the molecular mechanisms underlying this phenomenon, we examined the effect of ethanol on the promoter activity of the MTP gene. Transient transfection analysis of human MTP promoter-driven luciferase gene expression showed that ethanol down-regulates MTP promoter activity in a manner parallel to that observed for mRNA levels. Deletion analysis suggested that the MTP promoter sequence contains a negative ethanol response element -612 to -142 bp upstream of the transcription start site. To evaluate the in vivo relevance of the effect of ethanol on MTP mRNA levels, rats were given a single oral dose of ethanol, with hepatic and intestinal MTP mRNA measured 3 h after dosing. Rats receiving 1 or 3 g/kg of ethanol exhibited substantially lower hepatic and intestinal MTP mRNA levels. Taken together, these results strongly suggest that ethanol can modulate the secretion of apoB-containing lipoproteins by down-regulating the expression of MTP large subunit, primarily through inhibiting the transcription of the MTP gene.

Animals↗
PubMed1997

Expression and mutation of the tumor suppressor gene p53 in AIDS-associated Kaposi's sarcoma.

Alteration of the p53 gene is the most frequent event reported in human cancer, and p53 mutations have been observed in various neoplasms, including certain forms of skin cancer. Therefore, we postulated that p53 may also be involved in Kaposi's sarcoma associated with AIDS (AIDS-KS). Expression of the p53 gene was examined in freshly isolated tumor biopsy specimens from 15 patients with AIDS-KS. p53 mRNA was detected by reverse transcriptase-polymerase chain reaction (RT-PCR) in both the AIDS-KS tumors and in normal skin control samples. p53 protein was detected in 4 of the 15 AIDS-KS specimens by immunohistochemical staining. Single-strand conformation polymorphism analysis PCR-products (PCR-SSCP) was used for detection of mutations of the p53 gene. One of the p53 positive AIDS-KS samples showed mobilized shifts in exon 6 suggestive of a mutation. Sequencing data showed the mutation to be located in codon 210. We examined other mechanisms that could stabilize p53 protein. SV40 large T antigen and adenovirus E1B protein were not found in the AIDS-KS specimens. MDM2, a p53-binding protein, was also detected in five of the AIDS-KS specimens, two of which also contained p53-positive cells. These observations suggest that the tumor suppressor gene p53 may be involved in the pathogenesis of AIDS-KS.

AIDS-Related Opportunistic Infections↗
PubMed1997

Human herpesvirus 8 encodes a homolog of interleukin-6.

Kaposi's sarcoma is a multifocal lesion that is reported to be greatly influenced by cytokines such as interleukin-6 (IL-6) and oncostatin M. DNA sequences of a novel human gammaherpesvirus, termed human herpesvirus 8 (HHV-8) or Kaposi sarcoma-associated herpesvirus, have been identified in all epidemiological forms of Kaposi's sarcoma with high frequency. The presence of HHV-8 DNA is also clearly associated with certain B-cell lymphomas (body cavity-based lymphomas) and multicentric Castleman's disease. Sequence analysis of a 17-kb fragment revealed that adjacent to a block of conserved herpesvirus genes (major DNA-binding protein, glycoprotein B, and DNA polymerase), the genome of HHV-8 encodes structural homolog of IL-6. This cytokine is involved not only in the pathogenesis of Kaposi's sarcoma but also in certain B-cell lymphomas and multicentric Castleman's disease. The viral counterpart of IL-6 (vIL-6) has conserved important features such as cysteine residues involved in disulfide bridging or an amino-terminal signal peptide. Most notably, the region known to be involved in receptor binding is highly conserved in vIL-6. This conservation of essential features and the remarkable overlap between diseases associated with HHV-8 and diseases associated with IL-6 disregulation clearly suggest that vIL-6 is involved in HHV-8 pathogenesis.

Amino Acid Sequence↗
PubMed1997

Adenovirus-mediated expression of the secreted form of basic fibroblast growth factor (FGF-2) induces cellular proliferation and angiogenesis in vivo.

