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Publication
Journal: Biology of Reproduction
October/5/2008
Abstract
Embryo implantation is a complex process involving blastocyst attachment to the endometrial epithelium and subsequent trophoblast invasion of the decidua. We have previously shown that the chemokines CX3CL1 and CCL14 are abundant in endometrial vasculature, epithelial, and decidual cells at this time, and that their receptors, CX3CR1 and CCR1, are present on invading human trophoblasts. CX3CL1 and CCL14 promote trophoblast migration. We hypothesized that these endometrial chemokines promote trophoblast migration by regulating adhesion molecules and extracellular matrix (ECM) components on the trophoblast, similar to mechanisms used in leukocyte trafficking. Trophoblast cells (AC1M-88) used previously showed a marked increase in adhesion to fibronectin following treatment with CX3CL1 and CCL14. Alterations in trophoblast adhesion and ECM following chemokine stimulation were examined using pathway-specific oligo-arrays and quantitative real-time RT-PCR. More than 30 genes were affected by CX3CL1 treatment, and 15 genes were found to be regulated by CCL14 treatment. Real-time RT-PCR quantitation revealed significant changes in the mRNA transcripts of alpha-catenin (CTNNA1), extracellular matrix protein 1 (ECM1), osteopontin (SPP1), integrin alpha 6 (ITGA6), matrix metalloproteinase 12 (MMP12), and integrin beta 5 (ITGB5) following chemokine treatment. Several of these genes have previously been implicated in implantation. Immunohistochemistry confirmed the presence of integrin alpha 6 and SPP1 protein in first-trimester human implantation sites. The temporal and spatial expression of chemokines, their receptors, adhesion, and ECM at the maternal-fetal interface emphasizes an important role in the controlled directional migration of trophoblasts through the maternal decidua. For the first time, this study demonstrates the direct effects of CX3CL1 and CCL14 on trophoblast adhesion molecules and ECM, suggesting mechanisms by which trophoblast cells migrate during early pregnancy.
Publication
Journal: OncoImmunology
November/18/2017
Abstract
Understanding interactions between tumor and the host immune system holds great promise to uncover biomarkers for targeted therapies and clinical outcomes. However, systematical analysis of immune signatures in esophageal squamous cell carcinoma (ESCC) remains largely unstudied. In this study, immune signatures containing 708 immune related genes were curated from mRNA microarray data with tumor and paired normal tissues from 119 ESCC patients. Differential expression and survival analysis were performed with validations from Human Protein Atlas and an independent cohort of 110 ESCC patients by immunohistochemistry staining. We identified a total of 186 significantly dysregulated genes in ESCC, including downregulated genes SPINK5, IL1RN and upregulated genes SPP1 and PLAU, which were further confirmed in Human Protein Atlas data. Moreover, nine immune related genes (ABL1, ATF2, ATG5, C6, CD38, HMGB1, ICOSLG, IL12RB2 and PLAU) were significantly associated with patients' overall survival, among which, prognostic model was built including three independent factors ABL1, CD38 and ICOSLG. Validation by immunohistochemistry staining suggested that combination with tumor infiltrated CD4+ and CD8+ T lymphocytes would yield higher performance in distinguishing cases as high or low risk of unfavorable prognosis. In summary, we profiled the immune status in ESCC and established predictive and prognostic factors for ESCC, which could reflect immune disorders within tumor microenvironments and independently distinguish patients with a high risk of reduced survival, providing novel predictive and therapeutic targets for ESCC patients in the future.
