990 resultados para Comparative Genomic Hybridization,


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The main objective of this work was to investigate the impact of different hybridization concepts and levels of hybridization on fuel economy of a standard road vehicle where both conventional and non-conventional hybrid architectures are treated exactly in the same way from the point of view of overall energy flow optimization. Hybrid component models were developed and presented in detail as well as the simulations results mainly for NEDC cycle. The analysis was performed on four different parallel hybrid powertrain concepts: Hybrid Electric Vehicle (HEV), High Speed Flywheel Hybrid Vehicle (HSF-HV), Hydraulic Hybrid Vehicle (HHV) and Pneumatic Hybrid Vehicle (PHV). In order to perform equitable analysis of different hybrid systems, comparison was performed also on the basis of the same usable system energy storage capacity (i.e. 625kJ for HEV, HSF and the HHV) but in the case of pneumatic hybrid systems maximal storage capacity was limited by the size of the systems in order to comply with the packaging requirements of the vehicle. The simulations were performed within the IAV Gmbh - VeLoDyn software simulator based on Matlab / Simulink software package. Advanced cycle independent control strategy (ECMS) was implemented into the hybrid supervisory control unit in order to solve power management problem for all hybrid powertrain solutions. In order to maintain State of Charge within desired boundaries during different cycles and to facilitate easy implementation and recalibration of the control strategy for very different hybrid systems, Charge Sustaining Algorithm was added into the ECMS framework. Also, a Variable Shift Pattern VSP-ECMS algorithm was proposed as an extension of ECMS capabilities so as to include gear selection into the determination of minimal (energy) cost function of the hybrid system. Further, cycle-based energetic analysis was performed in all the simulated cases, and the results have been reported in the corresponding chapters.

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CYP3A verstoffwechselt mehr als 50% aller gegenwärtig in der Therapie eingesetzten Wirkstoffe, die häufig an klinisch relevanten Arzneimitttel-Wechselwirkungen beteiligt sind. Das Verständnis über die Bedeutung und die Regulation von einzelnen CYP3A Genen in der Pharmakologie und Physiologie ist unvollständig. Wir untersuchten die Evolution des CYP3 Genlokus über einen Zeitraum von 450 Millionen Jahre mittels genomischer Sequenzen von 16 Tierarten. Neue CYP3 Unterfamilien (CYP3B, C und D) entstanden über eine beschleunigte Evolution aus CYP3A Vorstufen von Clupeocephala Spezies. Ausgeprägte funktionelle Unterschiede traten zwischen CYP3A in Säugern und Clupeocephala CYP3 auf. Alle amnioten CYP3A Gene entwickelten sich aus zwei CYP3A Urgenen. Aufgrund der Entstehung von Säugern mit Plazenta ging eines von ihnen verloren während das andere eine neue genomische Umgebung infolge einer Translokation erlangte. In Primaten unterzog sich CYP3A mit mehreren Genduplikationen, Deletionen, Pseudogenisierung und Genkonversionen einer raschen evolutionären Veränderung. Die Entwicklung von CYP3A in Schmalnasenaffen (Alte Welt Affen, große Menschenaffen und Menschen) unterschieden sich wesentlich von Neue Welt Primaten (z.B. gewöhnlichen Krallenaffen) und Feuchtnasenaffen (z.B. Galago). Stellvertretend für die CYP3A Protein-codierende Sequenz entdeckten wir zwei frühe Episoden von besonders starker positiver Selektion: (1) auf CYP3A7 in der frühen hominoiden Evolution, welche im fetalen Zeitraum von einer Einschränkung der hepatischen Expression begleitet war, und (2) auf humanes CYP3A4 im Anschluss an die Teilung der Abstammungslinie in Schimpansen und Mensch. In Übereinstimmung mit diesen Befunden beeinflussen drei von vier positiv ausgewählten Aminosäuren, die in früheren biochemischen CYP3A Studien untersucht wurden, die Aktivität und Regioselektivität. Es ist somit naheliegend, dass CYP3A7 und CYP3A4 katalytische Funktionen erworben haben können, die besonders wichtig waren für die Evolution von Hominoiden und Menschen. Die Charakterisierung von CYP3A Promotoren in Primaten zeigte eine Anreicherung von ER6 Elementen in CYP3A Promotoren von Primaten und einen Trend in Richtung Erhöhung der ER6 Enstehung entlang den Abstammungslinien, die zu humanen und Schimpansen CYP3A4 führten. Die steigende Anzahl an ER6 Elementen kann durch die ausgeprägte CYP3A4 Induzierbarkeit und Expressionsvariabilität im Menschen verursacht sein.

