Submitted by Cláudia Bueno (claudiamoura18@gmail.com) on 2016-04-05T19:37:55Z No. of bitstreams: 2 Dissertação - Fernanda Raquel Martins Abreu - 2014.pdf: 2480777 bytes, checksum: f8c50ff359945dffab56d7874ad25086 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-04-06T11:34:39Z (GMT) No. of bitstreams: 2 Dissertação - Fernanda Raquel Martins Abreu - 2014.pdf: 2480777 bytes, checksum: f8c50ff359945dffab56d7874ad25086 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-04-06T11:34:39Z (GMT). No. of bitstreams: 2 Dissertação - Fernanda Raquel Martins Abreu - 2014.pdf: 2480777 bytes, checksum: f8c50ff359945dffab56d7874ad25086 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-04-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Drought, a major problem concerning a sustainable rice production in Brazil and worldwide, is responsible for a series of plant responses, including modification in gene expression, accumulation of metabolites and protein synthesis. In order to verify the correspondence between five Arabidopsis genes (PLDα1, LEW2, GluR2, Lsi1 e EIN2), previously related to drought tolerance, and their respective orthologs in rice, the present study analyzed two contrasting rice genotypes for drought, Douradão, the tolerant genotype, and Primavera, the susceptible one. The genotypes were submitted to drought stress and subsequently evaluated for gene expression by quantitative real-time Polymerase Chain Reaction (qPCR). The comparison of gene expression, between leaf and root tissues, showed a greater expression in roots, within their vegetative stage, and leaves, within their reproductive stage. Differential expression were observed mainly among the genes whose orthologs in Arabidopsis encode phospholipase Dα1 (PLDα1) and ethylene-insensitive protein (EIN2); these proteins are directly related to abscisic acid (ABA), a phytohormone that when identified in higher concentration in cells triggers the expression of drought stress-responsive genes, besides it is also responsible for the regulating the water loss (by transpiration) by controlling of stomatal movement. The results suggested that orthologs genes were in fact drought stress-responsive genes in rice, and emphasized the feasibility of PLDα1 and EIN2 overexpression in rice plants, supporting plant breeding programs in the development of drought tolerant genotypes. / A seca, um dos principais problemas para a sustentabilidade do cultivo de arroz no Brasil e no mundo, é responsável por uma série de respostas em plantas, incluindo mudanças na expressão gênica, acúmulo de metabólitos e síntese de proteínas. No intuito de verificar a correspondência entre cinco genes de Arabidopsis (PLDα1, LEW2, GluR2, Lsi1 e EIN2), previamente relacionados com a tolerância à seca, e seus respectivos genes ortólogos em arroz, o presente estudo analisou dois genótipos de arroz contrastantes no nível de tolerância à seca, Douradão, genótipo tolerante, e Primavera, genótipo susceptível. Os genótipos foram submetidos a experimento de seca e posterior avaliação de expressão gênica via PCR quantitativa em tempo real, qPCR (real time quantitative-Polimerase Chain Reaction). Ao se comparar os níveis de expressão entre os tecidos foliar e radicular, desses genótipos, foi observado, de uma forma geral, que houve maior expressão em raízes no estádio vegetativo e em folhas no estádio reprodutivo. Níveis diferenciais de expressão entre os genótipos foram observados principalmente para os genes ortólogos responsáveis por produzir fosfolipase Dα1 (PLDα1) e proteína etileno insensitiva (EIN2); estes produtos estão diretamente relacionados ao ácido abscísico (ABA), um fito hormônio induzido por estresse de seca que, quando em alta concentração nas células, além de acionar a expressão de muitos genes, desempenha um papel vital na regulação da perda de água por transpiração ao controlar os movimentos estomáticos. Os resultados apresentados nesta pesquisa sugeriram que os genes ortólogos estariam de fato atuando em resposta à tolerância à seca em arroz, e reforçaram a hipótese de que a superexpressão desses genes, em especial, PLDα1 e EIN2, pode auxiliar programas de melhoramento genético de arroz no desenvolvimento de cultivares mais tolerantes à seca.

