Asunto(s)
Región de Flanqueo 5'/genética , Proteínas del Ojo/genética , Proteínas de la Membrana/genética , Polimorfismo Genético , Cromosomas Humanos Par 17 , Islas de CpG , Cartilla de ADN , Frecuencia de los Genes , Genotipo , Humanos , Epidemiología Molecular , Proteínas Circadianas Period , Reacción en Cadena de la Polimerasa , Proteínas R-SNARE , Eliminación de SecuenciaRESUMEN
Biological circadian clocks are endogenous self-sustaining oscillators, where periodically expressed genes control functions at all levels of biological organization. These mechanisms are detectable from prokaryotes to humans, and their basic molecular components are common in most living organisms. This review focuses on the basic properties of biological circadian clocks and their possible involvement in human diseases.
Asunto(s)
Relojes Biológicos/fisiología , Ritmo Circadiano/fisiología , Animales , HumanosRESUMEN
We describe the complete sequence, genomic organization, and FISH chromosome mapping of the human VAMP2. We identified a 7-kb clone, pISSHG2b3A, containing the entire structure of VAMP2. Previous studies performed by others identified a 5-kb clone, pVPC5-2, containing the incomplete VAMP2. The pVPC5-2 clone was partially sequenced and mapped to the broad region 17pter-->p12 by somatic cell hybridization. Our clone overlaps the pVPC5-2 clone and extends approximately 2 kb at the 3' end. In this study, we mapped this gene more precisely on 17p12 by FISH and we found a new polymorphic microsatellite, (GT)(7)CC(GT)(5), in exon V. This microsatellite, revealing three alleles with frequencies of 0.778, 0.139, and 0.083, might be useful for future linkage studies. Finally, we localized three previously known markers, stSG12859, TIGR-A002F11, and WIAF-1699 (alias stSG4044), in the 3' untranslated region of the gene.
Asunto(s)
Cromosomas Humanos Par 17/genética , Genes/genética , Proteínas de la Membrana/genética , Secuencia de Bases , Mapeo Cromosómico , ADN/química , ADN/genética , Exones , Humanos , Hibridación Fluorescente in Situ , Intrones , Repeticiones de Microsatélite , Datos de Secuencia Molecular , Polimorfismo Genético , Proteínas R-SNARE , Análisis de Secuencia de ADNRESUMEN
Per genes encode components of the circadian clocks controlling metabolic and behavioural rhythms. The human Per1 cDNA, RIGUI, was previously isolated and mapped on chromosome 17p12 (Sun, Z.S., Albrecht, U., Zhuchenko, O., Bailey, J., Eichele, G., Lee, C.C., 1997. RIGUI, a putative mammalian orthologue of the Drosophila period gene. Cell 90, 1003-1011). We have now isolated the entire genomic locus containing the human Per1 gene, in a search for genes associated with CpG-rich sequences. The hPer1 gene spans 15kb of human genomic DNA and is composed of 23 exons, flanked by 5' and 3' regulatory regions. Comparison of the hPer1 genomic clone with the dbEST database revealed homologies with putative alternative transcripts. Functional mapping within the 5' CpG-rich regulatory region enabled us to locate the hPer1 promoter core in a 510bp-long sequence centred around a TATA box, which supports high levels of hPer1 transcription. A second regulatory region was formally identified in intron 1, which appears to exert a negative role in transcriptional control of hPer1. These regions may be differentially involved in tissue-specificity, and/or circadian regulation, of the human hPer1 gene transcription.
Asunto(s)
Genes/genética , Proteínas Nucleares/genética , Regiones Promotoras Genéticas/genética , Células 3T3 , Animales , Secuencia de Bases , Proteínas de Ciclo Celular , Cloranfenicol O-Acetiltransferasa/genética , Cloranfenicol O-Acetiltransferasa/metabolismo , Mapeo Cromosómico , Cromosomas Humanos Par 17/genética , Clonación Molecular , ADN/química , ADN/genética , ADN/aislamiento & purificación , Proteínas de Drosophila , Exones , Humanos , Hibridación Fluorescente in Situ , Intrones , Ratones , Datos de Secuencia Molecular , Proteínas Circadianas Period , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Análisis de Secuencia de ADN , Transcripción GenéticaRESUMEN
Mouse epididymal sperm cells have the spontaneous ability to take up exogenous DNA. A proportion of the sperm-bound DNA is further internalized into sperm nuclei. In this work, we have followed up the fate of the foreign DNA upon internalization into nuclei. We have found that the internalized plasmid DNA becomes tightly associated with the nuclear scaffold, is extensively rearranged, and undergoes recombination with the sperm genomic DNA. Sequence analysis of two randomly selected clones independently recovered by plasmid rescue from pSV2CAT plasmid-challenged sperm cells shows that DNA fragments from the plasmid are integrated into the mouse sperm genome. The sites of integration are identical in both clones, suggesting that these events do not occur randomly, but take place at preferential sites. A topoisomerase II consensus sequence is found adjacent to one end of the integration site, suggesting a possible role of this enzyme in the process of nonhomologous recombination.