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Welche genetische Unterschiede machen uns verschieden von unseren nächsten Verwandten, den Schimpansen, und andererseits so ähnlich zu den Schimpansen? Was wir untersuchen und auch verstehen wollen, ist die komplexe Beziehung zwischen den multiplen genetischen und epigenetischen Unterschieden, deren Interaktion mit diversen Umwelt- und Kulturfaktoren in den beobachteten phänotypischen Unterschieden resultieren. Um aufzuklären, ob chromosomale Rearrangements zur Divergenz zwischen Mensch und Schimpanse beigetragen haben und welche selektiven Kräfte ihre Evolution geprägt haben, habe ich die kodierenden Sequenzen von 2 Mb umfassenden, die perizentrischen Inversionsbruchpunkte flankierenden Regionen auf den Chromosomen 1, 4, 5, 9, 12, 17 und 18 untersucht. Als Kontrolle dienten dabei 4 Mb umfassende kollineare Regionen auf den rearrangierten Chromosomen, welche mindestens 10 Mb von den Bruchpunktregionen entfernt lagen. Dabei konnte ich in den Bruchpunkten flankierenden Regionen im Vergleich zu den Kontrollregionen keine höhere Proteinevolutionsrate feststellen. Meine Ergebnisse unterstützen nicht die chromosomale Speziationshypothese für Mensch und Schimpanse, da der Anteil der positiv selektierten Gene (5,1% in den Bruchpunkten flankierenden Regionen und 7% in den Kontrollregionen) in beiden Regionen ähnlich war. Durch den Vergleich der Anzahl der positiv und negativ selektierten Gene per Chromosom konnte ich feststellen, dass Chromosom 9 die meisten und Chromosom 5 die wenigsten positiv selektierten Gene in den Bruchpunkt flankierenden Regionen und Kontrollregionen enthalten. Die Anzahl der negativ selektierten Gene (68) war dabei viel höher als die Anzahl der positiv selektierten Gene (17). Eine bioinformatische Analyse von publizierten Microarray-Expressionsdaten (Affymetrix Chip U95 und U133v2) ergab 31 Gene, die zwischen Mensch und Schimpanse differentiell exprimiert sind. Durch Untersuchung des dN/dS-Verhältnisses dieser 31 Gene konnte ich 7 Gene als negativ selektiert und nur 1 Gen als positiv selektiert identifizieren. Dieser Befund steht im Einklang mit dem Konzept, dass Genexpressionslevel unter stabilisierender Selektion evolvieren. Die meisten positiv selektierten Gene spielen überdies eine Rolle bei der Fortpflanzung. Viele dieser Speziesunterschiede resultieren eher aus Änderungen in der Genregulation als aus strukturellen Änderungen der Genprodukte. Man nimmt an, dass die meisten Unterschiede in der Genregulation sich auf transkriptioneller Ebene manifestieren. Im Rahmen dieser Arbeit wurden die Unterschiede in der DNA-Methylierung zwischen Mensch und Schimpanse untersucht. Dazu wurden die Methylierungsmuster der Promotor-CpG-Inseln von 12 Genen im Cortex von Menschen und Schimpansen mittels klassischer Bisulfit-Sequenzierung und Bisulfit-Pyrosequenzierung analysiert. Die Kandidatengene wurden wegen ihrer differentiellen Expressionsmuster zwischen Mensch und Schimpanse sowie wegen Ihrer Assoziation mit menschlichen Krankheiten oder dem genomischen Imprinting ausgewählt. Mit Ausnahme einiger individueller Positionen zeigte die Mehrzahl der analysierten Gene keine hohe intra- oder interspezifische Variation der DNA-Methylierung zwischen den beiden Spezies. Nur bei einem Gen, CCRK, waren deutliche intraspezifische und interspezifische Unterschiede im Grad der DNA-Methylierung festzustellen. Die differentiell methylierten CpG-Positionen lagen innerhalb eines repetitiven Alu-Sg1-Elements. Die Untersuchung des CCRK-Gens liefert eine umfassende Analyse der intra- und interspezifischen Variabilität der DNA-Methylierung einer Alu-Insertion in eine regulatorische Region. Die beobachteten Speziesunterschiede deuten darauf hin, dass die Methylierungsmuster des CCRK-Gens wahrscheinlich in Adaption an spezifische Anforderungen zur Feinabstimmung der CCRK-Regulation unter positiver Selektion evolvieren. Der Promotor des CCRK-Gens ist anfällig für epigenetische Modifikationen durch DNA-Methylierung, welche zu komplexen Transkriptionsmustern führen können. Durch ihre genomische Mobilität, ihren hohen CpG-Anteil und ihren Einfluss auf die Genexpression sind Alu-Insertionen exzellente Kandidaten für die Förderung von Veränderungen während der Entwicklungsregulation von Primatengenen. Der Vergleich der intra- und interspezifischen Methylierung von spezifischen Alu-Insertionen in anderen Genen und Geweben stellt eine erfolgversprechende Strategie dar.