Publication
Journal: Genes and Development
March/11/2014
Abstract
The stimulation of trimethylation of histone H3 Lys4 (H3K4) by H2B monoubiquitination (H2Bub) has been widely studied, with multiple mechanisms having been proposed for this form of histone cross-talk. Cps35/Swd2 within COMPASS (complex of proteins associated with Set1) is considered to bridge these different processes. However, a truncated form of Set1 (762-Set1) is reported to function in H3K4 trimethylation (H3K4me3) without interacting with Cps35/Swd2, and such cross-talk is attributed to the n-SET domain of Set1 and its interaction with the Cps40/Spp1 subunit of COMPASS. Here, we used biochemical, structural, in vivo, and chromatin immunoprecipitation (ChIP) sequencing (ChIP-seq) approaches to demonstrate that Cps40/Spp1 and the n-SET domain of Set1 are required for the stability of Set1 and not the cross-talk. Furthermore, the apparent wild-type levels of H3K4me3 in the 762-Set1 strain are due to the rogue methylase activity of this mutant, resulting in the mislocalization of H3K4me3 from the promoter-proximal regions to the gene bodies and intergenic regions. We also performed detailed screens and identified yeast strains lacking H2Bub but containing intact H2Bub enzymes that have normal levels of H3K4me3, suggesting that monoubiquitination may not directly stimulate COMPASS but rather works in the context of the PAF and Rad6/Bre1 complexes. Our study demonstrates that the monoubiquitination machinery and Cps35/Swd2 function to focus COMPASS's H3K4me3 activity at promoter-proximal regions in a context-dependent manner.
Publication
Journal: Journal of Pathology
November/26/2012
Abstract
A polymorphism (rs28357094) in the promoter region of the SPP1 gene coding for osteopontin (OPN) is a strong determinant of disease severity in Duchenne muscular dystrophy (DMD). The rare G allele of rs28357094 alters gene promoter function and reduces mRNA expression in transfected HeLa cells. To dissect the molecular mechanisms of increased disease severity associated with the G allele, we characterized SPP1 mRNA and protein in DMD muscle biopsies of patients with defined rs28357094 genotype. We did not find significant differences in osteopontin mRNA or protein expression between patients carrying the T (ancestral allele) or TG/GG genotypes at rs28357094. The G allele was significantly associated with reduced CD4(+) and CD68(+) cells on patient muscle biopsy. We also quantified transforming growth factor-β (TGFB) and TGFB receptor-2 (TGFBR2) mRNA in DMD muscle biopsies, given the ability of TGFB and TGFBR2 to activate SPP1 promoter region and their role in DMD pathogenesis. The amount of TGFB and TGFBR2 mRNA did not predict the amount of SPP1 mRNA or protein, while a polymorphism in the TGFBR2 gene (rs4522809) was found to be a strong predictor of SPP1 mRNA level. Our findings suggest that OPN mediates inflammatory changes in DMD and that TGFB signalling has a role in the complex regulation of osteopontin expression.
Publication
Journal: PLoS ONE
June/14/2014
Abstract
Our previous results with flight (FLT) mice showed abnormalities in thymuses and spleens that have potential to compromise immune defense mechanisms. In this study, the organs were further evaluated in C57BL/6 mice after Space Shuttle Atlantis returned from a 13-day mission. Thymuses and spleens were harvested from FLT mice and ground controls housed in similar animal enclosure modules (AEM). Organ and body mass, DNA fragmentation and expression of genes related to T cells and cancer were determined. Although significance was not obtained for thymus mass, DNA fragmentation was greater in the FLT group (P<0.01). Spleen mass alone and relative to body mass was significantly decreased in FLT mice (P<0.05). In FLT thymuses, 6/84 T cell-related genes were affected versus the AEM control group (P<0.05; up: IL10, Il18bp, Il18r1, Spp1; down: Ccl7, IL6); 15/84 cancer-related genes had altered expression (P<0.05; up: Casp8, FGFR2, Figf, Hgf, IGF1, Itga4, Ncam1, Pdgfa, Pik3r1, Serpinb2, Sykb; down: Cdc25a, E2F1, Mmp9, Myc). In the spleen, 8/84 cancer-related genes were affected in FLT mice compared to AEM controls (P<0.05; up: Cdkn2a; down: Birc5, Casp8, Ctnnb1, Map2k1, Mdm2, NFkB1, Pdgfa). Pathway analysis (apoptosis signaling and checkpoint regulation) was used to map relationships among the cancer-related genes. The results showed that a relatively short mission in space had a significant impact on both organs. The findings also indicate that immune system aberrations due to stressors associated with space travel should be included when estimating risk for pathologies such as cancer and infection and in designing appropriate countermeasures. Although this was the historic last flight of NASA's Space Shuttle Program, exploration of space will undoubtedly continue.
