Essential functions of RNA helicase Vasa in maintaining germline stem cells and piRNA-guided silencing in spermatogenesis.

DEAD-box RNA helicase Vasa is required for gonad development and fertility in multiple animals. Vasa is implicated in many crucial aspects of oogenesis, including translation regulation, primordial germ cell specification, piRNA silencing of transposable elements, and maintenance of germline stem cells (GSCs). However, data about Vasa functions in spermatogenesis remain controversial.

Molecular Insights into Female Hybrid Sterility in Interspecific Crosses between and .

Species of the genus have served as favorite models in speciation studies; however, genetic factors of interspecific reproductive incompatibility are under-investigated. Here, we performed an analysis of hybrid female sterility by crossing females and males. Using transcriptomic data analysis and molecular, cellular, and genetic approaches, we analyzed differential gene expression, transposable element (TE) activity, piRNA biogenesis, and functional defects of oogenesis in hybrids.

Comparative transcriptional analysis uncovers molecular processes in early and mature somatic cyst cells of Drosophila testes.

The tight interaction between somatic and germline cells is conserved in animal spermatogenesis. The testes of Drosophila melanogaster are the model of choice to identify processes responsible for mature gamete production. However, processes of differentiation and soma-germline interactions occurring in somatic cyst cells are currently understudied.

as a Model System for Studying of the Evolution and Functional Specialization of the Y Chromosome.

The Y chromosome is one of the sex chromosomes found in males of animals of different taxa, including insects and mammals. Among all chromosomes, the Y chromosome is characterized by a unique chromatin landscape undergoing dynamic evolutionary change. Being entirely heterochromatic, the Y chromosome as a rule preserves few functional genes, but is enriched in tandem repeats and transposons.

piRNA-mediated gene regulation and adaptation to sex-specific transposon expression in male germline.

Small noncoding piRNAs act as sequence-specific guides to repress complementary targets in Metazoa. Prior studies in ovaries have demonstrated the function of the piRNA pathway in transposon silencing and therefore genome defense. However, the ability of the piRNA program to respond to different transposon landscapes and the role of piRNAs in regulating host gene expression remain poorly understood.

Genes and the piRNA Pathway in Speciation and Reproductive Isolation of .

One of the main conditions of the species splitting from a common precursor lineage is the prevention of a gene flow between diverging populations. The study of interspecific hybrids allows to reconstruct the speciation mechanisms and to identify hybrid incompatibility factors that maintain post-zygotic reproductive isolation between closely related species. The regulation, evolution, and maintenance of the testis-specific genetic system in is the subject of investigation worldwide.

Functional Significance of Satellite DNAs: Insights From .

Since their discovery more than 60 years ago, satellite repeats are still one of the most enigmatic parts of eukaryotic genomes. Being non-coding DNA, satellites were earlier considered to be non-functional "junk," but recently this concept has been extensively revised. Satellite DNA contributes to the essential processes of formation of crucial chromosome structures, heterochromatin establishment, dosage compensation, reproductive isolation, genome stability and development.

piRNA silencing contributes to interspecies hybrid sterility and reproductive isolation in Drosophila melanogaster.

The piRNA pathway is an adaptive mechanism that maintains genome stability by repression of selfish genomic elements. In the male germline of Drosophila melanogaster repression of Stellate genes by piRNAs generated from Supressor of Stellate (Su(Ste)) locus is required for male fertility, but both Su(Ste) piRNAs and their targets are absent in other Drosophila species. We found that D.