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The three-spined stickleback is a widespread Holarctic species complex that radiated from the sea into freshwaters after the retreat of the Pleistocene ice sheets. In Switzerland, sticklebacks were absent with the exception of the far northwest, but different introduced populations have expanded to occupy a wide range of habitats since the late 19th century. A well-studied adaptive phenotypic trait in sticklebacks is the number of lateral plates. With few exceptions, freshwater and marine populations in Europe are fixed for either the low plated phenotype or the fully plated phenotype, respectively. Switzerland, in contrast, harbours in close proximity the full range of phenotypic variation known from across the continent. We addressed the phylogeographic origins of Swiss sticklebacks using mitochondrial partial cytochrome b and control region sequences. We found only five different haplotypes but these originated from three distinct European regions, fixed for different plate phenotypes. These lineages occur largely in isolation at opposite ends of Switzerland, but co-occur in a large central part. Across the country, we found a strong correlation between a microsatellite linked to the high plate ectodysplasin allele and the mitochondrial haplotype from a region where the fully plated phenotype is fixed. Phylogenomic and population genomic analysis of 481 polymorphic amplified fragment length polymorphism loci indicate genetic admixture in the central part of the country. The same part of the country also carries elevated within-population phenotypic variation. We conclude that during the recent invasive range expansion of sticklebacks in Switzerland, adaptive and neutral between-population genetic variation was converted into within-population variation, raising the possibility that hybridization between colonizing lineages contributed to the ecological success of sticklebacks in Switzerland.

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Cytochrome P450 enzymes (CYP450s) represent a superfamily of haem-thiolate proteins. CYP450s are most abundant in the liver, a major site of drug metabolism, and play key roles in the metabolism of a variety of substrates, including drugs and environmental contaminants. Interaction of two or more different drugs with the same enzyme can account for adverse effects and failure of therapy. Human CYP3A4 metabolizes about 50% of all known drugs, but little is known about the orthologous CYP450s in horses. We report here the genomic organization of the equine CYP3A gene cluster as well as a comparative analysis with the human CYP3A gene cluster. The equine CYP450 genes of the 3A family are located on ECA 13 between 6.97-7.53 Mb, in a region syntenic to HSA 7 99.05-99.35 Mb. Seven potential, closely linked equine CYP3A genes were found, in contrast to only four genes in the human genome. RNA was isolated from an equine liver sample, and the approximately 1.5-kb coding sequence of six CYP3A genes could be amplified by RT-PCR. Sequencing of the RT-PCR products revealed numerous hitherto unknown single nucleotide polymorphisms (SNPs) in these six CYP3A genes, and one 6-bp deletion compared to the reference sequence (EquCab2.0). The presence of the variants was confirmed in a sample of genomic DNA from the same horse. In conclusion, orthologous genes for the CYP3A family exist in horses, but their number differs from those of the human CYP3A gene family. CYP450 genes of the same family show high homology within and between mammalian species, but can be highly polymorphic.

