Nubian Levallois technology associated with southernmost Neanderthals

Neanderthals occurred widely across north Eurasian landscapes, but between ~ 70 and 50 thousand years ago (ka) they expanded southwards into the Levant, which had previously been inhabited by Homo sapiens. Palaeoanthropological research in the first half of the twentieth century demonstrated alternate occupations of the Levant by Neanderthal and Homo sapiens populations, yet key early findings have largely been overlooked in later studies. Here, we present the results of new examinations of both the fossil and archaeological collections from Shukbah Cave, located in the Palestinian West Bank, presenting new quantitative analyses of a hominin lower first molar and associated stone tool assemblage. The hominin tooth shows clear Neanderthal affinities, making it the southernmost known fossil specimen of this population/species. The associated Middle Palaeolithic stone tool assemblage is dominated by Levallois reduction methods, including the presence of Nubian Levallois points and cores. This is the first direct association between Neanderthals and Nubian Levallois technology, demonstrating that this stone tool technology should not be considered an exclusive marker of Homo sapiens.

The morphology of the Late Pleistocene hominin remains from the site of La Cotte de St Brelade, Jersey (Channel Islands)

Thirteen permanent fully erupted teeth were excavated at the Paleolithic site of La Cotte de St Brelade in Jersey in 1910 and 1911. These were all found in the same location, on a ledge behind a hearth in a Mousterian occupation level. They were originally identified as being Neanderthal. A fragment of occipital bone was found in a separate locality in a later season. Recent dating of adjacent sediments gives a probable age of <48 ka. The purpose of this article is to provide an updated description of the morphology of this material and consider its likely taxonomic assignment from comparison with Neanderthal and Homo sapiens samples. One of the original teeth has been lost, and we identify one as nonhominin. At least two adult individuals are represented. Cervix shape and the absence of common Neanderthal traits in several teeth suggest affinities with H. sapiens in both individuals, while crown and root dimensions and root morphology of all the teeth are entirely consistent with a Neanderthal attribution, pointing toward a possible shared Neanderthal and H. sapiens ancestry (the likely date of this material corresponds with the time in which both Neanderthals and H. sapiens were present in Europe). The occipital fragment is stratigraphically more recent and does not exhibit any diagnostic Neanderthal features.

Middle Stone Age human teeth from Magubike rockshelter, Iringa Region, Tanzania

In 2006, six isolated hominin teeth were excavated from Middle Stone Age (MSA) deposits at the Magubike rockshelter in southern Tanzania. They comprise two central incisors, one lateral incisor, one canine, one third premolar, and one fourth premolar. All are fully developed and come from the maxilla. None of the teeth are duplicated, so they may represent a single individual. While there is some evidence of post-depositional alteration, the morphology of these teeth clearly shares features with anatomically modern Homo sapiens. Both metric and non-metric traits are compared to those from other African and non-African dental remains. The degree of biological relatedness between eastern and southern African Stone Age hunter-gatherers has long been a subject of interest, and several characteristics of the Magubike teeth resemble those of the San of southern Africa. Another notable feature is that the three incisors are marked on the labial crown by scratches that are much coarser than microwear striations. These non-masticatory scratches on the Magubike teeth suggest that the use of the front teeth as tools included regularly repeated activities undertaken throughout the life of the individual. The exact age of these teeth is not clear as ESR and radiocarbon dates on associated snail shells give varying results, but a conservative estimate of their minimum age is 45,000 years.

Interactive Retro-Deformation of Terrain for Reconstructing 3D Fault Displacements

Planetary topography is the result of complex interactions between geological processes, of which faulting is a prominent component. Surface-rupturing earthquakes cut and move landforms which develop across active faults, producing characteristic surface displacements across the fault. Geometric models of faults and their associated surface displacements are commonly applied to reconstruct these offsets to enable interpretation of the observed topography. However, current 2D techniques are limited in their capability to convey both the three-dimensional kinematics of faulting and the incremental sequence of events required by a given reconstruction. Here we present a real-time system for interactive retro-deformation of faulted topography to enable reconstruction of fault displacement within a high-resolution (sub 1m/pixel) 3D terrain visualization. We employ geometry shaders on the GPU to intersect the surface mesh with fault-segments interactively specified by the user and transform the resulting surface blocks in realtime according to a kinematic model of fault motion. Our method facilitates a human-in-the-loop approach to reconstruction of fault displacements by providing instant visual feedback while exploring the parameter space. Thus, scientists can evaluate the validity of traditional point-to-point reconstructions by visually examining a smooth interpolation of the displacement in 3D. We show the efficacy of our approach by using it to reconstruct segments of the San Andreas fault, California as well as a graben structure in the Noctis Labyrinthus region on Mars.

Down-regulation of epidermal growth factor receptor-dependent signaling by Porphyromonas gingivalis lipopolysaccharide in life-expanded human gingival fibroblasts

BACKGROUND AND OBJECTIVE

Human gingival fibroblasts exhibit proliferative responses following epidermal growth factor exposure, which are thought to enhance periodontal regeneration in the absence of bacterial products such as lipopolysacharide. However, lipopolysaccharide challenge activates human gingival fibroblasts to release several inflammatory mediators that contribute to the immune response associated with periodontitis and attenuate wound repair. We tested the hypothesis that Porphyromonas gingivalis lipopolysaccharide-activated signaling pathways down-regulate epidermal growth factor receptor-dependent events.

MATERIAL AND METHODS

To study lipopolysaccharide/epidermal growth factor interactions in human gingival fibroblasts, we introduced the catalytic subunit of human telomerase into human gingival fibroblasts, thereby generating a more long-lived cellular model. These cells were characterized and evaluated for lipopolysaccharide/epidermal growth factor responsiveness and regulation of epidermal growth factor-dependent pathways.