A pesquisa teve como objetivo avaliar a possibilidade de obtenção de segregantes transgressivos precoces e produtivos através de 12 cruzamentos envolvendo 6 parentais exóticos (Pella, Williams, Century, Maple Presto, Maple Amber e Maccall) com dois parentais adaptados (BR80-6989 e Primavera). Foram estudadas as 12 progênies F 2 em 12 experimentos delineados em blocos casualizados com quatro repetições. Foram avaliados os seguintes caracteres: número de dias para início de florescimento, número de dias para maturidade, altura da planta no florescimento, altura da planta na maturidade, acamamento, valor agronômico, produtividade de planta individual e produtividade de parcela. Os resultados permitiram as seguintes conclusões: a) os parentais possuem características complementares de interesse para o melhoramento; b) houve uma grande variação de heterose e heterobeltiose porém nem sempre as maiores médias estavam associadas as maiores variâncias; c) a avaliação das progênies F2 através da frequência de genótipos superiores, demonstrou a existência de segregantes transgressivos que reuniam simultaneamente a precocidade, altura adequada a colheita mecanizada e produtividade / This research aimed to evaluate the potential of crosses between exotic and adapted parents for development of transgressive segregates having high levels of earliness and seed yielding. Six exotics parents (Century, Maple Amber, Maple Presto, McCall, Pella and Williams) were chosen based on their earliness and seed yielding; such parents exhibited the disadvantage of to be very sensitives to photoperiodic variations. Two adapted parents (BR 80-6989 and Primavera) were chosen based on their small sensitivity to variation and high seed yielding. However, they exhibited lower earliness than necessary. In 1985, handled hibridizations were made to obtaining 12 crosses (six exotic x two adapted). Natural selfing originated the F 2, that were evaluated at 12 experiments establishe in randomized block design with four replications. The results allowed the following conclusions: a) the parents were significantly different them selves; consequently, complementary traits were combined in all crosses; b) a large heterosis and heterobeltiosis variation were found for all traits evaluated, however, the higher means were not always related to higher variances; c) the combination of high earliness from exotic parents with long-juvenile trait from adapted parents was a promissing strategy for development of transgressive segregates appropriated to rotation crop with sugarcane

Orientadores: Gonçalo Amarante Guimarães Pereira, Lyndel W. Meinhardt / Dissertção (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-03T19:36:10Z (GMT). No. of bitstreams: 1 Cotomacci_Carolina_M.pdf: 1686245 bytes, checksum: 0c1ced68745955b067ac66ec4f710046 (MD5) Previous issue date: 2004 / Resumo: A doença vassoura-de-bruxa em Theobroma cacao (cacaueiro), causada pelo fungo Crinipellis perniciosa, é uma das doenças de maior impacto econômico nos países produtores de cacau, sendo o Brasil um destes países. Esse fungo infecta os tecidos meristemáticos do cacaueiro em duas fases: parasítica e saprofítica. Pesquisas com outros fitopatógenos têm demonstrado que a mudança da fase parasítica para a saprofítica é regulada por genes do sistema mating type tornando este estudo extremamente importante para inferir estratégias de combate à doença. O presente trabalho teve por finalidade identificar os genes mating type de C. perniciosa através da análise dos dados gerados pelo seu projeto genoma. Para a identificação dos genes do sistema mating type (Hd1, Hd2, Rc e Fe) foram feitas buscas no banco de dados do genoma de C. perniciosa comparando seqüências similares àquelas codificadas pelos fungos basidiomicetos Coprinus cinereus, Coprinus bilanatus, Schizophyllum commune e Ustilago maydis, identificadas e disponibilizadas em rede. Foram identificados seis genes do sistema mating type de C. perniciosa. Um gene que codifica a proteína regulatória Hd1, um gene que codifica a proteína regulatória Hd2 e quatro genes que codificam as proteínas receptoras de ferormônio Rc1, Rc2, Rc3 e Rc4. Não foram identificados genes que codificam ferormônios. Portanto, concluímos que a organização molecular do sistema mating type de C. perniciosa é tetrapolar, contendo o locus HD bialélico e o locus FRF multialélico / Abstract: The witch's broom disease in Theobroma cacao, caused by mushroom Crinipellis perniciosa, is one of