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Background: The bacterial colonization of the oral mucosa was evaluated in patients with asymptomatic oral lichen planus (OLP) and compared to the microbiologic status in mucosally healthy subjects. Methods: Bacteria from patients with clinically and histopathologically diagnosed OLP from the Stomatology Service, Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, were collected with a non-invasive swab system. Samples were taken from OLP lesions on the gingiva and from non-affected sites on the contralateral side of the mouth. The control population did not have OLP and was recruited from the student clinic. All samples were processed with the checkerboard DNA-DNA hybridization method using well-defined bacterial species for the analysis. Results: Significantly higher bacterial counts of Bacteroides ureolyticus (P = 0.001), Dialister species (sp.) (P = 0.006), Staphylococcus haemolyticus (P = 0.007), and Streptococcus agalactiae (P = 0.006) were found in samples taken from OLP lesions compared to sites with no clinical evidence of OLP. Significantly higher bacterial counts were found for Capnocytophaga sputigena, Eikenella corrodens, Lactobacillus crispatus, Mobiluncus curtisii, Neisseria mucosa, Prevotella bivia, Prevotella intermedia, and S. agalactiae at sites with lesions in subjects with OLP compared to sites in control subjects (P <0.001). Conclusions: Microbiologic differences were found between sites with OLP and sites in subjects without a diagnosis of OLP. Specifically, higher counts of staphylococci and S. agalactiae were found in OLP lesions.

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BACKGROUND: As for Cystic Fibrosis (CF) and many other hereditary diseases there is still a lack in understanding the relationship between genetic (e.g. allelic) and phenotypic diversity. Therefore methods which allow fine quantification of allelic proportions of mRNA transcripts are of high importance. METHODS: We used either genomic DNA (gDNA) or total RNA extracted from nasal cells as starting nucleic acid template for our assay. The subjects included in this study were 9 CF patients compound heterozygous for the F508del mutation and each one F508del homozygous and one wild type homozygous respectively. We established a novel ligation based quantification method which allows fine quantification of the allelic proportions of ss and ds CFTR cDNA. To verify reliability and accuracy of this novel assay we compared it with semiquantitative fluorescent PCR (SQF-PCR). RESULTS: We established a novel assay for allele specific quantification of gene expression which combines the benefits of the specificity of the ligation reaction and the accuracy of quantitative real-time PCR. The comparison with SQF-PCR clearly demonstrates that LASQ allows fine quantification of allelic proportions. CONCLUSION: This assay represents an alternative to other fine quantitative methods such as ARMS PCR and Pyrosequencing.