RESULTS

Comparison of human telomerase-transduced gingival fibroblasts with human gingival fibroblasts revealed that both cell lines exhibit a spindle-like morphology and express similar levels of epidermal growth factor receptor, CD14 and Toll-like receptors 2 and 4. Importantly, human telomerase-transduced gingival fibroblasts proliferation rates are increased 5-9 fold over human gingival fibroblasts and exhibit a longer life span in culture. In addition, human telomerase-transduced gingival fibroblasts and human gingival fibroblasts exhibit comparable profiles of mitogen-activated protein kinase kinase (extracellular signal-regulated kinase 1/2) activation upon epidermal growth factor or P. gingivalis lipopolysaccharide administration. Interestingly, treatment with P. gingivalis lipopolysaccharide leads to a down-regulation of epidermal growth factor-dependent extracellular signal-regulated kinase 1/2, p38 and cyclic-AMP response element binding protein phosphorylation in both cell types.

CONCLUSION

These studies demonstrate that human telomerase-transduced gingival fibroblasts exhibit an extended life span and recapitulate human gingival fibroblasts biology. Moreover, this system has allowed for the first demonstration of lipopolysaccharide down-regulation of epidermal growth factor activated pathways in human gingival fibroblasts and should facilitate the analysis of signaling events relevant to the pathogenesis and treatment of periodontitis.

Critical role of lysophospholipids in the pathophysiology, diagnosis, and management of ovarian cancer

Lysophosphatidic acid (LPA), the simplest of all phospholipids, exhibits pleiomorphic functions in multiple cell lineages. The effects of LPA appear to be mediated by binding of LPA to specific members of the endothelial differentiation gene (Edg) family of G protein-coupled receptors (GPCR). Edg 2, Edg4, and Edg7 are high affinity receptors for LPA, and Edg1 may be a low affinity receptor for LPA. PSP24 has been shown to be responsive to LPA in Xenopus oocytes, however, its role in mammalian cells is unclear. The specific biochemical events initiated by the different Edg receptors, as well as the biological outcomes of activation of the individual receptors, are only beginning to be determined. LPA levels are consistently elevated in the plasma and ascites of ovarian cancer patients, but not in most other epithelial tumors, with the exception of cervix and endometrium, suggesting that LPA may be of particular importance in the pathophysiology of ovarian cancer. In support of this concept, ovarian cancer cells constitutively and inducibly produce high levels of LPA and demonstrate markedly different responses to LPA than normal ovarian surface epithelium. Edg4 and Edg7 levels are consistently increased in malignant ovarian epithelial cells contributing to the aberrant response of ovarian cancer cells to LPA. Edg2 may represent a negative regulatory LPA receptor inducing apoptosis in ovarian cancer cells. Thus, increased levels of LPA, altered receptor expression and altered responses to LPA may contribute to the initiation, progression or outcome of ovarian cancer. Over 40% of known drugs target GPCR, making LPA receptors attractive targets for molecular therapeutics. Indeed, using the structure-function relationship of LPA in model systems, we have identified selective Edg2 anatgonists, as well as Edg4 and Edg7 agonists. These lead compounds are being assessed in preclinical model systems. Understanding the mechanisms regulating LPA production, metabolism and function could lead to improved methods for early detection and to new targets for therapy in ovarian cancer.

Characterization of the signal peptide processing and membrane association of human cytomegalovirus glycoprotein O

Human cytomegalovirus (HCMV) has a structurally complex envelope that contains multiple glycoproteins. These glycoproteins are involved in virus entry, virus maturation, and cell-cell spread of infection. Glycoprotein H (gH), glycoprotein L (gL), and glycoprotein O (gO) associate covalently to form a unique disulfide-bonded tripartite complex. Glycoprotein O was recently discovered, and its basic structure, as well as that of the tripartite complex, remains uncharacterized. Based on hydropathy analysis, we hypothesized that gO could adopt a type II transmembrane orientation. The data presented here, however, reveal that the single hydrophobic domain of gO functions as a cleavable signal peptide that is absent from the mature molecule. Although it lacks a membrane anchor, glycoprotein O is associated with the membranes of HCMV-infected cells. The sophisticated organization of the gH.gL.gO complex reflects the intricate nature of the multicomponent entry and fusion machinery encoded by HCMV.

Global modulation of cellular transcription by human cytomegalovirus is initiated by viral glycoprotein B

Human cytomegalovirus (HCMV) infection alters the expression of many cellular genes, including IFN-stimulated genes (ISGs) [Zhu, H., Cong, J.-P., Mamtora, G., Gingeras, T. & Shenk, T. (1998) Proc. Natl. Acad. Sci. USA 95, 14470-14475]. By using high-density cDNA microarrays, we show that the HCMV-regulated gene expression profile in fibroblasts does not differ substantially from the response generated by IFN. Furthermore, we identified the specific viral component triggering this response as the envelope glycoprotein B (gB). Cells treated with gB, but not other herpesviral glycoproteins, exhibited the same transcriptional profile as HCMV-infected cells. Thus, the interaction of gB with its as yet unidentified cellular receptor is the principal mechanism by which HCMV alters cellular gene expression early during infection. These findings highlight a pioneering paradigm for the consequences of virus-receptor interactions.

