The weights and ginsenoside levels of twenty 4-year-old American ginseng (Panax quinquefolius) roots harvested from a homogeneous-looking 1-m2 plot were determined. It was found that the dry weight of the roots ranged from 3.5 to 22.8 g, a factor of 6.5; whereas the ginsenoside levels of these roots ranged from 24.7 to 56.4 μmol/g, a factor of 2.3. Further, it was found that the larger plants also contained higher ginsenoside levels on a weight basis. This finding is based, in part, on the ginsenosides in P. quinquefolius being located in both the periderm and cortex and the xylem and pith portions of the root. As the environmental variation experienced by the plants analyzed in this study was minimized, a portion of the variation found in these traits is likely to be a result of genetic diversity within the crop. These findings indicate that a cultivar of P. quinquefolius could be developed that would yield plants that have both an average weight and ginsenoside level per gram of tissue substantially greater than that of the existing crop. Keywords: Panax quinquefolius, American ginseng, ginsenosides, genetic selection.

UL69 of human cytomegalovirus (HCMV) encodes a pleiotropic transactivator protein and has a counterpart in every member of the Herpesviridae family thus far sequenced. However, little is known about the conservation of the functions of the nuclear phosphoprotein pUL69 in the homologous proteins of other betaherpesviruses. Therefore, eukaryotic expression vectors were constructed for pC69 of chimpanzee cytomegalovirus, pRh69 of rhesus cytomegalovirus, pM69 of murine cytomegalovirus, pU42 of human herpesvirus 6, and pU42 of elephant endotheliotropic herpesvirus. Indirect immunofluorescence experiments showed that all pUL69 homologs expressed by these vectors were localized to the cell nucleus. Coimmunoprecipitation experiments identified homodimerization as a conserved feature of all homologs, whereas heterodimerization with pUL69 was restricted to its closer relatives. Further analyses demonstrated that pC69 and pRh69 were the only two homologs that functioned, like pUL69, as viral-mRNA export factors. As we had reported recently that nucleocytoplasmic shuttling and interaction with the cellular DExD/H-box helicases UAP56 and URH49 were prerequisites for the nuclear-mRNA export activity of pUL69, the homologs were characterized with regard to these properties. Heterokaryon assays demonstrated nucleocytoplasmic shuttling for all homologs, and coimmunoprecipitation and mRNA export assays revealed that the interaction of UAP56 and/or URH49 with pC69 or pRh69 was required for mRNA export activity. Moreover, characterization of HCMV recombinants harboring mutations within the N-terminal sequence of pUL69 revealed a strong replication defect of viruses expressing pUL69 variants that were deficient in UAP56 binding. In summary, homodimerization and nucleocytoplasmic shuttling activity were identified as conserved features of betaherpesviral pUL69 homologs. UAP56 binding was shown to represent a unique characteristic of members of the genus Cytomegalovirus that is required for efficient replication of HCMV.On the basis of biological properties, genome structure, and comparisons of primary amino acid sequences, the family Herpesviridae has been subdivided into three subfamilies, the Alpha-, Beta-and Gammaherpesvirinae (Fig. 1A) (40). Separation of these subfamilies is estimated to have proceeded approximately 180 to 200 million years ago (12), with development of genera within each subfamily occurring by more recent events (32). The subfamily Betaherpesvirinae contains four genera, Cytomegalovirus, Muromegalovirus, Roseolovirus, and Proboscivirus (Fig. 1A). The most intensively studied betaherpesviruses belong to the genus Cytomegalovirus and include human cytomegalovirus (HCMV; species, Human herpesvirus 5), rhesus cytomegalovirus (RhCMV; species, Macacine herpesvirus 3), and chimpanzee cytomegalovirus (CCMV; species, Panine herpesvirus 2). The genus Muromegalovirus comprises murine cytomegalovirus (MCMV; species, Murid herpesvirus 1) and rat cytomegalovirus (RCMV; species, Murid herpesvirus 2). Human herpesvirus 6 (HHV6...