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Hardwoods comprise about half of the biomass of forestlands in North America and present many uses including economic, ecological and aesthetic functions. Forest trees rely on the genetic variation within tree populations to overcome the many biotic, abiotic, anthropogenic factors which are further worsened by climate change, that threaten their continued survival and functionality. To harness these inherent genetic variations of tree populations, informed knowledge of the genomic resources and techniques, which are currently lacking or very limited, are imperative for forest managers. The current study therefore aimed to develop genomic microsatellite markers for the leguminous tree species, honey locust, Gleditsia triacanthos L. and test their applicability in assessing genetic variation, estimation of gene flow patterns and identification of a full-sib mapping population. We also aimed to test the usefulness of already developed nuclear and gene-based microsatellite markers in delineation of species and taxonomic relationships between four of the taxonomically difficult Section Lobatae species (Quercus coccinea, Q. ellipsoidalis, Q. rubra and Q. velutina. We recorded 100% amplification of G. triacanthos genomic microsatellites developed using Illumina sequencing techniques in a panel of seven unrelated individuals with 14 of these showing high polymorphism and reproducibility. When characterized in 36 natural population samples, we recorded 20 alleles per locus with no indication for null alleles at 13 of the 14 microsatellites. This is the first report of genomic microsatellites for this species. Honey locust trees occur in fragmented populations of abandoned farmlands and pastures and is described as essentially dioecious. Pollen dispersal if the main source of gene flow within and between populations with the ability to offset the effects of random genetic drift. Factors known to influence gene include fragmentation and degree of isolation, which make the patterns gene flow in fragmented populations of honey locust a necessity for their sustainable management. In this follow-up study, we used a subset of nine of the 14 developed gSSRs to estimate gene flow and identify a full-sib mapping population in two isolated fragments of honey locust. Our analyses indicated that the majority of the seedlings (65-100% - at both strict and relaxed assignment thresholds) were sired by pollen from outside the two fragment populations. Only one selfing event was recorded confirming the functional dioeciousness of honey locust and that the seed parents are almost completely outcrossed. From the Butternut Valley, TN population, pollen donor genotypes were reconstructed and used in paternity assignment analyses to identify a relatively large full-sib family comprised of 149 individuals, proving the usefulness of isolated forest fragments in identification of full-sib families. In the Ames Plantation stand, contemporary pollen dispersal followed a fat-tailed exponential-power distribution, an indication of effective gene flow. Our estimate of δ was 4,282.28 m, suggesting that insect pollinators of honey locust disperse pollen over very long distances. The high proportion of pollen influx into our sampled population implies that our fragment population forms part of a large effectively reproducing population. The high tendency of oak species to hybridize while still maintaining their species identity make it difficult to resolve their taxonomic relationships. Oaks of the section Lobatae are famous in this regard and remain unresolved at both morphological and genetic markers. We applied 28 microsatellite markers including outlier loci with potential roles in reproductive isolation and adaptive divergence between species to natural populations of four known interfertile red oaks, Q. coccinea, Q. ellpsoidalis, Q. rubra and Q. velutina. To better resolve the taxonomic relationships in this difficult clade, we assigned individual samples to species, identified hybrids and introgressive forms and reconstructed phylogenetic relationships among the four species after exclusion of genetically intermediate individuals. Genetic assignment analyses identified four distinct species clusters, with Q. rubra most differentiated from the three other species, but also with a comparatively large number of misclassified individuals (7.14%), hybrids (7.14%) and introgressive forms (18.83%) between Q. ellipsoidalis and Q. velutina. After the exclusion of genetically intermediate individuals, Q. ellipsoidalis grouped as sister species to the largely parapatric Q. coccinea with high bootstrap support (91 %). Genetically intermediate forms in a mixed species stand were located proximate to both potential parental species, which supports recent hybridization of Q. velutina with both Q. ellipsoidalis and Q. rubra. Analyses of genome-wide patterns of interspecific differentiation can provide a better understanding of speciation processes and taxonomic relationships in this taxonomically difficult group of red oak species.

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Unique and shared cytogenetic abnormalities have been documented for marginal zone lymphomas (MZLs) arising at different sites. Recently, homozygous deletions of the chromosomal band 6q23, involving the tumor necrosis factor alpha-induced protein 3 (TNFAIP3, A20) gene, a negative regulator of NF-kappaB, were described in ocular adnexal MZL, suggesting a role for A20 as a tumor suppressor in this disease. Here, we investigated inactivation of A20 by DNA mutations or deletions in a panel of extranodal MZL (EMZL), nodal MZL (NMZL), and splenic MZL (SMZL). Inactivating mutations encoding truncated A20 proteins were identified in 6 (19%) of 32 MZLs, including 2 (18%) of 11 EMZLs, 3 (33%) of 9 NMZLs, and 1 (8%) of 12 SMZLs. Two additional unmutated nonsplenic MZLs also showed monoallelic or biallelic A20 deletions by fluorescent in situ hybridization (FISH) and/or SNP-arrays. Thus, A20 inactivation by either somatic mutation and/or deletion represents a common genetic aberration across all MZL subtypes, which may contribute to lymphomagenesis by inducing constitutive NF-kappaB activation.