Web-based multimedia courseware for emergency cardiac patient management simulations

This is a multidisciplinary inter-departmental/faculty project between the departments of computer science, electronic, communications and electrical engineering and nursing and paramedic sciences. The objective is to develop a web based multimedia front end to existing simulations of cardiac emergency scenaria. It will be used firstly in the teaching of nurses. The University of Hertfordshire is the only University in Britain using simulations of cardiac emergency scenaria for nurse and paramedic science education and therefore this project will add the multimedia dimension in distributed courses over the web and will assess the improvement in the educational process. The use of network and multimedia technologies, provide interactive learning, immediate feedback to students' responses, individually tailored instructions, objective testing and entertaining delivery. The end product of this project will serve as interactive material to enhance experiential learning for nursing students using the simulations of cardiac emergency scenaria. The emergency treatment simulations have been developed using VisSim and may be compiled as C code. The objective of the project is to provide a web based user friendly multimedia interface in order to demonstrate the way in which patients may be managed in critical situations by applying advanced technological equipment and drug administration. Then the user will be able to better appreciate the concepts involved by running the VisSim simulations. The evaluation group for the proposed software will be the Department of Nursing and Paramedic Sciences About 200 nurses use simulations every year for training purposes as part of their course requirements.

Predictors of glycemic control in children with type 1 diabetes: the importance of race

Diabetes is a common cause of kidney failure and blindness among young adults, particularly of African-American descent. Since glycemic control is a predictor of diabetes complications, we evaluated the impact of multiple factors including a special multidisciplinary management program on glycosylated hemoglobin in children with Type 1 diabetes. Data was collected from pediatric diabetes clinics in New Orleans, LA and Baltimore, MD. In New Orleans, hemoglobin A(1c) was higher in African-American patients 12. 5+/-3.3% (n=71) vs. 10.7+/-2.1% (n=80) in Caucasian children, p<0. 0001. Longer duration of diabetes was also associated with higher hemoglobin A(1c) in both races. The effect of race on hemoglobin A(1c) was independent of the influence of sex, insurance status, body mass index (BMI) z-score, and number of clinic visits. Covariate analysis with mean blood glucose levels indicated that higher hemoglobin A(1c) was attributable to higher mean blood glucose levels in African-American children. From the Baltimore data, a multidisciplinary intervention program led to improved total glycosylated hemoglobin for Caucasian patients but not for African-American children. Poorer glycemic control of African-American children is likely to predispose them to a higher likelihood of developing microvascular complications as they mature. Standard hospital-based multidisciplinary programming for diabetes management may have limited effectiveness in improving glycemic control of African-American children with diabetes. Innovative intervention programs are needed for these high-risk patients.

Characterization of a panel of insertion mutants in human cytomegalovirus glycoprotein B

Glycoprotein B (gB; gpUL55) of human cytomegalovirus (HCMV) plays a critical role in virus entry and cell-to-cell spread of infection. To define the structure-function relationships in gB, a panel of linker-insertion mutations was generated throughout the coding region. This strategy yielded a panel of 22 mutants with four amino acid insertions and 3 large truncation mutants. Assessment of the mutant proteins' biosynthetic properties and folding patterns analyzed in context with predicted secondary features revealed novel insights into gB's structure and trafficking properties. All of the insertion mutants were able to assemble into oligomers, suggesting that oligomerization is tolerant of small insertions and/or that multiple regions of the protein may be involved. Computer algorithm predictions of gB's secondary structure indicate that the furin-recognized cleavage site falls within an exposed loop. This loop may be particularly sensitive to structural alterations, since insertions upstream and downstream of the cleavage site rendered the mutant proteins cleavage defective. In addition, a strong correlation existed between terminal folding and cleavage of gB. Interestingly, terminal folding was not correlated with delivery to the cell surface but may influence the rate of transport to the cell surface. Nine mutants, containing insertions in both the extracellular and intracellular portions of gB, retained wild-type structural properties. This panel of characterized gB mutants, the first of this type for an HCMV protein, will be a useful tool in dissecting the role of gB during HCMV infection.

Interference with annexin II has no effect on entry of human cytomegalovirus into fibroblast cells

Annexin II has been identified as a human cytomegalovirus (HCMV)-binding protein, shown to be a component of purified virions and proposed as a cellular receptor for the virus. In addition, annexin II is capable of associating with the major HCMV envelope glycoprotein, gB (gpUL55). As one approach to examine the role of annexin II in virus entry, a high-titre polyclonal annexin II-specific antibody was produced and its effects in virus entry and cell-to-cell spread assays were tested. This anti-annexin II serum recognized virion and cell surface annexin II and annexin II-derived peptides. Recombinant annexin II, with characteristic calcium- and phospholipid-binding activities, was also examined. Pretreatment of cells, virions or both with polyclonal anti-annexin II serum, affinity-purified anti-annexin II antibodies or recombinant annexin II protein prior to infection was inconsequential to the entry of HCMV into fibroblasts. HCMV was also able to dose-dependently penetrate annexin II-deficient 293 cells. Furthermore, the spread of HCMV from cell to cell was not inhibited in the presence of polyclonal anti-annexin II antibodies or exogenous annexin II protein. These experiments do not support a direct role of annexin II in virus entry or spread. Alternative roles for the gB-annexin II interaction are proposed.

Helicobacter pylori infection and insulin requirement among children with type 1 diabetes mellitus

OBJECTIVE

Helicobacter pylori induces gastric inflammation and the the production of cytokines in infected individuals. Theoretically, this increased production of cytokines could be deleterious for the control of the glycemia of patients with diabetes. This study aimed to describe the insulin requirement among patients with type 1 diabetes and H pylori infection compared with uninfected counterparts.

METHODS

Cross-sectional design. Demographic information (age, gender, race, annual family income, and number of individuals per room in the household) and clinical information (age at diagnosis of diabetes, duration of illness, weight, height, compliance with clinical appointments, daily insulin units per kilogram of body weight [IU/kg/d], and glycosylated hemoglobin A level) was obtained from children and adolescents with diagnosis of type 1 diabetes mellitus who were seen at Children's Hospital in New Orleans. A total of 2 mL of blood was also collected and sera were tested for H pylori-specific immunoglobulin G antibodies using an enzyme immunoassay. The daily insulin requirement among infected and uninfected children was compared, and the effect of other variables was evaluated with multiple linear regression.