the diseases with the biggest economic impact in cocoa producing countries, and Brazil is one of them. The mushroom infects the meristematics tissues of the cocoa tree in two phases: parasitic and saprofitic. Research with other phytopathogens have demonstrated that the change from the parasitic to the saprophytic phase is regulated by genes of the mating type system, making this study extremely important to infer fighting strategies to this disease. This work's proposal is to identify mating type genes of C. perniciosa through the analysis of data generated by its genome project. The genes identification of the (Hd1, Hd2, Rc and Fe) mating type system was made by database search in the C. perniciosa genome comparing similar sequences with the ones codified by the basidiomycetes mushrooms Coprinus cinereus, Coprinus bilanatus, Schizophyllum commune and Ustilago maydis, identified and available in the internet. Six genes were identified in C. perniciosa mating type system. One gene that codifies the regulatory protein Hd1, another that codifies the regulatory protein Hd2 and four genes that codify the pheromone receptor proteins Rc1, Rc2, Rc3 and Rc4. Genes that codify pheromones were not identified. Therefore, we concluded that the molecular organization of C. perniciosa mating type system is tetrapolar, containing the bialelic HD locus and the multialelic FRF locus / Mestrado / Bioquimica / Mestre em Biologia Funcional e Molecular

Orientador: Pedro Duarte Novaes / Tese (doutorado) - Universidade Estadual de Campinas. Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-03T23:43:09Z (GMT). No. of bitstreams: 1 Peres_ReginaCeliaRocha_D.pdf: 6067359 bytes, checksum: a2d580a3899a06126039215c20821040 (MD5) Previous issue date: 2004 / Resumo: Hipodontia, a ausência congênita de um ou mais dentes, é uma das alterações mais comuns da dentição humana. Os dentes mais atingidos são os terceiros molares, segundos pré-molares superiores, e incisivos laterais superiores. Embora hipodontia não represente um sério problema de saúde pública, pode causar disfunção na mastigação e fala, além de problemas estéticos. Os genes TGFBETA1, MMP9, TIMP2 e PAX9 estão expressos em várias regiões do germe dentário durante as diversas fases da odontogênese. Estudos recentes mostram que polimorfismos em regiões reguladoras da transcrição parecem ser freqüentes, e que estas variações são responsáveis por características fenotípicas individuais. No entanto, pouco se sabe sobre o papel de polimorfismos genéticos no surgimento da agenesia dental de forma isolada. O objetivo do presente estudo foi analisar a associação existente entre os polimorfismos na região promotora dos genes TGF BETA1, MMP9, TIMP2 e PAX9, e a agenesia dental de terceiros molares, segundos pré-molares e incisivos laterais. A amostra foi composta pelo DNA genômico de 50 indivíduos afetados e 50 indivíduos controles, com idade acima de 16 anos, para os três primeiros marcadores. Com o objetivo de aumentar a amostra, a análise de polimorfismos no gene PAX9 foi realizada utilizando-se o DNA genômico de 100 indivíduos afetados e 100 indivíduos controles. Após a obtenção e extração do DNA, as regiões de interesse foram amplificadas por reação em cadeia da polimerase (PCR) e os polimorfismos foram analisados por digestão com enzima de restrição. Os géis foram corados pelo nitrato de prata. A análise estatística foi realizada através das Simulações de Monte Carlo (programa Clump) e teste Qui-quadrado ao nível de significância de 5%. O programa ARLEQUIN foi utilizado para verificar combinações de haplótipos nos genes do TGF- BETA1 e PAX9. As análises mostraram que o polimorfismo da região promotora do TIMP2 não está presente na população estudada, que os polimorfismos na região promotora dos genes TGF BETA1 e MMP9 não estão associados com agenesia dental, e que os polimorfismos no promotor do PAX9 estão associados com a agenesia dental, podendo ser considerados marcadores genéticos para a hipodontia / Abstract: Hypodontia, the congenital absence of one or a few teeth, is one of the most common alterations of the human dentition. The most common permanent missing teeth are the third molars, maxillary second premolars and maxillary lateral incisors. Although hypodontia does not represent a serious public health problem, it may cause masticatory and speech dysfunctions and esthetic problems. TGFBETA1, MMP9, TIMP2 and PAX9 genes are expressed in many regions of the tooth germ during the diverse