Publication
Journal: Biochemical and Biophysical Research Communications
May/14/1969
Publication
Journal: Molecular & general genetics : MGG
April/26/1976
Abstract
A total of 23 phage specific proteins (including four head and six tail proteins) could be identified after SDS polyacrylamide gel electrophoresis of extracts from phage SPP1 infected Bacillus subtilis cells. The total molecular weight of the proteins amounts to approximately 1.9 X 10(6) daltons, equivalent to the majority of the coding capacity of SPP1 DNA. It can thus be assumed that almost all SPP1 coded proteins have been identified. Protein assignments to phage cistrons were made by analysis of extracts from nonpermissive cells infected with sus-mutants. The SPP1 specified proteins can be subdivided into three groups on the basis of the time of their synthesis during the latent period. Host protein synthesis is not significantly affected by SPP1 infection. Normal expression of host genes appears to be essential for SPP1 growth.
Publication
Journal: Journal of Materials Science: Materials in Medicine
January/5/2014
Abstract
The primary objective of this study was to assess the biological effects of a new dentine substitute based on Ca₃SiO₅ (Biodentine™) for use in pulp-capping treatment, on pseudo-odontoblastic (MDPC-23) and pulp (Od-21) cells. The secondary objective was to evaluate the effects of Biodentine and mineral trioxide aggregate (MTA) on gene expression in cultured spheroids. We used the acid phosphatase assay to compare the biocompatibility of Biodentine and MTA. Cell differentiation was investigated by RT-qPCR. We investigated the expression of genes involved in odontogenic differentiation (Runx2), matrix secretion (Col1a1, Spp1) and mineralisation (Alp). ANOVA and PLSD tests were used for data analysis. MDPC-23 cells cultured in the presence of MTA had higher levels of viability than those cultured in the presence of Biodentine and control cells on day 7 (P = 0.0065 and P = 0.0126, respectively). For Od-21 cells, proliferation rates on day 7 were significantly lower in the presence of Biodentine or MTA than for control (P < 0.0001). Col1a1 expression levels were slightly lower in cells cultured in the presence of MTA than in those cultured in the presence of Biodentine and in control cells. Biodentine and MTA may modify the proliferation of pulp cell lines. Their effects may fluctuate over time, depending on the cell line considered. The observed similarity between Biodentine and MTA validates the indication for direct pulp-capping claimed by the manufacturers.
Publication
Journal: Molecular and Cellular Biology
July/18/2010
Abstract
The trans-histone regulatory cross talk between H2BK123 ubiquitination (H2Bub1) and H3K4 and H3K79 methylation is not fully understood. In this study, we report that the residues arginine 119 and threonine 122 in the H2B C-terminal helix are important for transcription and cell growth and play a direct role in controlling H2Bub1 and H3K4 methylation. These residues modulate H2Bub1 levels by controlling the chromatin binding and activities of the deubiquitinases. Furthermore, we find an uncoupling of the H2Bub1-mediated coregulation of both H3K4 and -K79 methylation, as these H2B C-terminal helix residues are part of a distinct surface that affects only Set1-COMPASS (complex proteins associated with Set1)-mediated H3K4 methylation without affecting the functions of Dot1. Importantly, we also find that these residues interact with Spp1 and control the chromatin association, integrity, and overall stability of Set1-COMPASS independent of H2Bub1. Therefore, we have uncovered a novel role for the H2B C-terminal helix in the trans-histone cross talk as a binding surface for Set1-COMPASS. We provide further insight into the trans-histone cross talk and propose that H2Bub1 stabilizes the nucleosome by preventing H2A-H2B eviction and, thereby, retains the "docking site" for Set1-COMPASS on chromatin to maintain its stable chromatin association, complex stability, and processive methylation.
