Changes in subcellular localization of mtlrRNA outside mitochondria in oogenesis and early embryogenesis of Drosophila melanogaster.

Mitochondrial large ribosomal RNA (mtlrRNA) has been identified as a cytoplasmic factor inducing pole cells in ultraviolet (UV)-sterilized Drosophila embryos. In situ hybridization studies have revealed that mtlrRNA is present outside mitochondria localized on the surface of polar granules during the cleavage stage. In the present study, we describe the developmental changes in extramitochondrial mtlrRNA distribution through early embryogenesis using in situ hybridization at the light and electron microscopic level.

Regional expression of the transcript encoding sterol carrier protein x-related thiolase and its regulation by homeotic genes in the midgut of Drosophila embryos.

We have isolated a gene designated terminal rings in the midgut (trim), which encodes a transcript expressed in the embryonic midgut in a region-specific manner. The 1.4 kb trim transcript is expressed in two discrete regions of the midgut epithelium during late embryogenesis.

Two-step regulation of ecdysone-inducible late puffs in salivary glands of Drosophila melanogaster.

Our previous study showed that some ecdysone-inducible late puffs could also be induced by a mild detergent (digitonin) in Drosophila salivary glands. However, they could only be induced at the stage immediately prior to when developmentally programmed puffing occurred, suggesting that these late puff loci were under two-step regulation. Using an in vitro culture of salivary glands, we have examined whether ecdysone or the protein products of early puff genes participate in either of the two steps of late puff regulation.

A simplified and efficient method for in situ hybridization to whole Drosophila embryos, using electrophoresis for removing non-hybridized probes: (Drosophila/whole mount-in situ hybridization).

We report a simplified and reliable method for non-radioactive in situ hybridization to whole Drosophila embryos. In the previous method (Tautz and Pfeifle, 1989) the post-hybridization wash, or the procedure for washing non-hybridized probe away from embryos depends simply on diffusion. We modified the method with application of electrophoresis to the wash.

Digitonin Activates Different Sets of Puff Loci Depending on Developmental Stages in Drosophila melanogaster Salivary Glands: (salivary gland chromosomes/detergent/gene regulation/ecdysone-inducible puffs/Drosophila melanogaster).

We showed previously that treatment of Drosophila melanogaster salivary glands with a mild detergent, digitonin, induces heat shock puffs and many developmentally regulated puffs. To find if the mechanism underlying the puff induction by digitonin is related to the temporal control of gene expression in salivary glands, we examined effects of digitonin on salivary glands at various puff stages from late third instar larva to white prepupa. The results indicate that (a) all the heat shock puffs are induced by digitonin irrespective of the developmental stage of the treated glands, (b) intermolt and early puff loci are always irresponsive to digitonin, and (c) late puff loci respond to digitonin to form puffs only before the stage of their developmentally programmed puffing.

Nonradioactive In Situ Hybridization Methods for Drosophila Embryos Detecting Signals by Immunogold-Silver or Immunoperoxidase Method for Electron Microscopy: (electron microscopy/pre-embedding/transcripts/Drosophila embryo).

We present details of in situ hybridization methods for electron microscopy applicable for Drosophila embryos. Improvements upon the foregoing methods were made at 1) hybridization and visualization of signals were carried out with whole embryos that were then processed for electron microscopy, and 2) digoxigenin-labeled probes were detected by the immunogold silver enhancement method or by the immunoperoxidase method. Using these methods.

A Mutation in the Drosophila Profilin Homolog Gene Affects Gametogenesis and Bristle Development in Both Sexes: (Drosophila mutant/profilin/gametogenesis/bristle).

We have isolated a Drosophila melanogaster mutant, allelic to the profilin gene reported as chickadee. We named the allele chickadee , in which the oogenesis and the spermatogenesis are disrupted, and the bristles are malformed. In the mutant nurse cells, cytoplasmic actin filaments fail to polymerize, and nuclei are displaced.

Developmentally Regulated Splicing of the Third Intron of P Element in Somatic Tissues in Drosophila Embryos: (transposon/P element/splicing/Drosophila embryo).

In Drosophila, it has been suggested that the third intron of the P element is spliced out only in germ-line cells. However, we found that the splicing took place in some somatic tissues during embryogenesis, as well as in pole cells, progenitor cells of the germ line. To detect the splicing activity in vivo, we designed an assay system to visualize the cells where the third intron was spliced out by the histochemical staining for β-galactosidase activity.