phases of odontogenesis. Recent studies show that polymorphisms in transcription regulator regions seem to be frequent and that these variations are responsible for individual phenotypic features. However, the role of genetic polymorphisms in the development of sporadic tooth agenesis is not established. The aim of this study was to analyse the association between TGF BETA1, MMP9, TIMP2 and PAX9 genes promoter polymorphisms and hypodontia in humans. Samples consisted of genomic DNA of 50 affected individuals and 50 control subjects, with age above 16. For PAX9 promoter polymorphisms analysis, test and control groups were composed of 100 individuals. After DNA extraction, the regions of interest were amplyfied by polymerase chain reaction (PCR). The polymorphic sites were analysed by restriction length fragment polymorphism (RLFP). The gel bands were stained by silver nitrate. Monte Carlo simulations (Clump software) and Chi-square test (x2) were used for statistical analysis. Differences were considered significant when p<0.05. ARLEQUIN computer program was used to analyse haplotypic combinations in TGF BETA1 and PAX9 genes. The analysis showed that TIMP2 promoter polymorphism was not present in the studied population and that TGF BETA1 and MMP9 promoter polymorphisms are not associated with hypodontia. There was a positive correlation between the two PAX9 promoter polymorphisms and hypodontia / Doutorado / Histologia e Embriologia / Doutor em Biologia Buco-Dental

Made available in DSpace on 2014-06-12T18:06:57Z (GMT). No. of bitstreams: 2 arquivo6327_1.pdf: 804103 bytes, checksum: 63678f4331b844f0faeb4766a5bd6ccd (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2004 / A regulação da expressão gênica envolve uma complexa rede de interações entre fatores de transcrição e elementos regulatórios da região promotora dos genes. Dados experimentais disponíveis na literatura demonstram a importância de uma seqüência de 15 pares de base (pb) na regulação do gene SNM1(PSO2), necessário para o processo de reparação de lesões no DNA da levedura Saccharomyces cerevisiae. Estes dados foram fundamentais na elaboração da hipótese acerca da dispersão deste elemento na região promotora de outros genes de reparação e de sua importância na indução destes genes mediada por danos no DNA da levedura. Verificouse a presença desta seqüência de 15 pb nas regiões promotoras de outros genes de reparação de DNA, o que proporcionou a construção de uma matriz de peso relacionando nucleotídeos conservados, transições e transversões nas diferentes posições da seqüência consenso denominada seqüência consenso semelhante ao elemento DRE (Damage Response Element) do gene RAD2. Posteriormente, a análise de homologia foi expandida, utilizando ferramentas computacionais de análise matricial que proporcionam a geração de uma seqüência consenso identificada também em muitos outros genes desta levedura. A grande maioria não estando relacionada com processos de reparação ou metabolismo do DNA. Este elemento semelhante ao elemento regulatório DRE apresentou alta homologia com outras seqüências regulatórias presentes no genoma da levedura. O fato deste elemento estar presente na região promotora de quase um terço dos genes da levedura e de que sua presença parece não estar diretamente relacionada com a indução destes genes por agentes mutagênicos, sugerem fortemente que a seqüência semelhante ao elemento DRE descrita neste trabalho deve atuar como um elemento regulatório envolvido com mecanismos gerais de regulação da expressão gênica em S. cerevisiae

Memoria para optar al Título Profesional de Médico Veterinario / Las mascotas exóticas, especialmente los reptiles -ampliamente distribuidos por el mundo representan un alto riesgo para la Salud Pública, debido principalmente a su condición de portadores intestinales de Salmonella spp., estimándose que del total de casos de salmonelosis un 7% se asocia al contacto con reptiles (SAR). Del total de SAR un 15% aproximadamente presenta un cuadro invasivo, los cuales incluyen septicemia, meningitis, infección en cartílagos e inclusive la muerte. La invasividad de Salmonella se encuentra asociada a genes de virulencia, que se organizan principalmente en la isla de Patogenicidad 2 (SPI-2) de su genoma. En consideración a lo anterior el propósito de este estudio fue detectar genes de virulencia asociados a invasividad, en cepas de Salmonella spp. aisladas desde reptiles en cautiverio de la Región Metropolitana. En este