Blood supply through collateral arteries is of critical importance in occlusive arterial diseases such as coronary atherosclerosis. Induction of angiogenic growth factor within either the narrowing arteries or jeopardized myocardium may promote angiogenesis in vivo, leading to salvage of ischemic myocardium. We constructed a replication-defective adenovirus (AdCAsFGF-2) coding for human basic fibroblast growth factor (FGF)-2 that is modified, so that its secretion will be facilitated, by tagging a signal sequence derived from FGF-4. A large quantity of FGF-2 was detected in both the cell lysate and culture medium of COS cells infected with AdCAsFGF-2, indicating that FGF-2 was secreted at least partly from the infected cells. The conditioned medium from the infected COS cells stimulated DNA synthesis in and induced cellular proliferation of arterial smooth muscle cells. These effects were eliminated by adenovirus-mediated overexpression of a dominant-negative truncated FGF-receptor type 1. Implantation of a gel of basement membrane proteins containing fibroblasts infected with AdCAsFGF-2 into the ventral subcutaneous space of mice induced extensive cellular proliferation and the formation of functional arterioles. Cells surrounding the vessels were positively immunostained with antibodies recognizing either smooth muscle-specific alpha-actin or factor VIII antigen as a marker for endothelium. These results suggest that AdCAsFGF-2 may be useful for delivering functional FGF-2 into tissues and may lead to therapeutic angiogenesis in vivo.

Actins↗
PubMed1997

Adenovirus-mediated transfer of a dominant-negative H-ras suppresses neointimal formation in balloon-injured arteries in vivo.

Abnormal migration and proliferation of arterial smooth muscle cells may be a central event in inflammatory proliferative arterial diseases such as atherosclerosis and restenosis after angioplasty. The proto-oncogene c-H-ras is considered to be a key transducer in various growth-signaling events. We constructed an adenoviral vector (AdexCAHRasY57) expressing a potent dominant-negative mutated form of c-H-ras in which tyrosine replaces aspartic acid at residue 57. Infection of smooth muscle cells with AdexCAHRasY57 produced a large quantity of H-ras-p21, completely inhibited serum-stimulated activation of mitogen-activated protein kinase, and abolished the DNA synthesis in response to serum mitogens. However, a surge of intracellular Ca2+ concentration in response to platelet-derived growth factor was not affected, suggesting that some cellular functions were preserved. When we applied AdexCAHRasY57 into balloon-injured rat carotid arteries from inside the lumen, neointimal formation was significantly reduced (neointima/media ratio: 0.28) compared with that (1.50) in arteries treated with either injury alone or injury and infection with a control adenovirus, AdexCALacZ, expressing bacterial beta-galactosidase. Our results suggest that adenovirus-mediated arterial transfer of dominant-negative H-ras may be a practical form of effective molecular intervention for proliferative arterial diseases.

Adenoviridae↗
PubMed1997

Cdc6p establishes and maintains a state of replication competence during G1 phase.

CDC6 is essential for the initiation of DNA replication in the budding yeast Saccharomyces cerevisiae. Here we examine the timing of Cdc6p expression and function during the cell cycle. Cdc6p is expressed primarily between mitosis and Start. This pattern of expression is due in part to posttranscriptional controls, since it is maintained when CDC6 is driven by a constitutively induced promoter. Transcriptional repression of CDC6 or exposure of cdc6-1(ts) cells to the restrictive temperature at mitosis blocks subsequent S phase, demonstrating that the activity of newly synthesized Cdc6p is required each cell cycle for DNA replication. In contrast, similar perturbations imposed on cells arrested in G(1) before Start have moderate or no effects on DNA replication. This suggests that, between mitosis and Start, Cdc6p functions in an early step of initiation, effectively making cells competent for replication. Prolonged exposure of cdc6-1(ts) cells to the restrictive temperature at the pre-Start arrest eventually does cripple S phase, indicating that Cdc6p also functions to maintain this initiation competence during G(1). The requirement for Cdc6p to establish and maintain initiation competence tightly correlates with the requirement for Cdc6p to establish and maintain the pre-replicative complex at a replication origin, strongly suggesting that the pre-replicative complex is an important intermediate for the initiation of DNA replication. Confining assembly of the complex to G(1) by restricting expression of Cdc6p to this period may be one way of ensuring precisely one round of replication per cell cycle.

Cell Cycle Proteins↗
PubMed1997

Detection of the herpesvirus-like DNA sequences in matched specimens of semen and blood from patients with AIDS-related Kaposi's sarcoma by polymerase chain reaction in situ hybridization.