RESULTS

Of the 71 subjects who were evaluated (median age: 11 years), 11 (15.5%) were found to be infected. H pylori infection was more frequent among subjects who were older, who had a lower family income, and who were black. Infected children were found to require more insulin (1.2 vs 0.9 IU/Kg/d) and their glycosylated hemoglobin A level was higher (14.9 vs 11.8) than the level found in uninfected subjects. Multiple linear regression analysis identified H pylori infection duration of illness, race (black), body mass index, and gender (female), to be associated independently with increased daily insulin requirement (IU/kg/d).

CONCLUSION

n our study population, children with type 1 diabetes and H pylori infection had an increased daily insulin requirement compared with the requirement of their uninfected peers. The reason for this association requires additional investigation.

Engagement of the cellular receptor for glycoprotein B of human cytomegalovirus activates the interferon-responsive pathway

Cells respond to contact with human cytomegalovirus (HCMV) virions by initiating intracellular signaling and gene expression characteristic of the interferon (IFN)-responsive pathway. Herein, we demonstrate that a principal mechanism of HCMV-induced signal transduction is via an interaction of the primary viral ligand, glycoprotein B (gB), with its cellular receptor. Cells incubated with a purified, soluble form of gB resulted in the transcriptional upregulation of IFN-responsive genes OAS and ISG54 (encoding 2'-5' oligoadenylate synthetase and an IFN-stimulated gene product of 54 kDa) to a comparable level as virions or IFN. Gene induction was an immediate and direct response to gB which did not require de novo protein synthesis. Neither the initial virus attachment site, heparan sulfate proteoglycans, nor the IFN-alpha/beta or IFN-gamma receptors are involved in the response. Pleotropic protein phosphorylation was required for cellular gene induction, and the mitogen-activated protein kinases ERK1 and ERK2 were activated in response to the ligand. Together these data indicate that a principal means by which cytomegalovirus induces intracellular signaling and activation of the interferon-responsive pathway is via an interaction of gB with an as yet unidentified, likely novel cellular receptor that interfaces with the IFN signaling pathway.

Intracellular formation and processing of the heterotrimeric gH-gL-gO (gCIII) glycoprotein envelope complex of human cytomegalovirus

The human cytomegalovirus (HCMV) gCIII complex contains glycoprotein H (gH; gpUL75), glycoprotein L (gL; gpUL115), and glycoprotein O (gO; gpUL74). To examine how gH, gL, and gO interact within HCMV-infected cells to assemble the tripartite complex, pulse-chase experiments were performed. These analyses demonstrated that gH and gL associate by the end of the pulse period to form a disulfide dependent gH-gL complex. Subsequently, the gH-gL complex interacts with a 100-kDa precursor form of gO to form a 220-kDa precursor of the mature gH-gL-gO complex that contains a 125-kDa form of gO. The 220-kDa precursor complex (pgCIII) was sensitive to treatment with endoglycosidase H (endo H), while the mature gCIII complex was essentially resistant to digestion with this enzyme, suggesting that formation of pgCIII complex occurs in the endoplasmic reticulum (ER) and is processed to mature gH-gL-gO (gCIII) in a post-ER compartment. While the N-linked glycans on the 100-kDa form of gO were modified to endo H-resistant states as the 125-kDa gO formed, additional posttranslational modifications were detected on gO. These processing alterations were non-N-linked oligosaccharide modifications that could not be accounted for by phosphorylation or by O-glycosylation of the type sensitive to O-glycanase. Of gH, gL, gO, and the various complexes that they form, only the mature form of the complex was detectable at the infected cell membrane, as judged by surface biotinylation studies.

The human cytomegalovirus UL74 gene encodes the third component of the glycoprotein H-glycoprotein L-containing envelope complex

The human cytomegalovirus (HCMV) gCIII envelope complex is composed of glycoprotein H (gH; gpUL75), glycoprotein L (gL; gpUL115), and a third, 125-kDa protein not related to gH or gL (M. T. Huber and T. Compton, J. Virol. 71:5391-5398, 1997; L. Li, J. A. Nelson, and W. J. Britt, J. Virol. 71:3090-3097, 1997). Glycosidase digestion analysis demonstrated that the 125-kDa protein was a glycoprotein containing ca. 60 kDa of N-linked oligosaccharides on a peptide backbone of 65 kDa or less. Based on these biochemical characteristics, two HCMV open reading frames, UL74 and TRL/IRL12, were identified as candidate genes for the 125-kDa glycoprotein. To identify the gene encoding the 125-kDa glycoprotein, we purified the gCIII complex, separated the components by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and subjected gH and the 125-kDa glycoprotein to amino acid microsequence analysis. Microsequencing of an internal peptide derived from purified 125-kDa glycoprotein yielded the amino acid sequence LYVGPTK. A FASTA search revealed an exact match of this sequence to amino acids 188 to 195 of the predicted product of the candidate gene UL74, which we have designated glycoprotein O (gO). Anti-gO antibodies reacted in immunoblots with a protein species migrating at ca. 100 to 125 kDa in lysates of HCMV-infected cells and with 100- and 125-kDa protein species in purified virions. Anti-gO antibodies also immunoprecipitated the gCIII complex and recognized the 125-kDa glycoprotein component of the gCIII complex. Positional homologs of the UL74 gene were found in other betaherpesviruses, and comparisons of the predicted products of the UL74 homolog genes demonstrated a number of conserved biochemical features.

