Activation of local translation in neurites in response to stimulation is an important step in the formation of long-term memory (LTM). CPEB proteins are a family of translation factors involved in LTM formation. The Drosophila CPEB protein Orb2 plays an important role in the development and function of the nervous system. Mutations of the coding region of the orb2 gene have previously been shown to impair LTM formation. We found that a deletion of the 3’UTR of the orb2 gene similarly results in loss of LTM in Drosophila. As a result of the deletion, the content of the Orb2 protein remained the same in the neuron soma, but significantly decreased in synapses. Using RNA immunoprecipitation followed by high-throughput sequencing, we detected more than 6000 potential Orb2 mRNA targets expressed in the Drosophila brain. Importantly, deletion of the 3′UTR of orb2 mRNA also affected the localization of the Csp, Pyd, and Eya proteins, which are encoded by putative mRNA targets of Orb2. Therefore, the 3′UTR of the orb2 mRNA is important for the proper localization of Orb2 and other proteins in synapses of neurons and the brain as a whole, providing a molecular basis for LTM formation.

The variability of three single nucleotide polymorphism (SNP) loci in the mitochondrial DNA (mtSNP) is analyzed for sockeye salmon populations over a major part of the species range, from Chukotka to the Kuril Islands. Two basic mtSNP haplotypes, GCC and GTT, have been revealed in 20 sockeye samples from 15 lake–river systems on the Asian coast of the Pacific Ocean. In most of the samples, the ratio of the haplotypes is approximately equal. The GTT haplotype dominates the populations from the Kuril Islands (except Shumshu Island); only the GCC haplotype has been found in the sample from the Commander Islands. This geographic pattern of haplotype distribution was presumably caused by the historico-demographic events related to the formation of the Asian sockeye range in the Middle–Late Pleistocene, viz., fragmentation of the species range and subsequent secondary contact between previously diverged populations. These data provide a basis to consider different scenarios for the formation of the modern diversity of sockeye mtSNP haplotypes, all of which suggest multiple expansions of the species to Asian waters during the periods of oceanic transgression after the Pleistocene glaciations.

Multipotent mesenchymal stem/stromal cells (MSC) are one of the crucial regulators of regeneration and tissue repair and possess an intrinsic program from self-organization mediated by condensation, migration and self-patterning. The ability to self-organize has been successfully exploited in tissue engineering approaches using cell sheets (CS) and their modifications. In this study, we used CS as a model of human MSC spontaneous self-organization to demonstrate its structural, transcriptomic impact and multipotent stromal cell commitment. We used CS formation to visualize MSC self-organization and evaluated the role of the Rho-GTPase pathway in spontaneous condensation, resulting in a significant anisotropy of the cell density within the construct. Differentiation assays were carried out using conventional protocols, and microdissection and RNA-sequencing were applied to establish putative targets behind the observed phenomena. The differentiation of MSC to bone and cartilage, but not to adipocytes in CS, occurred more effectively than in the monolayer. RNA-sequencing indicated transcriptional shifts involving the activation of the Rho-GTPase pathway and repression of SREBP, which was concordant with the lack of adipogenesis in CS. Eventually, we used an inhibitory analysis to validate our findings and suggested a model where the self-organization of MSC defined their commitment and cell fate via ROCK1/2 and SREBP as major effectors under the putative switching control of AMP kinase.

The variability of 45 single nucleotide polymorphism (SNP) loci was studied in nine samples of the sockeye salmon Oncorhynchus nerkafrom the rivers of southwestern Kamchatka. The Wahlund effect,...

The morphological and genetic heterogeneity of sockeye salmon Oncorhynchus nerka (from both the mixed samples and the samples collected in different periods of its mass migration) catched in the mouths of the rivers of west (Ozernaya, Bolshaya, and Palana rivers) and east (Kamchatka River) costs of Kamchatka Peninsula has been analyzed. The stocks of the sockeye salmon inhabiting these river basins (including tributaries and lakes) are the largest in Asia. According to the assessment of the biological parameters and the allele frequencies at 45 loci of single-nucleotide polymorphism at the DNA level, no periodicity in the mass-spawning migration of the sockeye salmon in the rivers of the Kamchatka Peninsula’s western coast was revealed. The analysis of the sockeye salmon’s mixed samples collected from the western Kamchatka Peninsula rivers allowed identifying a group of fishes in the sample taken from the Bolshaya River that was ascertained to the lake form. With respect to the Ozernaya and Palana river samples, the phenotypic and genetic heterogeneity was not revealed. The heterogeneity revealed in the fish sample taken from the Kamchatka River’s mouth can point to a complex spatial-genetic structure of the sockeye salmon in the basin of this lake–river system. The differences between the samples collected during the mass migration through the river’s mainstream indicate the successive approach of fishes to the mouth by the local groups that spawn in the different parts of the river basin.