The DNA sequences of a novel human gamma-herpesvirus type 8 (HHV-8) have recently been detected in Kaposi's sarcoma (KS) lesions obtained from different populations in whom this neoplasm occurs, suggesting that this virus may be implicated in the etiology and/or pathogenesis of KS. To study the distribution and possible means of transmission of the putative viral agent, specimens of KS skin lesions, matched uninvolved skin, peripheral blood mononuclear cells (PB-MCs), and semen were collected from 12 HIV-positive homosexual men with acquired immune deficiency syndrome (AIDS)-related KS (AIDS-KS) and 2 human immunodeficiency virus (HIV)-negative homosexual men with KS. HHV-8 virus DNA was detected by polymerase chain reaction (PCR) studies in all 14 of these KS specimens and in 6 of 14 biopsies of normal-appearing skin distant from any KS lesions including 1 uninvolved skin specimen from an HIV-negative homosexual male with KS. In addition, 3 of 12 PBMC samples and 3 of 12 semen samples from the AIDS-KS patients were positive for HHV-8. The DNA sequences of HHV-8 were not detected in the matched semen and PBMC specimens obtained from 2 HIV-negative homosexual men with KS, 4 HIV-positive homosexual patients without KS, 2 HIV-seronegative healthy homosexual men, 5 HIV-positive heterosexual male intravenous drug users, or 5 healthy HIV-negative heterosexual donors. Using PCR in situ, positive signals for HHV-8 were demonstrated in the B lymphocyte subsets of PBMCs and/or in spermatozoa and mononuclear cells in the semen from some of the PCR-positive specimens from the AIDS-KS patients examined. These data show that HHV-8 is present in and could possibly be transmitted via semen and/or blood from some homosexual men with AIDS-KS.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Identification of a vitamin D3-response element that overlaps a unique inverted TATA box in the rat bone sialoprotein gene.

Bone sialoprotein (BSP), an early marker of osteoblast differentiation, has been implicated in the nucleation of hydroxyapatite during bone formation de novo. Our studies, using the osteoblastic cell line ROS 17/2.8, have revealed that rat BSP gene expression is suppressed by 1,25-dihydroxyvitamin D3[1,25(OH)2D3], which is a powerful regulator of bone formation and resorption. To determine the molecular basis of the transcriptional suppression of BSP gene transcription by 1,25(OH)2D3, we have conducted transient transfection analyses with chimaeric constructs of the rat BSP gene promoter linked to a luciferase reporter gene. 1,25(OH)2D3 suppressed expression in all constructs, including a short construct (pLUC 3; nt -116 to +60) that contained a putative vitamin D3-response element (VDRE; AGGGTTTATAGGTCA; nt -28 to -14) that overlaps a unique inverted TATA (TTTATA) box. Mobility shift assays demonstrated strong binding of recombinant human vitamin D3 receptor protein (hVDR) to the VDRE. Point mutations introduced into each half-site and analysed for 1,25(OH)2D3-mediated suppression of transcription and for hVDR binding either decreased or increased both transcriptional suppression and binding. In comparison with activating VDREs, the rat BSP VDRE bound VDR-VDR homodimers more avidly than VDR-RXR alpha heterodimers (where RXR is retinoid X receptor). These studies have therefore identified a novel 1,25(OH)2D3 suppressor element that overlaps the inverted TATA box in the rat BSP gene and indicate that transcriptional suppression of the rat BSP gene by 1,25(OH)2D3 might involve competition between the VDR and the TATA binding protein (TBP).

Animals↗
PubMed1996

Transcription of human herpesvirus-like agent (HHV-8) in Kaposi's sarcoma.

Recently, DNA sequences of what appear to be a unique human herpesvirus-like agent (HHV-8) have been detected in different types of Kaposi's sarcoma (KS) tumors (Chang, Y., E.C. Cesarman, M.S. Pessin, F. Lee, J.C. Culpepper, D.M. Knowles, and P.S. Moore. 1994. Science (Wash. DC). 266:1865-1869). To further elucidate the possibility that HHV-8 plays a role in the pathogenesis of KS, the expression of HHV-8 RNA was examined in fresh KS tissue specimens which were found to harbor HHV-8 DNA by polymerase chain reaction (PCR). The transcription of HHV-8 RNA was detected by RT-PCR in 26 of 29 specimens (89.7%) of the KS tumors including 2 of 3 CKS and 24 of 26 AIDS-KS. No positive signal was detected in eight biopsy specimens of normal skin from healthy donors. By Northern blot analysis, the expression of HHV-8 was detected in 2 of 10 KS tumors examined. Furthermore, the RNA transcripts were observed in endothelial cells lining the irregular vascular spaces and perivascular spindle-shaped cells histologically characteristic of KS in 2 out of 8 different KS specimens examined by in situ hybridization using an antisense probe specific of HHV-8. The detection of RNA expression of HHV-8 in KS tumors further supports the possible etiopathogenic role of this virus in the development of KS.

Base Sequence↗