Receptor-binding properties of a soluble form of human cytomegalovirus glycoprotein B

The human cytomegalovirus (HCMV) glycoprotein B (gB) (also known as gpUL55) homolog is an important mediator of virus entry and cell-to-cell dissemination of infection. To examine the potential ligand-binding properties of gB, a soluble form of gB (gB-S) was radiolabeled, purified, and tested in cell-binding experiments. Binding of gB-S to human fibroblast cells was found to occur in a dose-dependent, saturable, and specific manner. Scatchard analysis demonstrated a biphasic plot with the following estimated dissociation constants (Kd): Kd1, 4.96 x 10(-6) M; Kd2, 3.07 x 10(-7) M. Cell surface heparan sulfate proteoglycans (HSPGs) were determined to serve as one class of receptors able to facilitate gB-S binding. Both HSPG-deficient Chinese hamster ovary (CHO) cells and fibroblast cells with enzymatically removed HSPGs had 40% reductions in gB-S binding, whereas removal of chondroitin sulfate had no effect. However, a significant proportion of gB-S was able to associate with the cell surface in the absence of HSPGs via an undefined nonheparin component. Binding affinity analysis of gB-S binding to wild-type CHO-K1 cells demonstrated biphasic binding kinetics (Kd1, 9.85 x 10(-6) M; Kd2, 4.03 x 10(-8) M), whereas gB-S binding to HSPG-deficient CHO-677 cells exhibited single-component binding kinetics (Kd, 7.46 x 10(-6) M). Together, these data suggest that gB-S associates with two classes of cellular receptors. The interaction of gB with its receptors is physiologically relevant, as evidenced by an inhibitory effect on HCMV entry when cells were pretreated with purified gB-S. This inhibition was determined to be manifested at the level of virus attachment. We conclude that gB is a ligand for HCMV that mediates an interaction with a cellular receptor(s) during HCMV infection.

Expression, purification, and characterization of a soluble form of human cytomegalovirus glycoprotein B

The human cytomegalovirus glycoprotein B gene (gB; gpUL55) was truncated at amino acid 692 and recombined into Autographa californica nuclear polyhedrosis virus (baculovirus). Infection of insect cells with the recombinant baculovirus resulted in high-level expression and secretion of the truncated gB protein (gB-S) into the culture medium. Purification of gB-S by monoclonal antibody affinity chromatography yielded a protein of ca. 200 kDa. Characterization of the 200-kDa purification product indicated that the recombinant gB protein retained many structural and functional features of the viral gB. Comparison of electrophoretic migration patterns in reduced versus nonreduced protein samples and immune blotting analysis with antibodies specific for the amino or carboxy-terminus of gB demonstrated that the recombinant protein was composed of disulfide linked 69 kDa amino terminal and 35-kDa carboxy-terminal fragments. In addition, recognition of the 200-kDa gB-S by a conformational-dependent, oligomer-specific monoclonal antibody suggested that gB-S was properly folded and dimeric. Like the viral gB, gB-S had heparin binding ability. One heparin binding site was found to reside within the 35-kDa carboxy-terminal fragment (aa 492-692). Heparin binding was abolished when gB-S was denatured. These data suggest that gB contains a novel heparin binding motif that is at least partially conformational dependent.

Direct interaction between human cytomegalovirus glycoprotein B and cellular annexin II

Cellular annexin II has been shown to specifically bind human cytomegalovirus (HCMV) and be a component of highly purified virions. In this report, we characterize the interaction of annexin II with HCMV. We found that the binding of annexin II to the HCMV envelope occurs partially through the calcium-dependent phospholipid-binding ability of annexin II since some annexin II was dissociated from virions with chelating agents. However, a substantial proportion of virion-associated annexin II was resistant to chelation, which suggested a calcium-independent interaction between annexin II and an HCMV envelope component. The search for a nonphospholipid component to account for this binding led to the discovery that HCMV glycoprotein B (gpUL55) (gB) can physically interact with annexin II. We present three lines of evidence to support the conclusion that HCMV gB can bind host cell annexin II.

Failure to complement infectivity of EBV and HSV-1 glycoprotein B (gB) deletion mutants with gBs from different human herpesvirus subfamilies

Glycoprotein B (gB) is conserved among the herpesvirus family which infects a broad range of species. To investigate the functional homology of human alpha-herpesviruses, beta-herpesviruses, and gamma-herpesviruses gB proteins, complementation studies were performed with gB genes from each subfamily member using EBV gp110 (EBV gB homologue) and HSV-1 gB null mutants. Neither the alpha-herpesvirus HSV-1 gB gene nor the beta-herpesvirus HCMV gB gene were able to complement the gp110 null mutant. Conversely, neither the beta-herpesvirus HCMV gB or the gamma-herpesvirus EBV gp110 gene were able to complement HSV-1 gB null mutants. To further investigate functional domains of EBV gp110 and HSV-1 gB, gB-gp110 chimeric proteins were constructed. Surprisingly, none of the chimeric proteins were able to complement either HSV-1 gB null mutants or EBV gp110 null mutants. These results demonstrate that there is not sufficient functional homology between the different gBs to allow complementation in other subfamily members of the herpesvirus family.

