Two single-headed myosin V motors bound to a tetrameric adapter protein form a processive complex

The yeast class V myosin Myo4p moves processively in vivo in a cargo-dependent manner following formation of a double-headed complex with the adapter protein She3p and the mRNA-binding protein She2p

Principles of mRNA transport in yeast

mRNA localization and localized translation is a common mechanism by which cellular asymmetry is achieved. In higher eukaryotes the mRNA transport machinery is required for such diverse processes as stem cell division and neuronal plasticity. Because mRNA localization in metazoans is highly complex, studies at the molecular level have proven to be cumbersome. However, active mRNA transport has also been reported in fungi including Saccharomyces cerevisiae, Ustilago maydis and Candida albicans, in which these events are less difficult to study. Amongst them, budding yeast S. cerevisiae has yielded mechanistic insights that exceed our understanding of other mRNA localization events to date. In contrast to most reviews, we refrain here from summarizing mRNA localization events from different organisms. Instead we give an in-depth account of ASH1 mRNA localization in budding yeast. This approach is particularly suited to providing a more holistic view of the interconnection between the individual steps of mRNA localization, from transcriptional events to cytoplasmic mRNA transport and localized translation. Because of our advanced mechanistic understanding of mRNA localization in yeast, the present review may also be informative for scientists working, for example, on mRNA localization in embryogenesis or in neurons

Application of the bacteriophage Mu-driven system for the integration/amplification of target genes in the chromosomes of engineered Gram-negative bacteria—mini review

The advantages of phage Mu transposition-based systems for the chromosomal editing of plasmid-less strains are reviewed. The cis and trans requirements for Mu phage-mediated transposition, which include the L/R ends of the Mu DNA, the transposition factors MuA and MuB, and the cis/trans functioning of the E element as an enhancer, are presented. Mini-Mu(LR)/(LER) units are Mu derivatives that lack most of the Mu genes but contain the L/R ends or a properly arranged E element in cis to the L/R ends. The dual-component system, which consists of an integrative plasmid with a mini-Mu and an easily eliminated helper plasmid encoding inducible transposition factors, is described in detail as a tool for the integration/amplification of recombinant DNAs. This chromosomal editing method is based on replicative transposition through the formation of a cointegrate that can be resolved in a recombination-dependent manner. (E-plus)- or (E-minus)-helpers that differ in the presence of the trans-acting E element are used to achieve the proper mini-Mu transposition intensity. The systems that have been developed for the construction of stably maintained mini-Mu multi-integrant strains of Escherichia coli and Methylophilus methylotrophus are described. A novel integration/amplification/fixation strategy is proposed for consecutive independent replicative transpositions of different mini-Mu(LER) units with “excisable” E elements in methylotrophic cells

About Formation of a Water Drainage System on the Territories under Development

The trend of widespread destruction of forest plantations, especially in the forest-steppe and steppe regions, such as the Orenburg region, leads to the depletion of water resources due to an increase of flow nonuniformity. Simultaneously, the strengthened negative geodynamic processes lead to flooding and waterlogging of large areas. A widespread afforestation and run-off regulation by working out the reasonable hydro construction program including the effective water conservation measures were suggested for reducing the intensity of negative geodynamic processes and mitigating the catastrophic consequences

Drosophila melanogaster inhabiting northern regions of European Russia are infected with Wolbachia which adversely affects their life span

Wolbachia is a genus of bacteria causing intracellular infection in the natural populations of Drosophila melanogaster on all continents. In D. melanogaster, Wolbachia affects various life history traits, behaviour, sensitivity to stress and viral infection. The phenotypic effects of Wolbachia might evolve to promote its further spreading, increasing the interest in exploring the spread of Wolbachia, in particular, at the boundar­ies of the D. melanogaster habitat, in association with the effects on vital traits of host species. In this paper, we present data on the level of Wolbachia infection in two D. melanogaster populations from the northern regions of European Russia: Alexandrov (56.41° N, 38.72° E) and Valday (58.02° N, 33.24° E). The flies were collected in private apple gardens located in two small hamlets without supermarkets or fruit markets, from 2010 to 2015. The both populations demonstrated the same level of infection: in average, 69.7 % of the inbred lines (ILs) obtained from single females of the Alexan­drov population and 68.4 % of ILs obtained from single females of the Valday population. The infection rate varied from year to year showing a tendency to reduc­tion, its overall level being within the range previously observed in other habitats. Life spans were compared in sub-lines of the same IL, one infected with Wolbachia and the other treated with tetracycline healing this infection. In four out of five ILs, the lifespan of both males and females was severely affected by Wolbachia; in different ILs, the mean life spans reduced from 1.8 to 5.4 times and from 1.4 to 2.4 times, respectively. Our results confirm that, despite D. melanogaster widespread distribution, the Wolbachia effect on their life span has been mostly negative

Crystal structure of apo-calmodulin bound to the first two IQ motifs of myosin V reveals essential recognition features

A 2.5-Å resolution structure of calcium-free calmodulin (CaM) bound to the first two IQ motifs of the murine myosin V heavy chain reveals an unusual CaM conformation. The C-terminal lobe of each CaM adopts a semi-open conformation that grips the first part of the IQ motif (IQxxxR), whereas the N-terminal lobe adopts a closed conformation that interacts more weakly with the second part of the motif (GxxxR). Variable residues in the IQ motif play a critical role in determining the precise structure of the bound CaM, such that even the consensus residues of different motifs show unique interactions with CaM. This complex serves as a model for the lever arm region of many classes of unconventional myosins, as well as other IQ motif-containing proteins such as neuromodulin and IQGAPs

The Myosin IXb Motor Activity Targets the Myosin IXb RhoGAP Domain as Cargo to Sites of Actin Polymerization

Myosin IXb (Myo9b) is a single-headed processive myosin that exhibits Rho GTPase-activating protein (RhoGAP) activity in its tail region. Using live cell imaging, we determined that Myo9b is recruited to extending lamellipodia, ruffles, and filopodia, the regions of active actin polymerization. A functional motor domain was both necessary and sufficient for targeting Myo9b to these regions. The head domains of class IX myosins comprise a large insertion in loop2. Deletion of the large Myo9b head loop 2 insertion abrogated the enrichment in extending lamellipodia and ruffles, but enhanced significantly the enrichment at the tips of filopodia and retraction fibers. The enrichment in the tips of filopodia and retraction fibers depended on four lysine residues C-terminal to the loop 2 insertion and the tail region. Fluorescence recovery after photobleaching and photoactivation experiments in lamellipodia revealed that the dynamics of Myo9b was comparable to that of actin. The exchange rates depended on the Myo9b motor region and motor activity, and they were also dependent on the turnover of F-actin. These results demonstrate that Myo9b functions as a motorized RhoGAP molecule in regions of actin polymerization and identify Myo9b head sequences important for in vivo motor properties