Publication
Journal: Journal of Biological Chemistry
January/25/2010
Abstract
In Saccharomyces cerevisiae, lysine 4 on histone H3 (H3K4) is methylated by the Set1 complex (Set1C or COMPASS). Besides the catalytic Set1 subunit, several proteins that form the Set1C (Swd1, Swd2, Swd3, Spp1, Bre2, and Sdc1) are also needed to mediate proper H3K4 methylation. Until this study, it has been unclear how individual Set1C members interact and how this interaction may impact histone methylation and gene expression. In this study, Bre2 and Sdc1 are shown to directly interact, and it is shown that the association of this heteromeric complex is needed for proper H3K4 methylation and gene expression to occur. Interestingly, mutational and biochemical analysis identified the C terminus of Bre2 as a critical protein-protein interaction domain that binds to the Dpy-30 domain of Sdc1. Using the human homologs of Bre2 and Sdc1, ASH2L and DPY-30, respectively, we demonstrate that the C terminus of ASH2L also interacts with the Dpy-30 domain of DPY-30, suggesting that this protein-protein interaction is maintained from yeast to humans. Because of the functionally conserved nature of the C terminus of Bre2 and ASH2L, this region was named the SDI (Sdc1 Dpy-30 interaction) domain. Finally, we show that the SDI-Dpy-30 domain interaction is physiologically important for the function of Set1 in vivo, because specific disruption of this interaction prevents Bre2 and Sdc1 association with Set1, resulting in H3K4 methylation defects and decreases in gene expression. Overall, these and other mechanistic studies on how H3K4 methyltransferase complexes function will likely provide insights into how human MLL and SET1-like complexes or overexpression of ASH2L leads to oncogenesis.
Publication
Journal: Reproduction
June/18/2007
Abstract
Secreted phosphoprotein 1 (SPP1, osteopontin) is the most highly upregulated extracellular matrix/adhesion molecule/cytokine in the receptive phase human uterus, and Spp1 null mice manifest decreased pregnancy rates during mid-gestation as compared with wild-type counterparts. We hypothesize that Spp1 is required for proliferation, migration, survival, adhesion, and remodeling of cells at the conceptus-maternal interface. Our objective was to define the temporal/spatial distribution and steroid regulation of Spp1 in mouse uterus during estrous cycle and early gestation. In situ hybridization localized Spp1 to luminal epithelium (LE) and immune cells. LE expression was prominent at proestrus, decreased by estrus, and was nearly undetectable at diestrus. During pregnancy, Spp1 mRNA was not detected in LE until day 4.5 (day 1 = vaginal plug). Spp1-expressing immune cells were scattered within the endometrial stroma throughout the estrous cycle and early pregnancy. Immunoreactive Spp1 was prominent at the apical LE surface by day 4.5 of pregnancy and Spp1 protein was also co-localized with subsets of CD45-positive (leukocytes) and F4/80-positive (macrophages) cells. In ovariectomized mice, estrogen, but not progesterone, induced Spp1 mRNA, whereas estrogen plus progesterone did not induce Spp1 in LE. These results establish that estrogen regulates Spp1 in mouse LE and are the first to identify macrophages that produce Spp1 within the peri-implantation endometrium of any species. We suggest that Spp1 at the apical surface of LE provides a mechanism to bridge conceptus to LE during implantation, and that Spp1-positive macrophages within the stroma may be involved in uterine remodeling for conceptus invasion.
Publication
Journal: Development (Cambridge)
November/21/2011
Abstract
The atrioventricular canal (AVC) physically separates the atrial and ventricular chambers of the heart and plays a crucial role in the development of the valves and septa. Defects in AVC development result in aberrant heart morphogenesis and are a significant cause of congenital heart malformations. We have used a forward genetic screen in zebrafish to identify novel regulators of cardiac morphogenesis. We isolated a mutant, named wickham (wkm), that was indistinguishable from siblings at the linear heart tube stage but exhibited a specific loss of cardiac looping at later developmental stages. Positional cloning revealed that the wkm locus encodes transmembrane protein 2 (Tmem2), a single-pass transmembrane protein of previously unknown function. Expression analysis demonstrated myocardial and endocardial expression of tmem2 in zebrafish and conserved expression in the endocardium of mouse embryos. Detailed phenotypic analysis of the wkm mutant identified an expansion of expression of known myocardial and endocardial AVC markers, including bmp4 and has2. By contrast, a reduction in the expression of spp1, a marker of the maturing valvular primordia, was observed, suggesting that an expansion of immature AVC is detrimental to later valve maturation. Finally, we show that immature AVC expansion in wkm mutants is rescued by depleting Bmp4, indicating that Tmem2 restricts bmp4 expression to delimit the AVC primordium during cardiac development.