Characterization of a novel third member of the human cytomegalovirus glycoprotein H-glycoprotein L complex

A prerequisite for understanding the molecular function of the human cytomegalovirus (HCMV) gH (UL75)-gL (UL115) complex is a detailed knowledge of the structure of this complex in its functional form, as it is present in mature virions. The gH protein is known to be a component of a 240-kDa envelope complex designated as gCIII (D. R. Gretch, B. Kari, L. Rasmussen, R. C. Gehrz, and M. F. Stinski, J. Virol. 62:875-881, 1988). However, the exact composition of the gCIII complex remains unknown. In this report, we attempted reconstitution of the gCIII complex by coexpression of gH and gL in the baculovirus expression system. Formation of recombinant gH-gL complexes of approximately 115 kDa was demonstrated; however, no higher-molecular-mass (approximately 240-kDa) recombinant gH-gL complexes were detected, suggesting that the presence of gH and gL alone is not sufficient for reconstitution of the gCIII complex. To identify other mammalian and/or HCMV factors which may be necessary for gCIII formation, immunoprecipitates of gH and gL from HCMV-infected fibroblasts and purified HCMV virions were examined. This analysis did reveal a number of coprecipitating proteins which associate either transiently or integrally with gH and gL. One coprecipitating protein of 145 kDa was shown to be an integral component of gCIII, along with gH and gL. Characterization of the 145-kDa protein demonstrates that it is structurally and antigenically unrelated to gH and gL and that it appears to be virally encoded. Together, these data indicate that the 145-kDa protein is a third novel component of the mature HCMV gH-gL complex.

Cladistic analysis of dental traits in recent humans using a fossil outgroup

The relationships between a range of modern human samples are assessed from cladistic analyses of the published population frequencies of tooth crown characters, using new data on the Krapina Neanderthal sample as an outgroup. All of the most parsimonious trees show an early divergence of African and Australasian groups. This result is compared with an alternative dendrogram proposed by Turner (1992). Reconstruction of a hypothetical dental ancestor suggests that the similarities between the African and Australasian groups result from the retention of symplesiomorphous dental traits. Additionally, despite expectations from multiregional evolution, recent Europeans are dentally less like the Krapina Neanderthals than are Africans and Australians.

Human papilloma virus E6/E7 genes can expand the lifespan of human corneal fibroblasts

Human corneal fibroblasts were infected with a retroviral delivery vector containing the E6 and E7 genes from human Papilloma virus type 16 in order to produce cell lines that have an expanded lifespan in culture. Morphologically, some of the transfected corneal fibroblast lines appeared to have the normal spindle-shape morphology of diploid fibroblasts, whereas other lines appeared to have a more elongated morphology. All the cell lines were anchorage-dependent. Cells that had a normal morphology grew at a rate similar to normal diploid human corneal fibroblasts and had a population doubling time of 48 h. All E6/E7 expressing cell lines, regardless of morphology, produce types I, III, and V collagen, at levels similar to those observed in the parent corneal diploid fibroblast. These corneal fibroblast lines will be a useful in vitro system to study collagen expression and fibril formation, as well as normal stroma development. These results also demonstrate that the use of E6/E7 genes to expand a cell's lifespan can be a powerful tool because it does not appear to alter either the growth rate of the cell or collagen expression.

An immortalized human fibroblast cell line is permissive for human cytomegalovirus infection

Human foreskin fibroblasts (HFF) were immortalized via retrovirus-mediated gene transfer of the E6 and E7 genes of human papillomavirus type 16. An immortalized fibroblast (IF) cell line which was morphologically akin to the parental cell line was isolated. The IF cell line was evaluated for permissiveness to human cytomegalovirus (HCMV) infection after the IF cell line surpassed the normal passage limitation of diploid fibroblasts. Western immunoblot analysis of representative HCMV-encoded immediate-early (72-kDa), early (gB), and late (gH) gene products demonstrated that the IF cell line produced these proteins analogous to those produced by the parental HFF cells. Similar quantities of infectious virus were produced in the IF and HFF cell lines as determined in one-step growth curve experiments. Compared with the HFF cells, morphologically identical plaques were produced in the IF cell line in approximately 10 to 12 days postinfection. These findings indicate that fibroblast cell lines immortalized with transforming genes of human papillomavirus retain complete permissiveness to HCMV infection and support plaque formation. The IF cell line will be useful for future genetic analysis of HCMV.

Initiation of human cytomegalovirus infection requires initial interaction with cell surface heparan sulfate

In this report, we demonstrate that the initial event in human cytomegalovirus (HCMV) infection is attachment to extracellular heparan sulfate. Further, this interaction is important for initiation of infection in fibroblast cells. Using microbinding assays to specifically monitor virus attachment as well as plaque titration assays to measure infectivity, we found that heparin competition as well as enzymatic digestion of cells with heparinase blocked virus attachment, initiation of immediate-early gene expression and infectivity. Other major glycosaminoglycans were found not to be involved in HCMV attachment and infectivity. In addition, HCMV was unable to attach to mutant derivatives of Chinese hamster ovary cells deficient in synthesis of heparan sulfate proteoglycans. Basic fibroblast growth factor, which requires initial interaction with extracellular heparin prior to binding to its high affinity receptor, also inhibited HCMV attachment to cells. Time-course experiments revealed that the initial HCMV binding was sensitive to heparin competition (10 micrograms/ml) or 0.75 M salt washes. The initial heparin-dissociable binding converted rapidly to high affinity (heparin resistant) HCMV attachment. These data suggest that sequential receptor interactions may mediate HCMV adsorption to cells. Heparin affinity chromatography revealed that multiple HCMV envelope glycoproteins, including gB, are capable of binding to heparin.

Human cytomegalovirus penetrates host cells by pH-independent fusion at the cell surface

Biochemical, genetic, and morphological criteria were used to demonstrate that human cytomegalovirus penetrates permissive fibroblasts and nonpermissive Chinese hamster ovary (CHO) cells by pH-independent fusion between the virus envelope and the host cell plasma membrane and not by low pH-induced fusion within endosomes. Viral immediate early (IE) gene expression and infectivity were unaffected by conditions which block various stages of endocytosis or agents that alter the acidic pH of the endosome. IE gene expression was also evident in a mutant CHO cell line which is defective in endosomal acidification. Morphological analysis of the entry process at the electron microscopic level revealed viral particles in various stages of virion-plasma membrane fusion. In contrast, intact enveloped virions were not observed sequestered within coated pits or vesicular structures. Collectively, the data indicate that the entry pathway by which HCMV gains access to the cytoplasm of fibroblasts and CHO cells in order to initiate infection is via pH independent, virion envelope-plasma membrane fusion.

