RESUMEN
RNA preparations synthesized in vitro were used to study the influence of RNA interference on the Kruppel gene activity in Drosophila embryos. RNA complementary in parallel orientation to the mRNA fragment proved to induce the development of Kruppel phenocopies. The data obtained indicate that mechanisms of specific regulation of gene activity exist in Drosophila cells, which are sensitive to the formation of both parallel and antiparallel RNA-RNA duplexes that include mRNA of the corresponding gene.
Asunto(s)
Drosophila/genética , Genes Homeobox , Fenotipo , ARN Complementario/genética , ARN Mensajero/genética , Animales , Drosophila/embriología , Embrión no Mamífero , MicroinyeccionesRESUMEN
Data on molecular analysis of the insertion sites of nine random copies of burdock retrotransposon are presented. The 12-bp consensus sequence of the insertion sites, YNNUTUTUYAYA (Y-pyrimidine; U-purine), was determined. Homology between the burdock sequence and ribosomal genes was revealed. Three copies of this element were located within the region of ribosomal repeats: one copy in the 18S RNA gene, and two copies in the same intergenic spacer region, in the so-called Alu-repeats of Drosophila, in different copies of ribosomal genes.
Asunto(s)
Drosophila/genética , Retroelementos , Animales , Secuencia de Bases , ADN , Datos de Secuencia Molecular , ARN Ribosómico 18S/genética , Secuencias Repetitivas de Ácidos Nucleicos , Homología de Secuencia de Ácido NucleicoRESUMEN
In analysis of instability at loci yellow and scute, induced by introduction of the active P-element transposase into the genome of line y2nsscme, alleles of these loci with transposase-independent instability were selected. The mutation rate of these alleles reached tens of percent. Two types of transposase-independent instability were described: (1) instability limited to the scute locus and (2) instability at both yellow and scute loci.
Asunto(s)
Mapeo Cromosómico , Elementos Transponibles de ADN , Proteínas de Drosophila , Drosophila melanogaster/genética , Alelos , Animales , Proteínas de Unión al ADN/genética , Femenino , Hormonas de Insectos/genética , Masculino , Nucleotidiltransferasas/metabolismo , Factores de Transcripción/genética , TransposasasRESUMEN
Main features of mutagenesis induced in the double super-unstable system in Drosophila melanogaster males and females was studied earlier. Very different y- and sc-alleles arose under the mutagenesis. These are differed one from another by the expression of yellow and scute loci. However, it was shown that the female's mutagenesis very differed from the male's one. The structure of a homologous chromosome has played an important role in the mutagenesis in Drosophila females. We found here that the homologous translocation in Y chromosome led to double decrease of the frequency of the mutagenesis in males. It is proposed that interconnections between two homologous insertions are essential in the recombinational processes by which alleles change. The nature and mechanism of the sub-lethal allele's formation in the presence of translocation in Y chromosome is discussed.
Asunto(s)
Mapeo Cromosómico , Drosophila melanogaster/genética , Mutagénesis , Translocación Genética , Cromosoma Y , Animales , MasculinoRESUMEN
The dynamics of life span (LS) have been studied in successive generations of postirradiation and control groups of Drosophila melanogaster, strain D-32, after a single exposure to Co60 gamma-quantum irradiation. It has been shown using mathematical procedures that in all postirradiation generations, with one exception, survival curves retain their canonical shape. This is indicative of the unchangeable nature of LS distribution. The mean LS of the progeny of irradiated parents either coincides with control values or can be higher or lower. Moreover, single irradiation results in an altered time-scanning of LS variations in successive generations as compared with controls. The possible origin of LS instability is discussed.
Asunto(s)
Longevidad/efectos de la radiación , Animales , Drosophila melanogaster , Femenino , Rayos gamma/efectos adversos , Masculino , Factores Sexuales , Análisis de SupervivenciaRESUMEN
The dynamics of life span (LS) and fecundity in Drosophila melanogaster, strain D-32, were analyzed in a series of successive generations. Highly reliable variations in both fitness components were found. On initial inspection the variations would be characterized as random or irregular wherein mean values differed up to threefold. The variance in longevity is greater in females than in males. By use of mathematical procedures we have shown a scale regularity in LS distributions for all generations. Such regularity, in spite of considerable differences in absolute values (mean and maximum LS), suggested that the origin of LS instability is nonrandom.
Asunto(s)
Drosophila melanogaster/fisiología , Longevidad , Animales , Femenino , Fertilidad , Masculino , Mortalidad , Factores Sexuales , Análisis de SupervivenciaRESUMEN
The influence of meiotic mutations on the mutation changes in the double super-unstable system in the yellow and scute loci of Drosophila melanogaster was studied. The mei-41D5 and mei-218 mutations changed the spectrum and frequency of mutagenesis in males of the y2nsscme strain, in contrast to the postulate that meiotic mutations do not interfere with male recombination in D. melanogaster. These mutations also changed the frequency and spectrum of mutagenesis in females. In particular, they inhibited mutagenesis at early stages of ovogenesis. Meiotic conversion did not change specifically by mei mutations. At the same time, the mei-41D5 mutation increased all recombination processes in meiosis. The results obtained indicated the involvement of genetic recombination in mutation changes occurring in the double super-unstable system. Therefore, the latter may be successfully used in studies of the role of different genes and their products in recombination.
Asunto(s)
Mapeo Cromosómico , Drosophila melanogaster/genética , Meiosis/genética , Mutagénesis/genética , Recombinación Genética/genética , Animales , Femenino , Masculino , Mutación/genéticaRESUMEN
We have characterized the phenomenon of super-unstability in yellow and scute loci of Drosophila melanogaster. A few derivatives with different combinations of yellow and scute phenotypes appeared after dysgenic cross between potentially super-unstable stock y2nsscme and P[ry+, (delta 2-3)] (99B). Essentially, the double alterations of yellow and scute phenotypes constitute more than 40% of all derivatives. Most frequently the mutations in both yellow and scute loci change coordinately giving rise to the y+nssc+ allele. Lethal derivatives were not observed. The spectrum and the frequency of the y2nsscme mutagenesis in females differ considerably from the analogous in males. Possibly, the neutral homologous chromosome in females changes contacts between two insertions, and because of that mutagenesis changes too. Thus, all alterations in the double super-unstable system seem to be connected with the recombination between two unstable insertions A genetic exchange may by initiated by a double-strand breaks induced by the transposase of the ends of insertions.