estudio se seleccionaron cuatro genes de virulencia (spiA, sseG, ssaB, sscB) asociados a invasividad, específicamente a la sobrevivencia de esta bacteria al interior de macrófagos y su diseminación sistémica. De las 34 cepas analizadas, el perfil más frecuente encontrado fue spiA/sscB/sseG (35,2%), seguido por sscB/sseG/ssaB (8,8%), siendo los genes mayormente detectados sseG (91%), ssaB (71%) y sscB (61%), mientras que el gen spiA fue menor su detección (31%). Estos resultados constituyen la primera aproximación molecular de la potencial virulencia de cepas de Salmonella aislada desde reptiles en Chile. Se discuten los resultados con la variabilidad genética en cepas de diferentes fuentes animales y el hombre. / Exotic pets, especially reptiles, are widely distributed throughout the world, particularly in Chile, where a high percentage are intestinal carriers of Salmonella spp. (About 50%), representing a risk to public health. Thus, it is estimated that of all cases of salmonellosis in humans, about 6-7% is associated with contact with reptiles (RAS). Of total RAS, about 15% has a box-invasive, which include septicemia, meningitis, infection in cartilage and even death. Salmonella invasiveness is encoded in virulence genes that are organized primarily in Pathogenicity Island 2 (SPI-2). The purpose of this study was to detect genes associated with invasiveness virulence in Salmonella strains, isolated from reptiles in captivity in the Metropolitan Region. In this study, four virulence genes (spiA, sseG, ssaB, sscB) associated with invasiveness, and therefore, belonging to the pathogenicity island 2 were selected. These genes are related to the survival of the bacteria within macrophages and their systemic dissemination. Of the 34 strains tested, the most common profile was spiA/ sscB/ sseG (35.2%), followed by sscB/sseG/ssaB (8.8%), the most prevalent genes sseG (91%), ssaB (71%) and sscB (61%), while the spiA obtained a lower prevalence (31%). These results provide the first molecular approach of potential virulence of Salmonella strains isolated from reptiles in Chile. The results with the genetic viability in different strains of animals and humans sources are discussed.

Abstract Collagens IX, a non-fibrillar collagen, and XI, a fibrillar collagen, are minor components of cartilage collagen fibrils, which form a supportive meshwork in the cartilage extracellular matrix (ECM). Collagens IX and XI are known to be present also in other tissues, including the vitreous body of the eye, the intervertebral disc, the inner ear, and various tissues during embryonic development. Collagen IX is suggested to act as a macromolecular bridge between collagen fibrils and other ECM molecules, and it may be important for the cohesive and compressive properties of cartilage, as well as the long-term stability of articular cartilage. Collagen XI is speculated to have a role in regulating the fibril diameter, and it may participate in interactions with other ECM components. However, the role of neither collagen IX nor XI has been confirmed yet. As important but minor components of the cartilage ECM, collagens IX and XI are excellent candidates for relatively mild chondrodysplasias and even milder disease phenotypes involving cartilaginous tissues, such as non-syndromic hearing loss. There are in fact many reports describing defects in the genes for collagens IX and XI in patients with a variety of chondrodysplasias, including multiple epiphyseal dysplasia, Stickler syndrome, Marshall syndrome and otospondylomegaepiphyseal dysplasia. In order to screen the minor cartilage collagen genes for mutations, it is essential to know their gene structures. Therefore, the complete structures of the human COL9A1, COL9A2 and COL11A2 genes were characterized in this study. Also, to facilitate the analysis of the 5' region of the COL11A2 gene, the cDNA and partial genomic structure of the mouse Col11a2 gene were defined. The information obtained in this study was utilized in the mutation analysis of a family with non-ocular Stickler syndrome. The COL11A2 gene was analyzed with conformation sensitive gel electrophoresis (CSGE) and sequencing, and a heterozygous single-nucleotide mutation causing a premature termination codon was found in the affected family members. Studying the effect of the mutation on the RNA revealed that the nonsense mutation caused the skipping of a 54-bp exon, presumably through a pathway called nonsense-associated altered splicing.

