A Drosophila melanogaster hobo-white+ vector mediates low frequency gene transfer in D. virilis with full interspecific white+ complementation

Transformation of a Drosophila virilis white mutant host strain was attempted using a hobo vector containing the D. melanogaster mini-white⁺ cassette (H[w⁺, hawN]) and an unmodified or heat shock regulated hobo transposase helper. Two transformant lines were recovered with the unmodified helper (HFL1), one containing only the white⁺ marked vector, and a sibling line containing the vector as well as an HFL1 helper integration. An approximate total transformation frequency of 1% is deduced. A high frequency of wing and eye morphology mutants were also observed, suggesting that hobo may have mobilized a related element in D. virilis. The data reaffirms a relatively low transformation vector activity for the hobo transposon in D. virilis; however, nearly full interspecific expression of the white⁺ marker supports its possible function in other species as well.     

Basolateral junctions are sufficient to suppress epithelial invasion during Drosophila oogenesis.

Epithelial junctions play crucial roles during metazoan evolution and development by facilitating tissue formation, maintenance, and function. Little is known about the role of distinct types of junctions in controlling epithelial transformations leading to invasion of neighboring tissues. Discovering the key junction complexes that control these processes and how they function may also provide mechanistic insight into carcinoma cell invasion. Here, using the Drosophila ovary as a model, we show that four proteins of the basolateral junction (BLJ), Fasciclin-2, Neuroglian, Discs-large, and Lethal-giant-larvae, but not proteins of other epithelial junctions, directly suppress epithelial tumorigenesis and invasion. Remarkably, the expression pattern of Fasciclin-2 predicts which cells will invade. We compared the apicobasal polarity of BLJ tumor cells to border cells (BCs), an epithelium-derived cluster that normally migrates during mid-oogenesis. Both tumor cells and BCs differentiate a lateralized membrane pattern that is necessary but not sufficient for invasion. Independent of lateralization, derepression of motility pathways is also necessary, as indicated by a strong linear correlation between faster BC migration and an increased incidence of tumor invasion. However, without membrane lateralization, derepression of motility pathways is also not sufficient for invasion. Our results demonstrate that spatiotemporal patterns of basolateral junction activity directly suppress epithelial invasion by organizing the cooperative activity of distinct polarity and motility pathways.     

Pattern of spatial distribution inDrosophila melanogaster

The effect of temperature and sex on spatial distribution ofDrosophila melanogaster adults was studied in a specially designed apparatus. It was observed that individuals tend to aggregate in sections of the sphere independently of sex and temperature. Nevertheless, decrease in temperature increase aggregation. The mobility of both males and females indicates a megative geotactic tendency.     

Amide molecular clocks in drosophila proteins: potential regulators of aging and other processes

After synthesis and folding, peptides and proteins undergo changes in charge and conformation through nonenzymatic deamidation of asparaginyl and glutaminyl residues. Each amide has a specific deamidation rate that is genetically determined by the sequence of residues immediately adjacent in the peptide chain and by secondary, tertiary, and quaternary structure. By means of experimentally verified computations, we have determined the deamidation rates of 49 Drosophila peptides and proteins. These rates demonstrate that deamidation provides molecular clocks that are suitable for the regulation of Drosophila aging, development, and other biochemical processes. We have also determined the rates of deamidation for 17,886 other proteins from a wide variety of organisms. The distribution function of these deamidation rates demonstrates the suitability of amide residues as biomolecular clocks.     

BicD-dependent localization processes: from Drosophilia development to human cell biology

Many eukaryotic cells depend on proper cell polarization for their development and physiological function. The establishment of these polarities often involve the subcellular localization of a specific subset of proteins, RNAs and organelles. In Drosophila, the microtubule-dependent BicD (BicaudalD) localization machinery is involved in the proper localization of mRNA during oogenesis and embryogenesis and the proper positioning of the oocyte and photoreceptor nuclei. BicD acts together with the minus-end directed motor dynein as well as Egl and Lis-1. The finding that the mammalian homologs of BicD function in retrograde Golgi-to-ER transport has supported the view that BicD may be part of a repeatedly used and evolutionary conserved localization machinery. In this review we focus on the various processes in which BicD is involved during Drosophilian development and in mammals. In addition, we evaluate the interactions between BicD, the dynein localization machinery and associated factors.     

Selection for high and low mating propensity inDrosophila ananassae

InDrosophila ananassae, artificial selection was carried out for high and low mating propensity for 15 generations. Response to selection was from about F₅, with rapid divergence in mating frequencies in replicates of both fast and slow lines. To assess the effect of selection on the two sexes, females and males of the selected lines were tested against their respective counterparts of the control line after 15 generations. Significant differences in mating propensity were observed when selected males were tested against the control females, which suggests that males were much more affected by selection than females. After 15 generations the fast and slow lines (both replicates) were crossedinter se and mating frequencies of F₁ hybrids were studied in the same way as during the selection experiment. F₁ flies had a higher mating activity compared to their parental lines when males were derived from fast lines to produce hybrids. On the other hand, F₁ hybrids produced by crossing slow-line males with fast-line females showed mating frequencies similar to those of the slow parental lines. These findings suggest that mating propensity inD. ananassae is under the control of polygenes. Furthermore, the significant differences in mating propensity of hybrids produced by the fast and slow males indicate the possibility of a Y-linked influence on mating propensity inD. ananassae.The present investigation was carried out during the tenure of a senior research fellowship of the CSIR, New delhi, to S.C.     

Mutations in raised Drosophila melanogaster affect experience-dependent aspects of sexual behavior in both sexes

Many aspects of the reproductive behavior of Drosophila melanogaster are modified dramatically by experience and age. Males' courtship of immature males and fertilized females decreases over time. Females' receptivity to copulation, and the behaviors that females perform and elicit, are affected by their age and sexual experience. We show that mutations in a raised stock affect all of these age- and experience-dependent aspects of male and female sexual behavior. Experience has no effect on raised males' courtship of immature males and has opposite effects on raised and wild-type males' courtship of fertilized females. In comparison to controls, raised females become sexually mature at an earlier age, and sexually mature raised virgin females copulate more quickly. Following mating, raised females elicit more courtship and remate faster and more frequently than control females.