Publication
Journal: Physiological Genomics
January/30/2014
Abstract
We adopted a transcriptome-wide microarray analysis approach to determine the extent to which vascular gene expression is altered as a result of juvenile obesity and identify obesity-responsive mRNAs. We examined transcriptional profiles in the left anterior descending coronary artery (LAD), perivascular fat adjacent to the LAD, and descending thoracic aorta between obese (n = 5) and lean (n = 6) juvenile Ossabaw pigs (age = 22 wk). Obesity was experimentally induced by feeding the animals a high-fat/high-fructose corn syrup/high-cholesterol diet for 16 wk. We found that expression of 189 vascular cell genes in the LAD and expression of 165 genes in the thoracic aorta were altered with juvenile obesity (false discovery rate ≤ 10%) with an overlap of only 28 genes between both arteries. Notably, a number of genes found to be markedly upregulated in the LAD of obese pigs are implicated in atherosclerosis, including ACP5, LYZ, CXCL14, APOE, PLA2G7, LGALS3, SPP1, ITGB2, CYBB, and P2RY12. Furthermore, pathway analysis revealed the induction of proinflammatory and pro-oxidant pathways with obesity primarily in the LAD. Gene expression in the LAD perivascular fat was minimally altered with juvenile obesity. Together, we provide new evidence that obesity produces artery-specific changes in pretranslational regulation with a clear upregulation of proatherogenic genes in the LAD. Our data may offer potential viable drug targets and mechanistic insights regarding the molecular precursors involved in the origins of overnutrition and obesity-associated vascular disease. In particular, our results suggest that the oxidized LDL/LOX-1/NF-κB signaling axis may be involved in the early initiation of a juvenile obesity-induced proatherogenic coronary artery phenotype.
Publication
Journal: Oncogene
August/29/2017
Abstract
Tumour tissue is infiltrated by myeloid cells that are reprogrammed into alternatively activated/regenerative (M2) macrophages. The contribution of major signalling pathways and their modulators/targets involved in the macrophage reprogramming is poorly known. Glioblastoma (malignant brain tumour) attracts and reprograms brain-resident microglia and peripheral macrophages into cells that increase invasion, angiogenesis and suppress antitumour immunity. Using a 'function-first' approach and glioma secretome proteomics we identified osteopontin and lactadherin as proteins that cooperatively activate amoeboid transformation, phagocytosis and motility of primary microglia cultures via integrins and FAK-Akt (focal adhesion kinase-Akt) signalling. A synthetic peptide interfering with integrin ligands blocks glioma-microglia communication, functional activation and M2 gene expression. We found that osteopontin/secreted phosphoprotein 1 (Spp1) produced by non-transformed cells acts as a proinflammatory factor inducing inflammatory signalling and M1 genes, and counteracts the action of lactadherin. Using constructs encoding functional mutants of osteopontin, we demonstrated sequential processing of Spp1 by thrombin and matrix metalloproteinase-3 and/or -7 (MMP-3 and/or -7) in glioma cells, which generates a microglia-activating form devoid of the inflammatory activity, while retaining the M2 reprogramming potential. A similar form of osteopontin is secreted by human glioma cells but not normal human astrocytes. Knockdown of osteopontin or lactadherin in glioma cells reduces intracranial glioma growth, blocks amoeboid transformation of myeloid cells and affects M2 reprogramming of microglia/macrophages. Our findings demonstrate how glioma cells misuse macrophage-activating signals and redesign primarily proinflammatory signals towards their advantage to induce M2 reprogramming of tumour-infiltrating brain macrophages.
