RESUMEN
RNA interference consists in specific mRNA degradation in response to introduction of a double-stranded RNA, homologous in nucleotide sequence. RNA interference was found in eukaryotes and is used in genomics as a powerful method to determine the functions of genes with known nucleotide sequences. RNA interference is considered as a tool of protection against viruses and harmful consequences of mobile elements' transposals. The involvement of the components of RNA interference is considered in spermatogenesis of Drosophila melanogaster and regulation of the expression of genes in Caenorhabditis elegans responsible for temporal patterns of development. The role of RNQA interference in stem cell formation and functioning is also considered.
Asunto(s)
Diferenciación Celular/genética , Regulación del Desarrollo de la Expresión Génica , Interferencia de ARN , Animales , Drosophila melanogaster , Nematodos , Espermatogénesis/genética , Células Madre/citología , Células Madre/fisiologíaRESUMEN
Data on RNA interference, that is, posttranscriptional gene silencing by homologous double-stranded (ds) RNA, are reviewed. Gene silencing caused by exogenous dsRNA in artificial systems and observed in transgenic organisms carrying additional gene copies is considered. Data are summarized on the mechanism that arose during evolution of the Drosophila melanogaster genome to suppress repetitive genes with the use of dsRNA and thereby to prevent male sterility. The role of dsRNA in inhibiting expression and transposition of mobile elements is discussed on the basis of authors own and published findings.
Asunto(s)
Células Eucariotas/fisiología , Silenciador del Gen , ARN Bicatenario/fisiología , Animales , Drosophila/genética , Hongos/genética , Regulación de la Expresión Génica de las Plantas , Plantas Modificadas Genéticamente , Procesamiento Postranscripcional del ARN , Supresión GenéticaRESUMEN
Specific inhibition of gene expression by exogenous homologous double-stranded RNA (dsRNA) in invertebrates and in the early development of vertebrates is termed RNA interference. Cultured cells were cotransfected with reporter plasmids and dsRNA. The inhibitor effect on reporter gene expression depended on the extent of homology between dsRNA and the target gene. RNA interference was also studied in cells cotransfected with plasmids directing synthesis of sense and antisense RNAs. Production of antisense RNA only slightly inhibited expression of the reporter gene. Simultaneous expression of both sense and antisense RNAs from a special plasmid did not inhibit expression of the reporter construct.
Asunto(s)
Drosophila melanogaster/genética , Regulación de la Expresión Génica , ARN Bicatenario/genética , Animales , Genes de Insecto , Genes Reporteros , Operón Lac , Plásmidos , ARN sin Sentido , TransfecciónRESUMEN
BACKGROUND: The injection of double-stranded RNA (dsRNA) has been shown to induce a potent sequence-specific inhibition of gene function in diverse invertebrate and vertebrate species. The homology-dependent posttranscriptional gene silencing (PTGS) caused by the introduction of transgenes in plants may be mediated by dsRNA. The analysis of Caenorhabditis elegans mutants impaired with dsRNA-mediated silencing and studies in plants implicate a biological role of dsRNA-mediated silencing as a transposon-repression and antiviral mechanism. RESULTS: We investigated the silencing of testis-expressed Stellate genes by paralogous Su(Ste) tandem repeats, which are known to be involved in the maintenance of male fertility in Drosophila melanogaster. We found that both strands of repressor Su(Ste) repeats are transcribed, producing sense and antisense RNA. The Stellate silencing is associated with the presence of short Su(Ste) RNAs. Cotransfection experiments revealed that Su(Ste) dsRNA can target and eliminate Stellate transcripts in Drosophila cell culture. The short fragment of Stellate gene that is homologous to Su(Ste) was shown to be sufficient to confer Su(Ste)-dependent silencing of a reporter construct in testes. We demonstrated that Su(Ste) dsRNA-mediated silencing affects not only Stellate expression but also the level of sense Su(Ste) RNA providing a negative autogenous regulation of Su(Ste) expression. Mutation in the spindle-E gene relieving Stellate silencing also leads to a derepression of the other genomic tandem repeats and retrotransposons in the germline. CONCLUSIONS: Homology-dependent gene silencing was shown to be used to inhibit Stellate gene expression in the D. melanogaster germline, ensuring male fertility. dsRNA-mediated silencing may provide a basis for negative autogenous control of gene expression. The related surveillance system is implicated to control expression of retrotransposons in the germline.
Asunto(s)
Proteínas de Drosophila , Drosophila melanogaster/genética , Silenciador del Gen , Genes de Insecto , Proteínas de Insectos/genética , Proteínas Quinasas , ARN Bicatenario/fisiología , Proteínas Represoras/genética , Adenosina Trifosfatasas/genética , Animales , Animales Modificados Genéticamente , Células Cultivadas , Femenino , Genes Reporteros , Proteínas de Insectos/biosíntesis , Masculino , Mutación , ARN sin Sentido/biosíntesis , ARN Mensajero/biosíntesis , Proteínas Represoras/biosíntesis , Retroelementos , Homología de Secuencia de Ácido Nucleico , Secuencias Repetidas en Tándem , Testículo/metabolismoRESUMEN
The action of information stress for 14 days leads to the development of immunosuppression, which is manifested by the suppression of humoral response to sheep red blood cells (SRBC) and the decrease of resistance to Langat virus having low pathogenicity. As shown in this investigation, an immunomodifier, purified staphylococcal toxoid (PST), protects experimental animals from the immunosuppressive effect of information stress. After the injection of PST to stress-affected mice in doses of 15 or 1.5 binding units per animal on days 9, 11 and 13 of the experiment their humoral response to SRBC and resistance to Langat virus are partially restored (by 45-60%).
Asunto(s)
Adyuvantes Inmunológicos/uso terapéutico , Tolerancia Inmunológica/efectos de los fármacos , Toxoide Estafilocócico/uso terapéutico , Estrés Psicológico/inmunología , Animales , Animales Lactantes , Formación de Anticuerpos/efectos de los fármacos , Modelos Animales de Enfermedad , Evaluación Preclínica de Medicamentos , Virus de la Encefalitis Transmitidos por Garrapatas , Encefalitis Transmitida por Garrapatas/tratamiento farmacológico , Encefalitis Transmitida por Garrapatas/etiología , Encefalitis Transmitida por Garrapatas/inmunología , Tolerancia Inmunológica/inmunología , Masculino , Ratones , Ratones Endogámicos BALB C , Pase Seriado , Estrés Psicológico/complicaciones , Estrés Psicológico/tratamiento farmacológico , Factores de TiempoRESUMEN
The results of the physico-chemical and hygienic investigations of smoked sausages produced according to the improved technology were compared to those of routine products. The changes in the content of smoking substances in uncooked smoked sausage depend on the duration of smoking and drying. Microstructural and microbiological data, as well as carcinogenic compounds detected in the samples studied have been presented. It has been shown that the use of vacuum evaporation improves the product structure and significantly decreases the content of carcinogenic substances in smoked sausages, as well as makes better their taste and scent, that leads to the improvement of consumer's properties of the product.