Mutations Affecting Embryonic F-Actin Reorganization also Affect Separation of Nuclei from their Sisters and from the Cortex in Drosophila Cleavage Embryos: (Drosophila/nuclear migration, F-actin, mutants).

We showed in Drosophila that nuclear migration was reduced all through cleavage stages in embryos with any one of the maternal-effect mutations, gs(1)N441 and gs(1)N26, in which F-actin reorganization in cleavage embryos is disordered. Moreover, we determined nuclear positions in embryos at cycle 1 and 2 in the wild type and two mutants, gs(1)N441 and gs(1)N26, in order to test if the nuclear migration is regulated within a nuclear cycle. At cycle 1, there was no difference in nuclear position among the strains that we observed.

Cytoplasmic factors determining anteroposterior polarity in Drosophila embryos.

Cytoplasm removal/transplant techniques applied to Drosophila cleavage-stage embryos induced changes in anteroposterior polarity. Removal of anterior cytoplasm or anterior transplantation of posterior cytoplasm caused the anterior formation of posterior (telson) structures, and the replacement of anterior cytoplasm with posterior cytoplasm induced double-abdomen embryos, as reported by Frohnhöfer et al. [J Embryol Exp Morphol 97 (suppl):169-179 (1986)].

Differences in Fine Structures between Normal and RNA-induced Drosophila Pole Cells: (Drosophila pole cell/fine structure/polar granule/nuclear body/cytoplasmic determinant).

Fine structures were compared between normal pole cells and those induced in embryos that had been uv-irradiated and then injected with intact polar plasm or with poly(A) RNA extracted from cleavage embryos. Nuclei in nomal pole cells were spherical. In contrast, those in the induced pole cells were deformed to variable extents depending on materials injected with.

Activation of Heat-Shock Genes by Digitonin is Selectively Repressed in Preheated Drosophila Salivary Glands: (Drosophila/heat-shock puff/digitonin/gene expression).

Treatment of Drosophila salivary glands with a mild detergent, digitonin, activates puffing at 35 chromosome loci. These digitonin-activated puffs include all of the nine heat-shock puffs known in D. melanogaster.

Accumulation and Spatial Distribution of Poly(A) RNA in Oocytes and Early Embryos of Drosophila melanogaster: (Poly(A) RNA/in situ hybridization/oocytes and embryos/Drosophila melanogaster).

We describe the accumulation and distribution of poly (A) RNA during oogenesis and early embryogenesis as revealed by in situ hybridization with a radio-labeled poly (U) probe. The amount of poly (A) RNA in nurse cell cytoplasm continuously increased untill mid-vitellogenic stage (st. 10), then decreased with the rapid increase of poly (A) RNA in the oocyte (st.

Maternal Messenger RNA as a Determinant of Pole Cell Formation in Drosophila Embryos: (polar plasm/mRNA/cytoplasmic determinant/pole cells/germ cells).

Some polar plasm components are UV-sensitive. Messenger RNA extracted from oocytes or cleavage embryos can to induce pole cells in embryos that have been deprived of ability to form pole cells by UV-irradiation. This article reviews studies on the role of this mRNA in the developmental pathway leading to germ cell formation.

Effects of UV-irradiation at Various Wavelengths on Sterilizing Drosophila Embryos: (Drosophila embryo/UV-effects/pole cells/polar plasm/nucleic acids).

Embryos of Drosophila melanogaster at the early intravitelline nuclear multiplication stage were irradiated with UV light at the posterior pole. The sterility and mortality of these embryos were examined in relation to the dose and wavelength of the UV light. Sterility, expressed either as the frequency of pole-cell-deficient embryos, or as the frequency of agametic adults, was found to be dependent on the wavelength of UV light.

Isolation and characterization ofgrandchildless-like mutants inDrosophila melanogaster.

Two temperature-sensitive sex-linkedgrandchildless (gs)-like mutations (gs(1)N26 andgs(1)N441) were induced by ethylmethane sulphonate inDrosophila melanogaster. They complemented each other and mapped at two different loci (1-33.8±0.

BEHAVIOR OF INTERPHASE EMBRYONIC NUCLEI TRANSPLANTED IN NUCLEAR MULTIPLICATION STAGE EMBRYOS OF DROSOPHILA MELANOGASTER.

Interphase nuclei were transplanted from syncytial blastoderm into early cleavage embryos of Drosophila melanogaster. The transplanted nuclei, when exposed to host cytoplasm, were initiated to mitosis. During the period from 10 to 50 min after transplantation, the implanted nuclei and host nuclei were found not synchronous in their mitotic cycles.