>Magister Scientiae - MSc / Systemic lupus erythematosus is a chronic, inflammatory disease characterised by the production of autoantibodies which target particularly the nuclear components of multiple cell types throughout the body. MicroRNA’s have been well-established to regulate gene function by partial-, or complete binding to the 3’-UTR of the target genes, causing repression or complete degradation of the target gene. As a result, proteins normally produced by the targeted mRNA would exhibit a decrease in production.The aim of this study was to investigate the interactions between genes and microRNAs implicated in the pathogenesis of SLE. Objectives included curating lists of miRNAs and genes associated with lupus pathogenesis, to identify regulatory targets of miRNAs and genes targeted by miRNAs, and to find the intersections of these outputs. By examining the intersections of the resultant targets, we aimed to identify novel interactions using Pathway Analysis, which have not been previously reported in scientific literature, to be associated with the pathogenesis of SLE. Understanding the miRNA-gene target interactions in the progression of SLE may provide us with essential biomarkers and targets for disease diagnosis and therapy. / National Research Foundation (NRF) and DAAD

Although it was previously reported that Dictyostelium discoideum possessed a single ras gene (Ddras) that was maximally expressed during the pseudoplasmodial stage of development, a second ras gene (DdrasG), has been isolated and characterized. It encodes a protein that is similar to the protein encoded by Ddras and the human ras proteins. However, in contrast to Ddras, the DdrasG gene was only expressed during growth and early development. The two ras proteins may fulfill different functions: the DdrasG protein having a role during cell growth and the Ddras protein having a role in signal transduction during multicellular development. However, the expression of the DdrasG gene throughout development did not appear to have a detrimental effect on differentiation. Although other eukaryotic organisms possess more than one ras gene, D. discoideum is thus far unique in expressing different ras genes at different stages of development. Ras genes are members of a large ras-related multigene family that has been found in a wide variety of organisms. A ras-related gene was isolated from D. discoideum that hybridized to both the Ddras and DdrasG genes under low, but not under high stringency conditions. The predicted amino acid sequence shows a high degree of sequence identity with the human rap proteins and thus has been designated Ddrapl. During vegetative and early development a single 1.1 kb mRNA was present, but by aggregation this transcript was no longer detected and two new transcripts of 1.0 and 1.3 kb were observed and were present throughout the remainder of development. The maximum levels of the Ddrapl specific mRNAs appeared during aggregation and culmination, developmental stages where the levels of DdrasG and Ddras messages were declining. The reciprocal nature of the Ddrapl gene expression with respect to that of the two ras genes suggests the possibility that the ras and rap gene products in D. discoideum have antagonistic roles. Antibodies that are specific for the Ddras, DdrasG and Ddrapl proteins have been generated and can be used to help elucidate the biological functions of the individual proteins. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

The purpose of this investigation was to examine the structure of the murine cytomegalovirus (MCMV) genome and to study its expression during productive and non-productive infections caused by the virus. The kinetic complexity of MCMV DNA was not less than its molecular weight implying the absence of major reiterations. The restriction endonuclease EcoR^ cleaved this molecule into twenty-five fragments, which were present in the digest in equimolar amounts and ranged in molecular weights from 20 to 1 million. The sum of the molecular weights of the fragments was 136 million. The genomes of the 'K 181' and 'Smith' strains of MCMV appeared to share more than 99 percent of their sequences, although the DNAs exhibited slightly different fragmentation patterns when treated with EcoR^ and Hind III endonucleases. Control was exerted on the transcription of the MCMV genome at temporal, quantitative, and processing levels. During productive infections, approximately 25 percent of the genome was represented as stable transcripts in the cell at 6 hours post infection, i.e., before the onset of viral DNA synthesis, whereas RNA transcribed from 35 to 40 percent of the DNA was present in the cells in the later stages of infection. RNA sequences corresponding to 6 h (early) transcripts would be detected in the cell throughout the infectious cycle. Both 'early' and 'late' RNA comprised two RNA classes differing about 7 to 10 fold in concentration. Viral DNA synthesis in the host cell was required for the expression of 'late' genes since in the presence of inhibitors of protein and DNA synthesis only 'early' transcription occurred. Control was also exerted on the transport of transcripts from the nucleus to the cytoplasm of infected cells. Although RNA extracted from the nuclei of infected cells arose from 25 (early) and 35 (late) percent of the viral genome, transcripts from only 11 (early) and 15 (late) percent of the DNA were detected in the cytoplasm. Cells of mouse origin (3T3.cells), arrested in the G^ phase of the cell cycle, retained the viral genome in a non-replicating state, but could be induced to enter the lytic cycle by serum activation. Transcripts from 19 percent of the genome were observed in G^ arrested, MCMV-infected cells. Viral RNA in these cells comprised only one abundance class, which was similar to the scarce class in 'early' RNA from infected exponentially growing cells. Some evidence was also obtained for the transmission of latent MCMV genomes from mother to progeny. Cells cultured from embryos of infected mice did not normally produce infectious virus. However, the presence of the virus, at least in some of these cells, could be demonstrated by immunofluorescence, and by in-situ hybridization, using iodinated MCMV DNA as probe. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate