RESUMO
BACKGROUND: Unintentional weight loss is frequently observed in cancer patients. Nutritional therapy is essential, and dietary counselling is the first step. The present study aimed to explore the nutrient intake and food patterns in weight-stable and weight-losing patients with non-small cell lung cancer (NSCLC) during anti-neoplastic treatment. METHODS: Patients with NSCLC (n = 62) were observed during first-line systemic anti-neoplastic treatment. Body weight and dietary intake were assessed on the first and second cycle, and after completing three cycles of treatment. Longitudinal changes were analysed in three groups: weight stable, weight losers and mixed weight. RESULTS: Nutrient intake did not change during treatment in weight stable, although weight losers significantly increased the relative protein intake. Weight stable maintained the food pattern during treatment apart from a decreased consumption of oral nutritional support (ONS). At baseline, weight losers were characterised by pretreatment weight loss, high consumption of ONS, as well as low consumption of grains and animal products. During treatment, weight losers increased the consumption of protein, fatty foods and ONS but decreased the consumption of sweets and alcohol. CONCLUSIONS: Large heterogeneity in nutrient and food intake was observed in NSCLC patients during anti-neoplastic treatment. Weight losers and weight stable had a similar nutrient intake although protein intake increased in weight losers. Grains and animal products were lower and ONS higher in weight losers compared to weight stable during treatment. Weight losers further increased the consumption of ONS and fatty foods, while the consumption of sweets and alcohol decreased during treatment.
Assuntos
Antineoplásicos/efeitos adversos , Carcinoma Pulmonar de Células não Pequenas/fisiopatologia , Dieta/estatística & dados numéricos , Neoplasias Pulmonares/fisiopatologia , Nutrientes/análise , Idoso , Peso Corporal , Carcinoma Pulmonar de Células não Pequenas/terapia , Dieta/efeitos adversos , Inquéritos sobre Dietas , Ingestão de Alimentos , Feminino , Humanos , Estudos Longitudinais , Neoplasias Pulmonares/terapia , Masculino , Pessoa de Meia-Idade , Avaliação Nutricional , Estado Nutricional , Magreza/induzido quimicamente , Magreza/fisiopatologia , Magreza/prevenção & controle , Redução de PesoRESUMO
Pit, Oct, Unc (POU) homeo domain transcription factors have been implicated in various developmental processes, including cell division, differentiation, specification, and survival of specific cell types. Although expression of the transcription factor Oct-6 in oligodendroglia is confined to the promyelin stage and is downregulated at the myelin stage of development, the effect of Oct-6 overexpression on oligodendrocyte development has not been established. Here we show that transgenic animals overexpressing Oct-6 at late oligodendrocyte development develop a severe neurologic syndrome characterized by action tremors, recurrent seizures, and premature death. Axons in the central nervous system of Oct-6 transgenics were hypomyelinated, hypermyelinated, or dysmyelinated, and ultrastructural analyses suggested that myelin formation was premature. The vulnerability of developing oligodendroglia to Oct-6 deregulation provides evidence that the POU factor may play a direct role in myelin disease pathogenesis in the mammalian CNS.
Assuntos
Sistema Nervoso Central/metabolismo , Regulação da Expressão Gênica , Proteína Básica da Mielina/genética , Doenças do Sistema Nervoso/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Animais , Axônios/metabolismo , Axônios/patologia , Axônios/ultraestrutura , Northern Blotting , Western Blotting , Sistema Nervoso Central/crescimento & desenvolvimento , Sistema Nervoso Central/ultraestrutura , Clonagem Molecular , DNA/análise , DNA/genética , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Camundongos Transgênicos , Microscopia Eletrônica , Mutagênese Insercional , Proteína Básica da Mielina/metabolismo , Bainha de Mielina/genética , Bainha de Mielina/metabolismo , Doenças do Sistema Nervoso/genética , Doenças do Sistema Nervoso/patologia , Fator 6 de Transcrição de Octâmero , Reação em Cadeia da Polimerase , RNA/análise , RNA/metabolismoRESUMO
Deletion of the yeast gene ACB1 encoding Acb1p, the yeast homologue of the acyl-CoA-binding protein (ACBP), resulted in a slower growing phenotype that adapted into a faster growing phenotype with a frequency >1:10(5). A conditional knockout strain (Y700pGAL1-ACB1) with the ACB1 gene under control of the GAL1 promoter exhibited an altered acyl-CoA profile with a threefold increase in the relative content of C18:0-CoA, without affecting total acyl-CoA level as previously reported for an adapted acb1Delta strain. Depletion of Acb1p did not affect the general phospholipid pattern, the rate of phospholipid synthesis, or the turnover of individual phospholipid classes, indicating that Acb1p is not required for general glycerolipid synthesis. In contrast, cells depleted for Acb1p showed a dramatically reduced content of C26:0 in total fatty acids and the sphingolipid synthesis was reduced by 50-70%. The reduced incorporation of [(3)H]myo-inositol into sphingolipids was due to a reduced incorporation into inositol-phosphoceramide and mannose-inositol-phosphoceramide only, a pattern that is characteristic for cells with aberrant endoplasmic reticulum to Golgi transport. The plasma membrane of the Acb1p-depleted strain contained increased levels of inositol-phosphoceramide and mannose-inositol-phosphoceramide and lysophospholipids. Acb1p-depleted cells accumulated 50- to 60-nm vesicles and autophagocytotic like bodies and showed strongly perturbed plasma membrane structures. The present results strongly suggest that Acb1p plays an important role in fatty acid elongation and membrane assembly and organization.
Assuntos
Proteínas de Transporte/fisiologia , Proteínas Fúngicas/fisiologia , Esfingolipídeos/biossíntese , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Membrana Celular , Inibidor da Ligação a Diazepam , Ácidos Graxos/biossíntese , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Fosfatidiletanolaminas/biossíntese , Fosfatidilinositóis/biossíntese , Fosfatidilserinas/biossíntese , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/fisiologiaRESUMO
c-myc is a member of the helix-loop-helix/leucine zipper family of proteins that modulate the transcriptional activity of specific target genes. Although aberrant c-myc expression has been reported to play a role in multistage carcinogenesis in astrocytic gliomas, little is known about the effects of the expression of c-myc on oligodendrocytes. Using transgenic animals expressing a human c-myc oncogene under transcriptional control of the myelin basic protein gene, we investigated the effect of overexpression of this oncogene in oligodendrocytes. The MBP/c-myc transgenic mice developed severe neurological disturbances characterized by action tremors and recurrent seizures, and premature death during postnatal weeks three to five. Affected transgenic mice of various strains had severely hypomyelinated central nervous systems and expressed low levels of c-myc, myelin basic protein (MBP) and proteolipid protein (PLP) mRNAs in the brain. These c-myc transgenic mice also exhibited an increased number of TUNEL positive nuclei, which in most cases were located in cells that expressed c-myc, as judged by double immunohistochemistry. There was no evidence of brain tumors in the c-myc transgenic mice, including heterozygous mice from two strains that had normal lifespans. These observations indicate that the myelin deficiency observed in the MBP/c-myc transgenic animals results from a cytotoxic effect of the c-myc transgene.
Assuntos
Sistema Nervoso Central/citologia , Sistema Nervoso Central/metabolismo , Proteína Básica da Mielina/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Animais , Apoptose , Sobrevivência Celular , Humanos , Camundongos , Camundongos Transgênicos , Proteína Básica da Mielina/genética , Oligodendroglia/citologia , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , TransgenesRESUMO
A mammalian transmission-expression vector has been constructed based on the plasmid pBR322 and using the transcriptional signals from the Akv murine leukemia virus (AkvMuLV) to control the expression of the neo gene. The transmission vector pL psi PLneo, when transfected into the psi 2 cell line, confers G-418 resistance on recipient cell clones which produce viral particles encapsidating the transcripts of the vector. Cultures of such clones produce viral particles of titers up to 10(5) cfu/ml. The pL psi PLneo vector has two unique restriction sites which can be used for the insertion of new DNA material.
Assuntos
Genes Virais , Vetores Genéticos , Vírus da Leucemia Murina/genética , Plasmídeos , Animais , Enzimas de Restrição do DNA , DNA Recombinante/metabolismo , Camundongos , Transcrição GênicaRESUMO
Proteomics is an emerging area of research of the post-genomic era that deals with the global analysis of gene expression using a plethora of techniques to resolve (high resolution two-dimensional polyacrylamide gel electrophoresis, 2D PAGE), identify (peptide sequencing by Edman degradation, mass spectrometry, Western immunoblotting, etc.), quantitate and characterize proteins, as well as to store (comprehensive 2D PAGE databases), communicate and interlink protein and DNA sequence and mapping information from genome projects. Here we review the current status as well as applications of human and mouse proteomic 2D PAGE databases that are being systematically constructed for the global analysis of gene expression in both health and disease (http://biobase.dk/cgi-bin/celis). Furthermore, we discuss the problems one faces when using powerful proteomic technology to study heterogeneous tissue and tumor biopsies, and emphasize the importance of building comprehensive databases that contain a critical mass of information for both known and novel proteins in normal and disease conditions.
Assuntos
Bases de Dados Factuais , Proteínas/genética , Animais , Redes de Comunicação de Computadores , Eletroforese em Gel Bidimensional/métodos , Humanos , CamundongosRESUMO
Myelin is necessary for the conduction of high frequency and high velocity nerve impulses in the central nervous system of mammals, and severe neurological disturbances develop as a result of myelin loss. In this report, we have characterized changes in the brain proteomic profile of transgenic mice that develop a c-myc-induced degenerative disorder of myelin. Marked differences were seen in the accumulation of cytoskeletal proteins associated with the pathological condition fibrous gliosis in the optic nerves of affected animals, including upregulation of glial fibrillary acid protein and vimentin. In addition, the expression of several major myelin proteins, including five isoforms of myelin basic protein, four isoforms of cyclic nucleotide 3'-phosphodiesterase, and myelin-associated glycoprotein, was markedly reduced in the brains of c-myc transgenic mice as revealed by immunocytochemistry and by two-dimensional immunoblots. A number of novel proteomic disease marker candidates were revealed, which displayed pronounced changes in their expression profile. Sequence determination of these proteins and molecular cloning of their mRNAs will provide an opportunity to further evaluate their roles in the disease process.
Assuntos
Sistema Nervoso Central/química , Bainha de Mielina/metabolismo , Degeneração Neural/metabolismo , Proteínas/análise , Proteínas Proto-Oncogênicas c-myc/fisiologia , 3',5'-AMP Cíclico Fosfodiesterases/análise , Animais , Sistema Nervoso Central/patologia , Expressão Gênica , Humanos , Camundongos , Camundongos Transgênicos , Proteína Básica da Mielina/análise , Proteína Básica da Mielina/genética , Degeneração Neural/patologia , Oligodendroglia/enzimologia , Proteínas Proto-Oncogênicas c-myc/genéticaRESUMO
The basic helix-loop-helix transcription factor c-Myc is a potent trigger of programmed cell death when overexpressed during late oligodendrocyte development in transgenic mice. Here we provide evidence that c-Myc can act synergistically with the Pit, Oct, Unc homeodomain transcription factor Oct-6 to produce myelin disease pathogenesis in transgenic mice. More than 70% of c-myc/Oct-6 bitransgenic mice, obtained from crosses between phenotypically normal heterozygous mice of various My (c-Myc) and Oc (Oct-6) transgenic strains that express c-myc and oct-6 transgenes under transcriptional control of the myelin basic protein gene, developed severe neurological disturbances characterized by action tremors, recurrent seizures, and premature death. Affected bitransgenic mice exhibited multiple hypomyelinated lesions in the white matter that did not stain with myelin-specific antibodies against myelin basic protein, proteolipid protein, CNPase, and myelin-associated glycoprotein. The mice also exhibited a larger number of terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end-labeling positive cells in the white matter as well as ultrastructural evidence of glial cell death and astrogliosis. These observations indicate that the myelin lesions observed in the c-myc/oct-6 bitransgenic mice result from the untimely programmed cell death of oligodendroglia and that the c-myc and oct-6 transgenes act synergistically in producing the lesions.
Assuntos
Apoptose , Proteína Básica da Mielina/deficiência , Oligodendroglia/metabolismo , Proteínas Proto-Oncogênicas c-myc/fisiologia , Fatores de Transcrição/fisiologia , Animais , Sequência de Bases , Primers do DNA , Imuno-Histoquímica , Camundongos , Camundongos Transgênicos , Microscopia Eletrônica , Fator 6 de Transcrição de Octâmero , Oligodendroglia/citologia , Proteínas Proto-Oncogênicas c-myc/genética , Fatores de Transcrição/genéticaRESUMO
We have characterized a strain of double transgenic mice with simian virus 40 large tumor antigen and prokaryotic lacZ under the control of the myelin basic protein promoter that develops spindle-cell sarcomas and osteogenic sarcomas at 5-7 months of age. Although poorly differentiated, the spindle-cell sarcomas were characterized as malignant Schwannomas based on their neural association, the presence of basal lamina, and expression of Schwann cell-specific genes. The osteogenic sarcomas were often multiple and appeared predominantly in the facial bones, less frequently in the ribs and vertebral column, and only rarely in the appendicular skeleton. Benign osteoblastic lesions were often observed adjacent to these sarcomas. Both the osteoblastic cells in the facial skeleton and Schwann cells are regarded as neural crest derivatives. The biological properties and anatomical location of these tumors suggest that they may share a common origin from the neural crest or its derivatives. R.P. Bolande [Hum. Pathol. (1974) 5, 409-429] introduced the term neurocristopathy as a unifying concept to describe such lesions arising from the neural crest or its derivatives. Cell lines established from both bone and Schwann cell tumors arising in these transgenic mice express simian virus 40 large tumor antigen mRNA as well as functional large tumor antigen. Such cell lines are potentially valuable in the search for markers that identify mammalian neural crest derivatives.
Assuntos
Neoplasias Ósseas/patologia , Crista Neural/patologia , Neurilemoma/patologia , Osteossarcoma/patologia , Animais , Antígenos Transformantes de Poliomavirus/análise , Antígenos Transformantes de Poliomavirus/genética , Northern Blotting , Neoplasias Ósseas/genética , Neoplasias Ósseas/ultraestrutura , Modelos Animais de Doenças , Camundongos , Camundongos Transgênicos , Neurilemoma/genética , Neurilemoma/ultraestrutura , Osteossarcoma/genética , Osteossarcoma/ultraestrutura , RNA Neoplásico/genética , RNA Neoplásico/isolamento & purificação , Vírus 40 dos Símios/genética , Células Tumorais Cultivadas , beta-Galactosidase/análise , beta-Galactosidase/genéticaRESUMO
We investigated the effects of increasing the concentration of intracellular cyclic adenosine monophosphate (cAMP) on genes associated with oligodendrocyte differentiation in an immortalized glial cell line, 6E12, derived from the spinal cord of an MBP-SV40 large T-antigen transgenic mouse. Raising intracellular levels of cAMP induced expression of oligodendrocyte differentiation antigens recognized by O4 and anti-galactocerebroside antibodies, up-regulated expression of the proteolipid protein (PLP) gene, and down-regulated glial fibrillary acidic protein (GFAP) expression. There was no treatment effect on myelin-associated glycoprotein (MAG) expression. These phenotypic changes are consistent with oligodendrocyte differentiation. Treatment of 6E12 cells with dibutyryl cyclic AMP (DBC) down-regulated myelin basic protein (MBP) gene expression, perhaps, because it also up-regulated expression of a putative MBP repressor SCIP/Tst-1. Moreover, the 6E12 cells expressed high levels of MBP mRNA but no MBP translation products were detected in the presence or absence of DBC. This immortalized glial cell line is proposed as a CNS model for cAMP-modulated myelin gene expression and for post-transcriptional regulation of MBP.
Assuntos
AMP Cíclico/farmacologia , Oligodendroglia/efeitos dos fármacos , Animais , Antígenos/biossíntese , Northern Blotting , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Ensaio de Imunoadsorção Enzimática , Expressão Gênica/efeitos dos fármacos , Proteína Glial Fibrilar Ácida/biossíntese , Proteína Glial Fibrilar Ácida/genética , Imuno-Histoquímica , Camundongos , Camundongos Transgênicos , Proteína Básica da Mielina/biossíntese , Proteína Básica da Mielina/genética , Proteínas da Mielina/biossíntese , Proteínas da Mielina/genética , Proteína Proteolipídica de Mielina , Glicoproteína Associada a Mielina , Oligodendroglia/citologia , Testes de Precipitina , Processamento Pós-Transcricional do RNA/efeitos dos fármacos , Medula Espinal/citologiaRESUMO
To study the effect of SV40 large T-antigen expression in myelin-forming cells of both the central and peripheral nervous system, a series of transgenic mice were generated expressing the SV40 large T-antigen under control of the myelin basic protein (MBP) promoter. Two neurologic phenotypes, designated A and B, appeared among individual transgenic founders and their progeny. The A mice developed a severe action tremor at about 10 days of age that progressed into periods of convulsions and early death by three to four weeks of age. In contrast, the B mice exhibited a progressive hindlimb ataxia and had a more normal lifespan. The A mice displayed hypomyelinating lesions in the central nervous system (CNS), whereas the B mice had lesions in either the peripheral nervous system (PNS) alone or in both the PNS and CNS. Immunohistochemical staining of spinal cord sections of a type A mouse showed a substantial depletion in MBP. Moreover, T-antigen-positive cells appeared predominantly in white matter tracts as randomly distributed single cells. Double labeling immunocytochemistry demonstrated that some of these T-antigen-positive cells were positive for oligodendrocyte differentiation markers MBP and O4. Thus, T-antigen expression appeared to coincide with a terminal stage of oligodendrocyte differentiation.
