RESUMO
Regulation of retrotransposon activity in somatic tissues is a complex mechanism that has still not been studied in detail. It is strongly believed that siRNA interference is main mechanism of retrotransposon activity regulation outside the gonads, but recently was demonstrated that piRNA interference participates in retrotransposon repression during somatic tissue development. In this work, using RT-PCR, we demonstrated that during ontogenesis piRNA interference determinates retrotransposon expression level on imago stage and retrotransposons demonstrate tissue-specific expression. The major factor of retrotransposon tissue-specific expression is presence of transcription factor binding sites in their regulatory regions.
Assuntos
Drosophila melanogaster , RNA Interferente Pequeno , Retroelementos , Animais , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Retroelementos/genética , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Especificidade de Órgãos , Sítios de Ligação , Interferência de RNARESUMO
The flamenco locus is one of the main components of the piRNA pathway of regulation of mobile genetic elements (MGEs) in Drosophila melanogaster. Mutations at this locus lead to an increase in the transposition activity of MGEs and, as a result, to genetic instability. In this paper, the fertility of a genetically unstable MS strain obtained more than 25 years ago and characterized by a mutation in the flamenco locus and the presence of a functionally active copy of gypsy retrotransposon was investigated. Complex violations of the ovarian morphology were revealed in the MS strain in females: defects in the follicular layer and ring channels, as well as degradation of trophocytes, which in turn led to a decrease in reproductive abilities. Analysis of the MS strain transcriptome showed a decrease in the expression level of 40 genes encoding chorionic proteins and expression specificity at different stages of follicle development. In the F1 and F2 hybrid females from the crosses of MS females with wild type males, restoration of reproductive abilities was observed, despite the fact that half of the F2 females had the flamenco genotype and genetic instability caused by transposition of gypsy (according to the ovo^(D) test). Moreover, the frequency of gypsy transposition in the hybrid F2 females with the flamenco genotype doubled in comparison with the MS strain females. Thus, the MS strain had acquired partial suppression of the flamenco phenotype and accumulated several recessive mutations in the genes that control oogenesis after cultivation for over 25 years.
Assuntos
Elementos de DNA Transponíveis , Drosophila melanogaster , Retroelementos , Animais , Drosophila melanogaster/genética , Drosophila melanogaster/fisiologia , Feminino , Fertilidade , Genótipo , Masculino , Mutação , Ovário/patologia , FenótipoRESUMO
Results of expression analysis of transcription of the flamenco locus that controls transposition of the mobile genetic element gypsy, RNA interference system genes ago3, zuc, aub, and HP1 heterochromatin protein family genes hp1a, hp1b, hp1c, hp1d (rhino), and hp1e in D. melanogaster SS strain mutant on the flamenco gene are presented. We show that the number of transcripts in the SS strain that are formed in the flamenco locus is unchanged in some freely chosen points, and this is different from the wild-type strain where a decreased number of transcripts is observed, which clearly is a result of processing of the flamenco locus primary transcript, a predecessor of piRNA. At the same time, expression of genes of the RNA interference system is not affected, but there is a reduced level of hp1d gene expression in ovary tissue. We suggest that the hp1d gene product is directly or indirectly involved in the flamenco locus primary transcript processing.