Expression of a human cytomegalovirus receptor correlates with infectibility of cells

Previous studies have demonstrated that human cytomegalovirus (HCMV) specifically binds to a fibroblast membrane glycoprotein(s) with a molecular mass from 30 to 34 kDa. In this study, the distribution of the putative receptor proteins was analyzed in a variety of cell types, including cell types representative of those that are infected in vivo. Using a sensitive microbinding assay (to score virus attachment) and an indirect detection method (to score HCMV-binding proteins), we found that the 34- and 32-kDa HCMV binding proteins are ubiquitous molecules, broadly distributed among diverse cell types. In addition, the level of virus attachment was found to correlate with the abundance of the 34- and 32-kDa cellular proteins, while the ability of the virus to penetrate cells and initiate infection did not. The results support the hypothesis that the 34- and 32-kDa cellular proteins represent the HCMV (attachment) receptor. The data also support the notion that additional cellular components are required for virus entry and fusion.

Cellular receptor for human cytomegalovirus

The results of the studies reported strongly suggest that the binding of HCMV to a target cell in vitro is mediated by a glycoprotein membrane receptor having a molecular weight of approximately 30 kd. It has been further concluded that this particular molecule is the principal HCMV receptor, since it has been observed in each of the cell types that have been studied. As for the 28 and 60 kd molecules, the former may be a proteolytic degradation product and the latter a dimer of the 30 kd receptor. The precise contribution of the 92 kd that may allow for viral penetration into a host cell molecule to the initial recognition event is unknown at the present time.

Identification of the thymidine kinase gene of feline herpesvirus: use of degenerate oligonucleotides in the polymerase chain reaction to isolate herpesvirus gene homologs

Feline herpesvirus 1 (FHV) is the causative agent of viral rhinotracheitis in cats. Current vaccination programs employing attenuated live and killed FHV vaccines have been effective in reducing the incidence of this disease. As an initial step in the development of recombinant FHVs for use in the vaccination of cats, we have identified the thymidine kinase (TK) gene of this feline-specific alphaherpesvirus. Comparisons of the amino acid sequences of other herpesvirus TK proteins have shown that these proteins are highly divergent, sharing only short regions of imperfect amino acid identity. We have used the polymerase chain reaction method of DNA amplification to increase the specificity associated with the use of short, highly degenerate oligonucleotide probes derived from regions of imperfect amino acid conservation. These methods were used to isolate the TK gene of FHV and should prove to be useful in the identification of new members of other viral and cellular gene families. A recombinant FHV bearing a deletion in the identified TK gene was constructed and shown to possess the expected TK- phenotype. The FHV TK gene is located at a position of approximately 40% in the long unique component of the FHV genome. The location of the TK gene and the location and orientation of flanking FHV genes, homologs of herpes simplex virus type 1 UL24 and UL22, are conserved among alphaherpesviruses.

A sorting signal for the basolateral delivery of the vesicular stomatitis virus (VSV) G protein lies in its luminal domain: analysis of the targeting of VSV G-influenza hemagglutinin chimeras

When synthesized in polarized epithelial cells, the envelope glycoproteins hemagglutinin of influenza and G of vesicular stomatitis virus are targeted to the apical and basolateral plasma membranes, respectively. To determine which portions of these transmembrane proteins contain information necessary for their sorting, the behavior of two different G-hemagglutinin chimeric polypeptides, consisting of all or nearly all the luminal portion of the vesicular stomatitis virus G protein linked to C-terminal segments of influenza hemagglutinin that included its transmembrane and cytoplasmic domains, was studied in MDCK cells transformed with the corresponding cDNAs. Both chimeras were transported from the endoplasmic reticulum to the Golgi apparatus and from there to the cell surface with the same rapid kinetics as the intact G protein. By using a cell surface immunoprecipitation assay with monolayers cultured on permeable filters that allows the recovery of labeled protein molecules present in each cell surface domain, it was found that both chimeric proteins as well as the intact G protein were delivered almost exclusively to the basolateral surface. This polarized distribution of the polypeptides did not change during a subsequent 90-min chase period, although during this time a large fraction of the glycoprotein molecules underwent degradation. In addition, a small fraction of the cell surface-associated glycoprotein molecules shed their ectoplasmic segments into the basolateral compartment, apparently as a result of a proteolytic cleavage. Immunofluorescence on transverse frozen sections and immunoelectron microscopy revealed a prominent accumulation of the chimeric polypeptides in the lateral cell membranes, with lesser amounts on the basal and apical surfaces. These results indicate that information specifying the basolateral transport of the G glycoprotein is located within the first 426 N-terminal amino acids of its ectoplasmic portion.

Detection of Epstein-Barr virus DNA by polymerase chain reaction in blood and tissue biopsies from patients with Sjogren's syndrome

Polymerase chain reaction has been used to detect increased levels of EBV DNA in salivary gland (SG) biopsies and PBL from patients with Sjogren's syndrome (SS). These results suggest that EBV, which has a normal site of latency in a small number of SG epithelial cells, may be reactivated in SS patients and provide a target for immune attack. The great sensitivity of polymerase chain reaction (PCR) and the ability to analyze very small tissue biopsies (37) make this technique well suited for clinical diagnosis. Specific methods to prevent artefactual contamination of tissue biopsy DNA with viral DNA of other samples (i.e., lyophilization of samples before DNA extraction) and the use of an internal positive control (i.e., inclusion of primers for a single copy human gene) during PCR amplification are presented. Since EBV reactivation occurs with markedly increased frequency in patients with lymphoproliferative and immunodeficiency diseases, as well as transplant recipients receiving cyclosporin A (10), rapid methods of viral detection such as PCR may allow better monitoring of medications and early detection of EBV-related lymphomas that may arise in these patients.