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Recent reports indicate that cytotoxic T cells are critically involved in contact hypersensitivity reactions in animals. In this study we sought to investigate the in vivo expression of cytotoxic granule proteins in the elicitation phase of allergic contact dermatitis in humans. Skin biopsy specimens were obtained from patients with allergic contact dermatitis (n = 8) and psoriasis (n = 6) and from controls with normal skin (n = 6). Expression of perforin and granzyme B was investigated by in situ hybridization and immunohistochemistry. In contrast to normal skin and psoriasis, a significant enhancement of perforin and granzyme B gene expression and immunoreactivity was observed in the mononuclear cell infiltrate of allergic contact dermatitis. Immunoreactivity for perforin and granzyme B was mainly found in the cytoplasm of lymphocytic cells, which were located in the dense perivascular infiltrate as well as at sites of marked spongiosis in the epidermis. Double immunostaining revealed that both CD4+ and CD8+ T cells are capable of expressing perforin and granzyme B. In conclusion, our data suggest that T-cell-mediated mechanisms involving cytotoxic granule proteins may elicit epidermal cell injury in vivo and thereby strongly contribute to the development of allergic contact dermatitis in humans.

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Background: Speciation reversal: the erosion of species differentiation via an increase in introgressive hybridization due to the weakening of previously divergent selection regimes, is thought to be an important, yet poorly understood, driver of biodiversity loss. Our study system, the Alpine whitefish (Coregonus spp.) species complex is a classic example of a recent postglacial adaptive radiation: forming an array of endemic lake flocks, with the independent origination of similar ecotypes among flocks. However, many of the lakes of the Alpine radiation have been seriously impacted by anthropogenic nutrient enrichment, resulting in a collapse in neutral genetic and phenotypic differentiation within the most polluted lakes. Here we investigate the effects of eutrophication on the selective forces that have shaped this radiation, using population genomics. We studied eight sympatric species assemblages belonging to five independent parallel adaptive radiations, and one species pair in secondary contact. We used AFLP markers, and applied FST outlier (BAYESCAN, DFDIST) and logistic regression analyses (MATSAM), to identify candidate regions for disruptive selection in the genome and their associations with adaptive traits within each lake flock. The number of outlier and adaptive trait associated loci identified per lake were then regressed against two variables (historical phosphorus concentration and contemporary oxygen concentration) representing the strength of eutrophication. Results: Whilst we identify disruptive selection candidate regions in all lake flocks, we find similar trends, across analysis methods, towards fewer disruptive selection candidate regions and fewer adaptive trait/candidate loci associations in the more polluted lakes. Conclusions: Weakened disruptive selection and a concomitant breakdown in reproductive isolating mechanisms in more polluted lakes has lead to increased gene flow between coexisting Alpine whitefish species. We hypothesize that the resulting higher rates of interspecific recombination reduce either the number or extent of genomic islands of divergence surrounding loci evolving under disruptive natural selection. This produces the negative trend seen in the number of selection candidate loci recovered during genome scans of whitefish species flocks, with increasing levels of anthropogenic eutrophication: as the likelihood decreases that AFLP restriction sites will fall within regions of heightened genomic divergence and therefore be classified as FST outlier loci. This study explores for the first time the potential effects of human-mediated relaxation of disruptive selection on heterogeneous genomic divergence between coexisting species.

