Interactions Among Murine Cytomegalovirus US22 Family Gene Products That Influence Viral Pathogenesis

Cytomegalovirus (CMV) is a complex, ubiquitous herpesvirus that is characterized by acute, chronic, and latent infections. Monocytes-macrophages are the key target cell type involved in pathogenesis, which is most effectively studied using the murine model of CMV infection. Previously three murine CMV (MCMV) genes (M139, M140, and M141) were identified to regulate viral expression in cultured macrophages and in mice. These genes are members of the US22 gene family with respect to HCMV homology. There is no function assigned to the proteins encoded by these genes. However, deletion of M139, M140, and M141 significantly curtails growth of MCMV in macrophages in vitro and in macrophage-dense target organs in vivo (Hanson et al. 1999, J.Virol. 73(7): 5970–80). Therefore, M139, M140, and/or M141 gene products likely affect tissue specific viral infectivity. The purpose of this study was to characterize these proteins (pM139, pM140, and pM141) and interaction among them. The M139, gene encodes two protein of 75 and 61 kD; M140 encodes a single protein of 56 kD, and M141 encodes a 52 kD protein. Most interestingly, when infected cell lysates were immunoprecipitated with anti-M139 antibody under non-denaturing (but not denaturing) conditions, five bands of 98-, 75-, 61-, 56-, and 52-kD proteins were co-precipitated. Likewise, anti-M140 antisera co-precipitated two bands of 56- and 52-kD, and anti-M141 antibody precipitated a less abundant 56- and an abundant 52-kD band. The co-precipitating bands were identified as products of M139, M140, and M141 genes in experiments employing mutant viruses deleted of each gene. Complex formation between the M140 and M141 proteins (PM140 and pM141) was confirmed by sequential immunoprecipitations and combined immunoprecipitation and western blotting. These two proteins also formed a complex in the absence of other viral proteins. At least one function of the pM140/pM141 complex is to stabilize expression of pM141, which is unstable in the absence of pM140. Given the complexity of viral pathogenesis and the fact that pM139, pM140, and pM141 proteins are dispensable for viral replication in tissue culture, it is possible that each single protein as well as the complex(s) they form may have a distinct function which influences tissue specific infectivity

Screening revealed the strong cytotoxic activity of <i>Alchemilla smirnovii</i> and <i>Hypericum alpestre</i> ethanol extracts on different cancer cell lines

Compounds of plant origin are considered promising alternative approaches in the development of medicines for the prevention and treatment of cancer. The large diversity of herbal species still requires careful exploration as a source for new anticancer compounds. The goal of the study was to screen different herbal extracts traditionally used in Armenian folk medicine for their cytotoxic effect against some cancer cell lines, and to find the prospective plant species among them. The cytotoxicity of the plant ethanol extracts was evaluated with MTT test against HeLa (human cervical carcinoma) and A549 (human lung adenocarcinoma) cells. Antioxidant properties were assessed with DPPH free radical scavenging assay. Five of the tested ten herbal extracts exhibited significant growth-inhibiting activity on HeLa cells. Moreover, Alchemilla smirnovii and Hypericum alpestre extracts also showed potent cytotoxicity on human lung adenocarcinoma cells. These two plants possessed high antiradical activity as well. Their DPPH stoichiometric values were 0.4234 and 0.14437 respectively, meaning that 1 µg of plant extract brought the reduction of DPPH equal to the respective stoichiometric values in µg. Thus, A. smirnovii and H. alpestre extracts expressed themselves as potent cytotoxic and antioxidant agents and could have promising anticancer potential. Further evaluation of their in vivo anticancer properties has much interest

Formation of cardiac fibers in Matrigel matrix

The Rangelands archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform March 202

Clinically relevant concentrations of di (2-ethylhexyl) phthalate (DEHP) uncouple cardiac syncytium

Di(2-ethylhexyl) phthalate (DEHP) is a widely used plasticizer found in a variety of polyvinyl chloride (PVC) medical products. The results of studies in experimental animals suggest that DEHP leached from flexible PVC tubing may cause health problems in some patient populations. While the cancerogenic and reproductive effects of DEHP are well recognized, little is known about the potential adverse impact of phthalates on the heart. This study examined the effects of clinically relevant concentrations of DEHP on neonatal rat cardiomyocytes. It was found that application of DEHP to a confluent, synchronously beating cardiac cell network, leads to a marked, concentration-dependent decrease in conduction velocity and asynchronous cell beating. The mechanism behind these changes was a loss of gap junctional connexin-43, documented using western blot analysis, dye-transfer assay and immunofluorescence. In addition to its effect on electrical coupling, DEHP treatment also affected the mechanical movement of myocyte layers. The latter was linked to the decreased stiffness of the underlying fibroblasts, as the amount of triton-insoluble vimentin was significantly decreased in DEHP-treated samples. The data indicate that DEHP, in clinically relevant concentrations, can impair the electrical and mechanical behavior of a cardiac cell network. Applicability of these findings to human patients remains to be established

Complex Formation among Murine Cytomegalovirus US22 Proteins Encoded by Genes M139, M140, and M141

The murine cytomegalovirus (MCMV) proteins encoded by US22 genes M139, M140, and M141 function, at least in part, to regulate replication of this virus in macrophages. Mutant MCMV having one or more of these genes deleted replicates poorly in macrophages in culture and in the macrophage-dense environment of the spleen. In this report, we demonstrate the existence of stable complexes formed by the products of all three of these US22 genes, as well as a complex composed of the products of M140 and M141. These complexes form in the absence of other viral proteins; however, the pM140/pM141 complex serves as a requisite binding partner for the M139 gene products. Products from all three genes colocalize to a perinuclear region of the cell juxtaposed to or within the cis-Golgi region but excluded from the trans-Golgi region. Interestingly, expression of pM141 redirects pM140 from its predominantly nuclear residence to the perinuclear, cytoplasmic locale where these US22 proteins apparently exist in complex. Thus, complexing of these nonessential, early MCMV proteins likely confers a function(s) independent of each individual protein and important for optimal replication of MCMV in its natural host

Transcriptional analysis of the murine cytomegalovirus HindIII-I region: Identification of a novel immediate early gene region

AbstractCytomegaloviruses likely encode numerous gene products involved in regulating virus–host cell interactions and pathogenesis. We previously identified a region of murine cytomegalovirus (MCMV) within HindIII-J and -I that regulates pathogenesis of the virus [open reading frames (ORFs) M139–M141] or is likely required for MCMV replication (ORFs m142 and m143). As a prerequisite for further studies on the structure and function of this gene region, we mapped the transcripts encoded within MCMV HindIII-I. Probes for ORFs M140 and M141 hybridized to 5.4- and 7.0-kb RNA, respectively, which were transcribed with early kinetics and were 3′ coterminal with HindIII-J ORF M139. Probes representing ORFs m142, m143, or m144 hybridized to 3′ coterminal transcripts of 1.8, 3.8, and 5.1 kb, respectively. ORFs m142 and m143 were transcribed with immediate-early kinetics but were most abundantly expressed at early times. Probes for the rightmost end of HindIII-I hybridized to a 5.1-kb early/late RNA corresponding to m144 and to a 1.8-kb early RNA transcribed from m145. All of the major transcripts were polyadenylated and therefore are likely coding. Additional minor transcripts of intermediate sizes were also detected. ORFs M139–m143 showed homology to the betaherpesvirus-specific HCMV US22 gene family. Because deletion of these viral genes results in attenuated or helper-dependent phenotypes, this conserved region of US22 family genes may have a role in virus replication as well as in the pathogenesis of betaherpesviruses in their natural hosts