Use of DNA amplification methods for clinical diagnosis in autoimmune diseases

Autoimmune disease is generally felt to result from the interaction of genetic and environmental factors. In recent years, significant advances have been made in using recombinant DNA methods to analyze specific genetic factors and infectious agents. However, new techniques are needed that are more rapid, inexpensive, and suitable for small tissue biopsies obtained early in the course of disease. New methods of DNA amplification based on polymerase chain reaction (PCR) and Q beta-replicase (Q beta R) have recently been reported. These methods are briefly reviewed, and their potential applications to patients with autoimmune disease are presented. Several types of applications can be considered, including detection of: a) specific HLA-D alleles in order to predict prognosis and better utilize existing medications; b) bacterial, fungal, and spirochete infections in joint aspirates or synovial biopsies; c) human immunodeficiency virus (HIV) and other viruses (e.g., EBV, CMV) that may be associated with immune dysregulation in certain patients; and d) neoplastic transformation in blood or tissues by determining monoclonal gene rearrangements, karyotypic alterations or oncogene activation. It is likely that routine clinical laboratories will soon begin implementing DNA amplification methods in order to screen blood products for infectious agents (especially HIV and hepatitis B virus). Because these techniques will be readily available, rheumatologists/clinical immunologists should begin developing strategies that will allow them to use these methods in a cost-effective manner for diagnosis and monitoring treatment.

Effect of herpes simplex virus type 1 on cellular pools of oligosaccharide-lipid

Incorporation of [3H]mannose into cellular pools of mannosylphosphoryl dolichol (Man-P-Dol), oligosaccharide-lipid, and glycoprotein was measured and compared in herpes simplex virus type 1 (HSV-1)-infected cells and -uninfected cells. While mannose incorporation into the monosaccharide-dolichol fraction was similar in infected or uninfected Vero cells, incorporation into the oligosaccharide-lipid fraction was markedly reduced in HSV-1-infected cells (64% of control levels). In contrast, mannose incorporation into glycoprotein was significantly increased in virus-infected cells versus uninfected cells (194% of control levels). The kinetics of incorporation into the various fractions was examined and it was determined that there was minimal increase in mannose incorporation into oligosaccharide-lipid after 8 hr postinfection in virus-infected cells. This corresponded to the time at which nonglycosylated precursors of the HSV-1 glycoproteins were first detected in association with the nuclear fraction. These data suggest that there is an accelerated turnover of oligosaccharide-lipid in virus-infected Vero cells which is most likely due to extensive glycoprotein synthesis.

Evidence for post-translational glycosylation of a nonglycosylated precursor protein of herpes simplex virus type 1

Incubation of herpes simplex virus type 1-infected Vero and HEp-2 cells at a reduced temperature (34 degrees C) enhanced the detection of the nonglycosylated precursors (pgB97 and pgC75) to the gB and gC glycoproteins in the cytoplasmic and nuclear fractions. Relative to the fully glycosylated and high-mannose forms detected, the nonglycosylated precursors were the predominant components associated with the nuclear fraction of infected cells. Furthermore, addition of protease inhibitors to the fractionation buffers did not affect the distribution or abundance of the nonglycosylated precursors, suggesting that the presence of pgB97 and pgC75 was not the result of proteolysis. When infected Vero or HEp-2 cells were harvested at various times postinfection, the nonglycosylated precursors were detected after the initial appearance of the high mannose components (pgB110 and pgC105). In Vero cells, pgB97 and pgC75 were detected simultaneously at 8 h postinfection, whereas detection was not apparent in HEp-2 cells until 20 h postinfection. Conditions which favored detection of appreciable amounts of nonglycosylated precursors provided an unique approach to probe possible post-translational modifications in the absence of inhibitors of glycosylation. In nuclear fractions isolated from cycloheximide-treated HEp-2 or Vero cells, numerous discrete gC-immunoreactive bands migrating with decreased electrophoretic mobility relative to the nonglycosylated precursor pgC75 were observed. This series of one to four additional bands was eliminated by digestion with endoglycosidase H, and the appearance of these bands was blocked by the addition of tunicamycin. Collectively, the data suggest that high-mannose core oligosaccharides may be added to the nonglycosylated precursor of the gC glycoprotein of herpes simplex virus type 1 in a post-translational fashion.

Virus-specific glycoproteins associated with the nuclear fraction of herpes simplex virus type 1-infected cells

Monospecific antisera to herpes simplex virus type 1 (HSV-1) glycoproteins gB, gC, and gD were used to identify the HSV-1-specific glycoproteins associated with the nuclear fraction as compared with those associated with cytoplasmic fraction, whole-cell lysates, and purified virions. The results indicate that a predominance of HSV glycoprotein precursors pgC(105), pgB(110), and pgD(52) is associated with the nuclear fraction. Treatment of the nuclear fraction with the enzyme endo-beta-N-acetylglucosaminidase H indicated that the lower-molecular-weight glycoproteins are sensitive to this endoglycosidase. These results suggest that in the nuclear fraction of HSV-1-infected cells virus-specific glycoproteins gB, gC, and gD are predominately in the high-mannose precursor form; however, detectable amounts of the fully glycosylated forms of gC and gD were also found.