Assuntos
Antígenos Transformantes de Poliomavirus/biossíntese , Doenças Desmielinizantes/genética , Proteína Básica da Mielina/metabolismo , Bainha de Mielina/fisiologia , Animais , Antígenos Transformantes de Poliomavirus/imunologia , Ataxia/genética , Ataxia/fisiopatologia , Sistema Nervoso Central/metabolismo , Sistema Nervoso Central/ultraestrutura , Clonagem Molecular , DNA/química , Doenças Desmielinizantes/metabolismo , Feminino , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Camundongos Transgênicos , Microscopia Eletrônica , Proteína Básica da Mielina/genética , Bainha de Mielina/ultraestrutura , Oligodendroglia/metabolismo , Nervos Periféricos/metabolismo , Nervos Periféricos/ultraestrutura , Fenótipo , Regiões Promotoras Genéticas/genética , Medula Espinal/ultraestrutura , Tremor/genéticaRESUMO
To better understand the process of multistage carcinogenesis in Schwann cells, we have attempted to isolate novel candidate genes involved in neoplastic progression of mouse malignant Schwannoma cells. The semi-differentiated Schwannoma cell line 56-24 and the less differentiated Schwannoma cell line 64-39 were established from peripheral nerve sheath tumors arising in transgenic mice of the MBP/SV40 large T strain Tg29. By using the chemical cross-linking subtraction technique, we have cloned a novel murine cDNA that detects pronounced expression in 56-24 cells but not in 64-39 cells. The longest open reading frame of the cDNA predicts a peptide showing 95% amino acid sequence homology to the recorded sequence of the human immunophilin homolog huFKBPr38, one of a family of proteins that are thought to interface with a wide range of intracellular signal transduction systems. The predicted open reading frame of the corresponding gene, named muFKBP38, encodes a 38 kDa protein that harbors an FK-binding protein (FKBP) domain that is 36% identical to that of muFKBP52, a three-unit tetratricopeptide repeat and a consensus leucine-zipper repeat. Although muFKBP38 mRNA was detected in both neurons and glial cells, pronounced expression of the immunophilin homolog appeared in various classes of neurons associated with the hippocampal formation, as shown by in situ hybridization analysis of adult mouse brains. Taken together, these data indicate that muFKBP38 is (i) a novel potential marker for semi-differentiated Schwannomas, (ii) may form homomultimers and/or interact with other proteins, and (iii) may have a role in neurons associated with memory function.
Assuntos
Imunofilinas/genética , Neurilemoma/genética , Neurônios/metabolismo , Proteínas de Ligação a Tacrolimo , Sequência de Aminoácidos , Animais , Sequência de Bases , Encéfalo/metabolismo , Encéfalo/patologia , Sistema Nervoso Central/citologia , Clonagem Molecular , DNA Complementar , Regulação Neoplásica da Expressão Gênica , Humanos , Hibridização In Situ , Camundongos , Dados de Sequência Molecular , Homologia de Sequência de Aminoácidos , Células Tumorais CultivadasRESUMO
Members of the phospholipase D (PLD) superfamily are defined by the conserved HXKXXXXD motif, which is essential for the catalytic function of mammalian PLD. PLD enzymes are thought to play roles in signal transduction and membrane vesicular trafficking in mammalian cells. Here we describe a 54-kDa novel murine polypeptide (designated SAM-9) that is predicted to be a membrane-associated member of the PLD superfamily. SAM-9 shares 40, 30, and 29% amino acid identity with potential orthologs, in vaccinia virus, Caenorhabditis elegans, and Dictyostelium discoideum, respectively, and belongs to a subclass of PLD homologs in which the second HXKXXXXD motif is imperfect and harbors a conserved Asp to Glu substitution. The sam-9 gene has more than eight exons, and the two HXKXXXXD motifs are encoded by two highly conserved exons. The expression of the sam-9 gene is greater in the brain than in non-nervous tissue and appears to be predominantly of neuronal origin. sam-9 expression is pronounced in mature neurons of the forebrain and appears to be turned on at late stages of neurogenesis as revealed by in situ hybridization analysis of sam-9 expression during postnatal development of the hippocampal formation and the primary somatosensory cortex.