Publication
Journal: Journal of Hypertension
January/12/2005
Abstract
OBJECTIVE
We performed association studies between 118 single-nucleotide polymorphisms (SNPs) of 22 candidate genes (or gene family) and hypertension in a Japanese population.
METHODS
The study population consisted of 1880 subjects representing the general population in Japan, recruited from the Suita study. The candidate genes were selected based on their functions, including insulin resistance (APM1, CD36, HSD11B1), oxidative stress (CYBA, GPX1, GSTMs), steroid hormone (ESR1, ESR2, HSD11B2), renal functions (PTGS2, KLK1, NPHS1, NPHS2, SGK, SLC12A1, PTGES), and others related to cardiovascular physiology (GJA4, NOS1, NTRK3, P2RX4, SPP1, ALDH2).
RESULTS
Multiple logistic analyses, with age and body mass index as covariates, indicated that 13 SNPs (eight genes), six SNPs (four genes) and 11 SNPs (four genes) were associated with hypertension (P < 0.05) in the total, male, and female populations, respectively. PTGS2 seems to be a promising candidate gene for hypertension in men. GSTM3 and SLC12A1 seem to be promising candidate genes for hypertension in women. Especially, a polymorphism in SLC12A1 was significantly associated with hypertension in women even after correction by the Bonferroni method (corrected P = 0.0236). Multiple logistic analyses, with age and body mass index as covariates, indicated that the prevalence of hypertension in females was significantly higher in subjects with the CC genotype than in those with the TT + TC genotypes (P < 0.0001, odds ratio = 1.967, 95% confidence interval = 1.430-2.712).
CONCLUSIONS
Although the present results should be replicated in other study populations for confirmation, the present results suggest that SLC12A1 may contribute to hypertension in Japanese women.
Publication
Journal: Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie
June/12/2017
Abstract
OBJECTIVE
Tumor metastasis is still a great challenge for the prognosis of colorectal cancer (CRC). Although secreted phosphoprotein 1 (SPP1) over-expression is confirmed to associate with invasion, metastasis of CRC, the underlying mechanism by which modulates the CRC metastasis is still not fully explained.
METHODS
GDS4382 was obtained from GEO database and differentially expressed genes (DEGs) were analyzed by bioinformatics methods 55 paired samples of CRC and adjacent non-cancerous tissues were collected to detect the expression of SPP1 by q-PCR and western blot. Functional analysis of siRNA-SPP1, including proliferation, apoptosis, colony formation, cell cycle, migration, was investigated in CRC cell lines and tumor xenografts were conducted in nude mice. Protein expression of E-cadherin and vimentin was detected by western blot.
RESULTS
1887 DEGs were analyzed and selected from GDS4382, of which, SPP1 and epithelial-mesenchymal-transition (EMT) showed a close association by bioinformatics analysis. The mRNA and protein expression of SPP1 were significantly higher in CRC tissues than that in adjacent non-cancerous tissues (P<0.05). Overexpression of SPP1 closely associated with tumor invasion, metastasis and low survival in CRC. Moreover, siRNA-SPP1 repressed proliferation, cell cycle, colony formation, migration and tumor growth in vivo and promoted cell apoptosis in CRC cell lines. In addition, Protein expression of E-cadherin was obviously up-regulated and Vimentin was down-regulated in CRC cells after siRNA-SPP1 (P<0.05).
CONCLUSIONS
SPP1 expression was significantly up-regulated in CRC. And SPP1 promoted the metastasis of CRC by activating EMT, which could be a potentially therapeutic target for patients with CRC.
Publication
Journal: Arthritis
February/27/2014
Abstract
This review summarizes the genetic alterations and knockdown approaches published in the literature to assess the role of key proteoglycans and glycoproteins in the structural development, function, and repair of tendon, ligament, and enthesis. The information was collected from (i) genetically altered mice, (ii) in vitro knockdown studies, (iii) genetic variants predisposition to injury, and (iv) human genetic diseases. The genes reviewed are for small leucine-rich proteoglycans (lumican, fibromodulin, biglycan, decorin, and asporin); dermatan sulfate epimerase (Dse) that alters structure of glycosaminoglycan and hence the function of small leucine-rich proteoglycans by converting glucuronic to iduronic acid; matricellular proteins (thrombospondin 2, secreted phosphoprotein 1 (Spp1), secreted protein acidic and rich in cysteine (Sparc), periostin, and tenascin X) including human tenascin C variants; and others, such as tenomodulin, leukocyte cell derived chemotaxin 1 (chondromodulin-I, ChM-I), CD44 antigen (Cd44), lubricin (Prg4), and aggrecan degrading gene, a disintegrin-like and metallopeptidase (reprolysin type) with thrombospondin type 1 motif, 5 (Adamts5). Understanding these genes represents drug targets for disrupting pathological mechanisms that lead to tendinopathy, ligamentopathy, enthesopathy, enthesitis and tendon/ligament injury, that is, osteoarthritis and ankylosing spondylitis.
Publication
Journal: Journal of Structural Biology
April/18/2007
Abstract
The success of electron-cryo microscopy (cryo-EM) and image reconstruction of cyclic oligomers, such as the viral and bacteriophage portals, depends on the accurate knowledge of their order of symmetry. A number of statistical methods of image analysis address this problem, but often do not provide unambiguous results. Direct measurement of the oligomeric state of multisubunit protein assemblies is difficult when the number of subunits is large and one subunit renders only a small increment to the full size of the oligomer. Moreover, when mixtures of different stochiometries are present techniques such as analytical centrifugation or size-exclusion chromatography are also less helpful. Here, we use electrospray ionization mass spectrometry to directly determine the oligomeric states of the in vitro assembled portal oligomers of the phages P22, Phi-29 and SPP1, which range in mass from 430 kDa to about 1 million Da. Our data unambiguously reveal that the oligomeric states of Phi-29 and SPP1 portals were 12 and 13, respectively, in good agreement with crystallographic and electron microscopy data. However, in vitro assembled P22 portals were a mixture of 11- and 12-mer species in an approximate ratio of 2:1, respectively. A subsequent reference-free alignment of electron microscopy images of the P22 portal confirmed this mixture of oligomeric states. We conclude that macromolecular mass spectrometry is a valuable tool in structural biology that can aide in the determination of oligomeric states and symmetry of assemblies, providing a good starting point for improved image analysis of cryo-EM data.
Publication
Journal: Molecular & general genetics : MGG
March/30/1977
Abstract
Phage SPP1 infecting a mutator strain of B. subtilis (BD337) which carries a defective DNA polymerase III is mutagenized. This effect is absent in phages SPO2, SP82G and øe. The results confirm previous observations that SPP1 uses host DNA polymerase III for its DNA synthesis.
Publication
Journal: Journal of Virology
November/18/1972
Abstract
The role of the host polymerase in Bacillus subtilis infected with phage SPP1 was studied in vivo with regard to production of phage-specific and host-specific ribonucleic acid (RNA) and to phage yield. Evidence is presented that the subunit(s) of B. subtilis RNA polymerase which is sensitive to rifampin and streptolydigin is necessary at all times during infection for phage production. The synthesis of phage RNA and the phage yield in strains resistant to either antibiotic were unaffected by the drug. Host RNA synthesis continued throughout infection; phage-specific RNA never accounted for more than 20% of pulse-labeled RNA at any time during infection.
Publication
Journal: Journal of Anatomy
August/1/2004
Abstract
Alx4 and Msx2 encode homeodomain-containing transcription factors that show a clear functional overlap. In both mice and humans, loss of function of either gene is associated with ossification defects of the skull vault, although the major effect is on the frontal bones in mice and the parietal bones in humans. This study was undertaken to discover whether Alx4 and Msx2 show a genetic interaction in skull vault ossification, and to test the hypothesis that they interact with the pathway that includes the Fgfr genes, Twist1 and Runx2. We generated Alx4(+/-)/Msx2(+/-) double heterozygous mutant mice, interbred them to produce compound genotypes and analysed the genotype-phenotype relationships. Loss of an increasing number of alleles correlated with an incremental exacerbation of the skull vault defect; loss of Alx4 function had a marginally greater effect than loss of Msx2 and also affected skull thickness. In situ hybridization showed that Alx4 and Msx2 are expressed in the cranial skeletogenic mesenchyme and in the growing calvarial bones. Studies of the coronal suture region at embryonic day (E)16.5 revealed that Alx4 expression was decreased, but not abolished, in Msx2(-/-) mutants, and vice versa; expression of Fgfr2 and Fgfr1, but not Twist1, was reduced in both mutants at the same stage. Runx2 expression was unaffected in the coronal suture; in contrast, expression of the downstream ossification marker Spp1 was delayed. Double homozygous pups showed substantial reduction of alkaline phosphatase expression throughout the mineralized skull vault; they died at birth due to defects of the heart, lungs and diaphragm not previously associated with Alx4 or Msx2. Our observations suggest that Alx4 and Msx2 are partially functionally redundant, acting within a network of transcription factors and signalling events that regulate the rate of osteogenic proliferation and differentiation at a stage after the commitment of mesenchymal stem cells to osteogenesis.
Publication
Journal: Microbiology
January/15/1996
Abstract
An 837 nt long group IA intron was discovered in the Lactobacillus delbrueckii subsp. lactis virulent phage LL-H genome. The LL-H intron conforms well to the secondary structure that is common to all group I introns. The only exception is that the extreme 3' nucleotide of the intron is an A residue instead of the usual G; despite this the intron is efficiently spliced in vivo. This LL-H intron contains an ORF, ORF168, which shows homology with endonucleases encoded by ORFs contained in Bacillus subtilis phage introns. At present, the LL-H intron is the only one found in the phages of lactic acid bacteria and the first one to be found in a phage belonging to the most abundant taxonomic group, group B or Siphoviridae. The LL-H intron interrupts gene terL, the product of which (50.5 kDa, TerL) is significantly homologous to the large subunit of B. subtilis phage SPP1 terminase. The product of the upstream gene, terS of LL-H (15.9 kDa, TerS), shows homology to small subunits of B. subtilis phage terminases.
Publication
Journal: Molecular Cancer Therapeutics
October/14/2007
Abstract
Tumor cells are efficiently killed after incubation with alpha-emitter immunoconjugates targeting tumor-specific antigens. Therefore, application of alpha-emitter immunoconjugates is a promising therapeutic option for treatment of carcinomas that are characterized by dissemination of single tumor cells in the peritoneum like ovarian cancer or gastric cancer. In diffuse-type gastric cancer, 10% of patients express mutant d9-E-cadherin on the surface of tumor cells that is targeted by the monoclonal antibody d9MAb. Coupling of the alpha-emitter (213)Bi to d9MAb provides an efficient tool to eliminate HSC45-M2 gastric cancer cells expressing d9-E-cadherin in vitro and in vivo. Elucidation of the molecular mechanisms triggered by alpha-emitters in tumor cells could help to improve strategies of alpha-emitter radioimmunotherapy. For that purpose, gene expression of (213)Bi-treated tumor cells was quantified using a real time quantitative-PCR low-density array covering 380 genes in combination with analysis of cell proliferation and the mode of cell death. We could show that (213)Bi-induced cell death was initiated by G(2) arrest; up-regulation of tumor necrosis factor (TNF), SPHK1, STAT5A, p21, MYT1, and SSTR3; and down-regulation of SPP1, CDC25 phosphatases, and of genes involved in chromosome segregation. Together with morphologic changes, these results suggest that (213)Bi activates death cascades different from apoptosis. Furthermore, (213)Bi-triggered up-regulation of SSTR3 could be exploited for improvement of the therapeutic regimen.
Publication
Journal: Journal of Virology
January/18/1983
Abstract
The virulent Bacillus subtilis phage SPP1 transduces plasmid DNA. Plasmid-transducing phages contain only plasmid DNA. Such DNA represents a concatemer of monomeric plasmid molecules with the molecular weight of mature SPP1 DNA. Biological parameters of plasmid transduction are described.
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