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The Spec genes serve as molecular markers for examining the ontogeny of the aboral ectoderm lineage of sea urchin embryos. These genes are activated at late-cleavage stage only in cells contributing to the aboral ectoderm of Strongylocentrotus purpuratus and encode 14,000-17,000 Da calcium-binding proteins. A comparative analysis was undertaken to better understand the mechanisms underlying the activation and function of the Spec genes by investigating Spec homologues from Lytechinus pictus, a distantly related sea urchin. Spec antibodies cross-reacted with 34,000 Da proteins in L. pictus embryos that displayed a similar ontogenetic pattern to that of Spec proteins. One cDNA clone, LpS1, was isolated by hybridization to a synthetic oligonucleotide corresponding to a calcium-binding domain or EF-hand. The LpS1 mRNA has developmental properties similar to those of the Spec mRNAs. LpS1 encodes a 34,000 Da protein containing eight EF-hand domains, which share structural homology with the Spec EF-hands; however, little else in the protein sequence is conserved, implying that calcium-binding is important for Spec protein function. Genomic DNA blot analysis showed two LpS1 genes, LpS1$\alpha$ and LpS1$\beta$, in L. pictus. Partial gene structures for both LpS1$\alpha$ and $\beta$ were constructed based on genomic clones isolated from an L. pictus genomic library. These revealed internal duplications of the LpS1 genes that accounted for the eight EF-hand domains in the LpS1 proteins. Sequencing analysis showed there was little in common among the 5$\sp\prime$-flanking regions of the LpS1 and Spec genes except for the presence of a binding site for the transcription factor USF.^ A sea urchin gene-transfer expression system showed that 762 base pairs (bp) of 5$\sp\prime$-flanking DNA from the LpS1$\beta$ gene were sufficient for correct temporal and spatial expression of reporter genes in sea urchin embryos. Deletions at the 5$\sp\prime$ end to 511, 368, or 108bp resulted in a 3-4 fold decrease in chloramphenicol acetyltransferase (CAT) activity and disrupted the restricted activation of the lac Z gene in aboral ectoderm cells.^ A full-length Spec1 protein and a truncated LpS1 protein were induced and partially purified from an in vitro expression system. (Abstract shortened with permission of author.) ^

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Murine sarcoma viruses constitute a class of replication-defective retroviruses. Cellular transformation may be induced by these viruses in vitro; whereas, fibrosarcomas may result in animals infected with them in vivo (Tooze, 1973; Bishop, 1978). Hybridization studies suggest that murine sarcoma viruses arose by recombination between nondefective murine leukemia virus sequences and certain cellular sequences present in uninfected mouse cells (Hu et al., 1977). A specific gene product, however, has not been implicated in murine sarcoma virus transformation.^ One line of murine sarcoma virus-producing cells, Mo-MuSV-clone 124, (Ball et al., 1973), was studied biochemically because it mainly produces the sarcoma virus as a pseudotype packaged with helper murine leukemia virus proteins. The sarcoma viral RNA was translated in a sophisticated cell-free protein synthesizing system (Murphy and Arlinghaus, 1978). The translation products were analyzed by a number of techniques, including electrophoresis in denaturing gels of SDS polyacrylamide, immunoprecipitation, and peptide mapping. The major products of the total RNA purified from the virus preparation were shown to have molecular weights of about 63,000 (P63('gag)), 42,000 (P42), 40,000 (P40), 38,000 (P38), and 23,000 (P23). The size class of mRNA coding for each of the cell-free products was estimated using a poly(A) selection technique and sucrose gradient fractionation. These analyses were used to localize the coding information related to each of the in vitro synthesized cell-free products within the sarcoma virus genome.^ The major findings of these studies were: (1) the 5' half of the sarcoma viral RNA codes for the 63,000 dalton polypeptide and 42,000 - 38,000 dalton polypeptides derived from the "gag" gene; and (2) the 3' half of the sarcoma viral RNA codes for a 38,000 dalton polypeptide and possibly derived from the cellular acquired sequences. ^

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The loci of the porcine tumour necrosis factor genes, alpha (TNFA) and beta (TNFB), have been chromosomally assigned by radioactive in situ hybridization. The genomic probes for TNFA and TNFB yielded signals above 7p11-q11, a region that has been shown earlier to carry the porcine major histocompatibility locus (SLA). These mapping data along with preliminary molecular studies suggest a genomic organization of the SLA that is similar to that of human and murine major histocompatibility complexes.

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We have cloned and sequenced a 10.22-kb fragment of the genomic locus of the porcine tumor necrosis factor-encoding genes, TNF-alpha and TNF-beta. A liver genomic DNA library, partially digested with Sau3AI, was cloned into the phage lambda EMBL4 and screened with a porcine TNF-alpha cDNA probe. Analysis showed that both the TNF-alpha and TNF-beta genes were present on the cloned fragment. In addition, the cloned fragment contained about 2 kb of repetitive sequences 5' to the TNF-beta gene. The TNF genes are arranged in a tandem repeat, as is the case for the human, mouse and rabbit TNF genes. The comparison of both genes with their human homologues displayed a considerable degree of conservation (80%), suggesting an equal evolution rate.