Assuntos
Proteínas do Tecido Nervoso/biossíntese , Neurônios/enzimologia , Fosfolipase D/biossíntese , Prosencéfalo/crescimento & desenvolvimento , Sequência de Aminoácidos , Sequência de Bases , Diferenciação Celular , Clonagem Molecular , Sequência Conservada , DNA Complementar/genética , Hipocampo/enzimologia , Hibridização In Situ , Dados de Sequência Molecular , Família Multigênica , Proteínas do Tecido Nervoso/genética , Especificidade de Órgãos , Lobo Parietal , Fosfolipase D/genética , Prosencéfalo/citologia , Prosencéfalo/embriologia , Prosencéfalo/enzimologia , Homologia de Sequência de Aminoácidos , Córtex Somatossensorial/enzimologia , Distribuição Tecidual , Regulação para CimaRESUMO
Transgenic mice were generated using a construct that encodes mouse polyoma virus large T antigen, one of three oncogenic products of the "early region" of the polyoma viral genome. Of 16 transgenic families developed, 1 was characterized by a neurologic disorder consisting of constant tremor and recurrent seizures. Morphologic analysis of the central nervous system (CNS) of affected transgenic mice included: classical light and electron microscopic examination; immunohistochemical assessment of the presence and localization of myelin-specific proteins, of the astrocyte marker glial fibrillary acidic protein, of the oligodendrocyte marker galactosyl cerebroside, and of large T; double immunolabeling of glial fibrillary acidic protein or galactosyl cerebroside and large T to identify the CNS cell type in which large T is expressed; and in situ hybridization to study myelin basic protein gene expression. Our results suggest that polyoma large T is expressed in astrocytes, possibly resulting in altered glial-glial interactions causing impaired oligodendroglial development and secondary dysmyelination. Transgenic oligodendrocytes exhibit features of immaturity, failing to myelinate axons properly and producing morphologic phenotypes of early stages of myelination, such as numerous mesaxonal profiles. Myelin proteins are markedly reduced in transgenic CNS, and myelin basic protein transcripts, while present, are generally decreased. We believe that expression of large T in astrocytes could influence the complex and dynamic interactions between astrocytes and oligodendrocytes, perhaps with regard to the molecular (trophic) signals in the local CNS environment, bringing about arrested oligodendroglial maturation and hypomyelination. This raises intriguing questions concerning the importance of glial-glial interactions in the CNS and the complex levels of control involved in biological expression of genetic information in glial cells.
Assuntos
Antígenos de Neoplasias/análise , Antígenos Transformantes de Poliomavirus/análise , Antígenos Virais/análise , Astrócitos/imunologia , Doenças do Sistema Nervoso Central/etiologia , Camundongos Transgênicos/imunologia , Bainha de Mielina/fisiologia , Polyomavirus/imunologia , Animais , Antígenos de Neoplasias/fisiologia , Antígenos Transformantes de Poliomavirus/fisiologia , Antígenos Virais/fisiologia , Astrócitos/fisiologia , Astrócitos/ultraestrutura , Northern Blotting , Southern Blotting , Química Encefálica , Comunicação Celular/fisiologia , Doenças do Sistema Nervoso Central/fisiopatologia , DNA Viral/análise , DNA Viral/genética , Feminino , Galactosilceramidas/análise , Proteína Glial Fibrilar Ácida/análise , Imuno-Histoquímica , Masculino , Camundongos , Microscopia Eletrônica , Proteínas da Mielina/análise , Hibridização de Ácido Nucleico , Oligodendroglia/imunologia , Oligodendroglia/fisiologia , Oligodendroglia/ultraestrutura , Regiões Promotoras Genéticas , RNA Mensageiro/análiseRESUMO
Among a series of 44 transgenic families established after microinjection into fertilized eggs of a plasmid DNA where the structural gene for the large T antigen of polyoma virus is located downstream from the viral early promoter-enhancer region, one family with a hereditary neurological disorder was observed. At about three weeks of age, these animals developed a syndrome of constant tremor with recurrent seizures. Histological and ultra-structural examination revealed extensive dysmyelination in the white matter of the brain stem, cerebellum and spinal cord, as well as of peripheral nerves. This phenotype is reminiscent of that of the mouse "twitcher" (twi) mutant and of the human hereditary leukodystrophies. Expression of the viral sequences, assayed by Northern analysis and immunolabeling of T antigen, occurred predominantly in cells of the central nervous system. Integration of the transgene was mapped by in situ hybridization on metaphasic plaques in region B-C1 of chromosome 12 (where the twi locus was previously localized). Long-term cultures of cells with neural characteristics could be established readily from the brain of the transgenic mice.