Although the value placed on theoretical work in psychology has diminished over recent years, new and significant challenges to the status of theory have emerged within the intellectual community more generally. The demise of the mapping metaphor, the reduction of reason to rhetoric, and the recognition of the impossibility of value-neutral theorizing all raise questions concerning the status and function of theory. Critical theory in psychology has provided one response to these issues by employing theory as an emancipatory device. However, given the limits to pure critique, many search for means of employing theory in the service of pro-active practices of social change. Given the various problems of theory in the traditional mold, what is the function and status of theory in these emerging practices? In the present issue, we bring together five explorations of the utility of theory in processes of social action. Pivotal in these offerings is the reconceptualization of theory as a form of discursive action. When viewed in this light, new and important issues emerge in our understanding of theoretical work and its place in both intellectual and social life.

The regulatory protein pUL69 of human cytomegalovirus acts as a viral mRNA export factor, facilitating the cytoplasmic accumulation of unspliced RNA via interaction with the cellular mRNA export factor UAP56. Here we provide evidence for a posttranslational modification of pUL69 via arginine methylation within the functionally important N terminus. First, we demonstrated a specific immunoprecipitation of full-length pUL69 as well as pUL69aa1-146 by a mono/dimethylarginine-specific antibody. Second, we observed a specific electrophoretic mobility shift upon overexpression of the catalytically active protein arginine methyltransferase 6 (PRMT6). Third, a direct interaction of pUL69 and PRMT6 was confirmed by yeast two-hybrid and coimmunoprecipitation analyses. We mapped the PRMT6 interaction motif to the pUL69 N terminus and identified critical amino acids within the arginine-rich R1 box of pUL69 that were crucial for PRMT6 and/or UAP56 recruitment. In order to test the impact of putative methylation substrates on the functions of pUL69, we constructed various pUL69 derivatives harboring arginine-to-alanine substitutions and tested them for RNA export activity. Thus, we were able to discriminate between arginines within the R1 box of pUL69 that were crucial for UAP56/PRMT6-interaction and/or mRNA export activity. Remarkably, nuclear magnetic resonance (NMR) analyses revealed the same ␣-helical structures for pUL69 sequences encoding either the wild type R1/R2 boxes or a UAP56/PRMT6 binding-deficient derivative, thereby excluding the possibility that R/A amino acid substitutions within R1 affected the secondary structure of pUL69. We therefore conclude that the pUL69 N terminus is methylated by PRMT6 and that this critically affects the functions of pUL69 for efficient mRNA export and replication of human cytomegalovirus. IMPORTANCEThe UL69 protein of human cytomegalovirus is a multifunctional regulatory protein that acts as a viral RNA export factor with a critical role for efficient replication. Here, we demonstrate that pUL69 is posttranslationally modified via arginine methylation and that the protein methyltransferase PRMT6 mediates this modification. Furthermore, arginine residues with a crucial function for RNA export and for binding of the cellular RNA export factor UAP56 as well as PRMT6 were mapped within the arginine-rich R1 motif of pUL69. Importantly, we demonstrated that mutation of those arginines did not alter the secondary structure of R1, suggesting that they may serve as critical methylation substrates. In summary, our study reveals a novel posttranslational modification of pUL69 which has a significant impact on the function of this important viral regulatory protein. Since PRMTs appear to be amenable to selective inhibition by small molecules, this may constitute a novel target for antiviral therapy. E very mammalian or avian herpesvirus encodes a member of the ICP27 protein family which functions as a posttranscriptional activator by facilitating the nuclear export of intronless mRNAs ...

Nucleocytoplasmic shuttling and interaction with the cellular mRNA export factor UAP56 are prerequisites for the mRNA export activity of human cytomegalovirus (HCMV) pUL69. Although the murine cytomegalovirus homolog pM69 shuttles, it fails to export mRNAs due to its inability to recruit UAP56. However, chimeric proteins comprising pM69 fused to N-terminal pUL69 fragments, including its UAP56 interaction motif, acquire mRNA export activity. Importantly, growth curves of recombinant HCMVs illustrate that such a chimeric protein, but not pM69, substitutes for pUL69 during HCMV infection.