RESUMEN
With the rise in genetic screening both pre- and postnatally, new variances in genes are being recognized. Some are of unknown significance, while other known genetic expressions have obvious phenotypical expressions. Transient neonatal diabetes mellitus is a result of the duplication of chromosome 6q24, but little is known about the phenotypic expression of a triplication of chromosome 6q24. This case study presents an infant with a postnatally diagnosed triplication of chromosome 6q24, meconium pseudocyst, and multiple congenital anomalies with unknown genetic significance.
Asunto(s)
Anomalías Múltiples/diagnóstico , Quistes/congénito , Diabetes Mellitus/diagnóstico , Meconio , Quistes/diagnóstico , Humanos , Recién Nacido , MasculinoRESUMEN
Because mutations are inevitable, the genome of each cell in a multicellular organism becomes unique and therefore encodes a record of its ancestry. Here we coupled arbitrary single primer PCR with next-generation DNA sequencing to catalog mutations and deconvolve the phylogeny of cultured mouse cells. This study helps pave the way toward construction of retrospective cell-fate maps based on mutations accumulating in genomes of somatic cells.
Asunto(s)
Linaje de la Célula/genética , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Mutación , Análisis de Secuencia de ADN/métodos , Animales , Simulación por Computador , Genoma , Ratones , Filogenia , Reacción en Cadena de la Polimerasa/métodos , Reproducibilidad de los ResultadosAsunto(s)
Adenoviridae/genética , Genes Virales , Vectores Genéticos , Recombinación Genética , Secuencias Repetitivas de Ácidos Nucleicos/genética , Línea Celular , ADN Viral , Técnicas de Transferencia de Gen , Genoma Viral , Virus Helper/genética , Virus Helper/metabolismo , Humanos , Plásmidos/genética , Plásmidos/metabolismo , Transfección , Replicación ViralRESUMEN
In this study, we examined the ability of adenoviral (Ad) vectors to undergo homologous recombination. The lacZ gene was divided between two parental, first-generation vectors such that neither encoded a functional product but both shared 494 bp in common. The open reading frame could only be restored by homologous recombination. We observed beta-galactosidase activity only upon co-infection of both parental vectors and after the onset of viral DNA replication, creating a delay in expression of 24-36 hours in HeLa cells. At peak efficiency, this recombination vector system resulted in beta-galactosidase activity levels 100x above background and just 18x less than a conventional, first-generation vector in HeLa cells. After recombination, the resultant progeny vector genomes containing reconstituted expression cassettes were devoid of all viral genes and contained two packaging signals. These progeny genomes were efficiently packaged, could be separated from their parental vectors based on their lighter buoyant densities in CsCl gradients, and were subsequently used as functional gene transfer vectors. This novel recombination vector system should be useful for transferring large transgenes (because the carrying capacity of two Ad vectors can be exploited) or expressing any cytotoxic or Ad replication inhibitory protein (because the parental vectors exhibit no background expression).
Asunto(s)
Adenoviridae/genética , Vectores Genéticos , Operón Lac/genética , Recombinación Genética , Células HeLa , HumanosRESUMEN
The construction and amplification of adenoviral (Ad) vectors expressing biologically active transgenes that are cytotoxic or inhibit Ad replication can be extremely difficult, if not impossible. In this study, we harnessed the ability of Ad genomes to undergo efficient homologous recombination to reconstitute the adeno-associated virus (AAV) rep78 gene, a cytotoxic gene that strongly inhibits Ad replication, which was divided between two parental, first-generation Ad vectors. A functional open reading frame was generated by recombination only upon co-infection of both parental vectors and after the onset of viral DNA replication. We were able to amplify both parental rep78 vectors to normal titers without any signs of inhibition or toxicity and could use them to generate progeny vectors containing a functional rep78 gene without any Ad genes. Using this vector recombination system in AAV rescue assays demonstrated that no Ad protein was essential for Rep78 mediated rescue of AAV ITR flanked DNA from plasmid or Ad backbones; the amount of rescue product generated was substantially greater in the presence of Ad infection; neither cellular nor viral DNA replication was necessary for rescue to occur; and progeny vector genomes were efficiently co-replicated along with conventional, first-generation Ad vectors.
Asunto(s)
Adenoviridae/genética , Proteínas de Unión al ADN/genética , Técnicas de Transferencia de Gen , Vectores Genéticos , Recombinación Genética , Proteínas Virales/genéticaRESUMEN
To achieve stable gene transfer into human hematopoietic cells, we constructed a new vector, DeltaAd5/35.AAV. This vector has a chimeric capsid containing adenovirus type 35 fibers, which conferred efficient infection of human hematopoietic cells. The DeltaAd5/35.AAV vector genome is deleted for all viral genes, allowing for infection without virus-associated toxicity. To generate high-capacity DeltaAd5/35.AAV vectors, we employed a new technique based on recombination between two first-generation adenovirus vectors. The resultant vector genome contained an 11.6-kb expression cassette including the human gamma-globin gene and the HS2 and HS3 elements of the beta-globin locus control region. The expression cassette was flanked by adeno-associated virus (AAV) inverted terminal repeats (ITRs). Infection with DeltaAd5/35.AAV allowed for stable transgene expression in a hematopoietic cell line after integration into the host genome through the AAV ITR(s). This new vector exhibits advantages over existing integrating vectors, including an increased insert capacity and tropism for hematopoietic cells. It has the potential for stable ex vivo transduction of hematopoietic stem cells in order to treat sickle cell disease.