In experiments on mouse and human cells it was demonstrated that rDNA plays an important role in epigenetic regulation of many genes. To identify and study rDNA-contacting genes in Drosophila we used the 4С (circular chromosome conformation capture) approach. We detected very stable contacts of rDNA genes within a 5-kb region inside the Tlk gene residing in X chromosome. This 5-kb region corresponds to small RNAs. After heat shock treatment both the amount of contacts, and the expression level of the gene were increased. Tlk and Rala are genes that share the same short bidirectional promoter but exhibit different expression levels. Around the region of rDNA contacts inside the Tlk gene, looped domains were formed. We conclude that rDNA contact-dependent epigenetic regulation is guided by small RNAs and that the contacts are involved in rearrangements of the looped domains.Boric acid is essential for plants and has many vital roles in animals and microorganisms. However, its high doses are toxic to all organisms. We previously screened yeast deletion collections to identify boric acid-resistant and susceptible mutants to identify genes that play a role in boron tolerance. Here, we analyzed boron resistant mutants (elplΔ, elp3Δ, elp6Δ, ncs2Δ, ncs6Δ and ktil2Δ) for their abilities to modulate the general amino acid control system (GAAC) and to induce boron efflux pump ATR1. The mutants analyzed in this study lack the genes that play roles in tRNA Wobble base modifications. selleck chemicals llc We found that all of the boron resistant mutants activated Gcn4-dependent reporter gene activity and increased the transcript level of the ATR1 gene. Additionally, boron resistant cells accumulated less boric acid in their cytoplasm compared to the wild type cells upon boron exposure. Thus, our findings suggested that loss of wobble base modifications in tRNA leads to GAAC activation and ATR1 induction, which in turn reduced intracellular boron levels and caused boron resistance.Homology-directed (HD) genome modification offers an opportunity to precisely modify the genome. Despite reported successful cases, for many loci, precise genome editing remains challenging and inefficient in vivo. Here we report an effort to precisely knock-in a GFP reporter into gad locus mediated by CRISPR/Cas9 system in the zebrafish Danio rerio. PCR artifact was detected in testing for homologous recombination (HR), but was mitigated by optimizing PCR condition and decreasing the injected targeting plasmid concentration. Under this optimized condition, time course analysis revealed a decline of the HR-positive embryos at embryogenesis progressed. GFP signals also diminished at later developmental stages. The GFP signals were consistent with PCR detection, both of which suggested the loss of targeted insertion events at later stages. Such loss of insertion might be one underlying reason for the inability to obtain germ-line transgenic lines with GFP knocked into the gad locus. Our results suggest that the low HR efficiency associated with CRISPR-mediated knock-in is in part due to loss of insertion after targeted integration into the gad locus.Here we attempt to reconstruct the sequence of events that led to the formation of three regulatory piRNA clusters, namely, 20A, 38C and flamenco in the Drosophila melanogaster genome. Both the 38C and flamenco clusters include inverted sequences, which potentially form double-stranded RNA hairpins. We present evidence in favor of the well-known hypothesis of piRNA clusters as “transposon traps”. According to this model, the presence of the only copy of the transposon in the genome indicates that its expression is suppressed by an RNA-interference mechanism immediately after the mobile element enters the piRNA cluster. We also discuss high the structural variability of piRNAs in Drosophila clusters and cases of horizontal transmobile elements between related species.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.Obesity is one of the major challenges in modern society. More than a third of the world’s population suffers froms overweight. This phenotype affects the quality of life and is associated with cardiovascular diseases, diabetes, cancer and reproductive disorders. The population variability of allele frequencies of 26 single nucleotide polymorphisms, in association with obesity and body mass index, according to data from genome-wide association studies (GWASs) is discussed in this study. Genetic variability was analyzed in populations of Northern Eurasia and populations from the human genome diversity project (HGDP). The population samples are characterized by high genetic diversity that correlates with climatic and geographical parameters. The results of the test for searching for natural selection signals revealed a selection effect for rs1167827 of the HIP1 gene, rs7138803 and rs7164727 located in the intergenic region, rs7141420 of the NRXN3 gene, rs7498665 of the SH2B1 gene, and rs7903146 of the TCF7L2 gene.