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At least 739 records · Page 41Linked to original sources
PubMed2000

Isolation of larval behavioral mutants in Drosophila melanogaster.

Genetic loci that influence behavior are often difficult to identify and localize in part due to the quantitative nature of behavioral phenotypes. Previous studies had found an association between pupal lethality and altered larval behavior for mutants of several genes. To facilitate the identification and localization of new mutants that influence larval foraging (movement in the presence of food) and general locomotion (movement in the absence of food) behaviors we identified and then screened a collection of strains carrying pupal-lethal mutations for alterations in these larval behaviors. When the lethal mutation segregated with the behavioral alteration this permitted the mapping of the behavioral locus. Nine new loci on the second chromosome were found to affect larval behavior. Of these, seven loci affected foraging and two affected locomotion. Analyses of these new loci will lead to further understanding of the mechanistic bases of larval behavior.

Analysis of Variance↗
PubMed1995

Distinct mechanisms of action of the Lozenge locus in Drosophila eye and antennal development are suggested by the analysis of dominant enhancers.

The development of the olfactory sense organs on the antenna of the fruit fly Drosophila utilises mechanisms distinct from those used in the rest of the adult peripheral nervous system. Lozenge (lz) is the only locus hither-to identified as required for the development of antennal sense organs. In addition to effects on the antenna, mutations in lz also affect the development of the eye and maxillary palp. We have used the readily-scored eye-phenotype in a temperature sensitive lz allele to screen for dominant modifiers of phenotypes at this locus. We analyse the phenotypes of both intragenic and extragenic modifiers. Our results reinforce the view from developmental studies that lz functions in eye and antennal development in distinct ways.

Alleles↗
PubMed1995

Behavioral and pheromonal phenotypes associated with expression of loss-of-function mutations in the sex-lethal gene of Drosophila melanogaster.

We have shown that female-specific functions of the sex determination gene Sex-lethal (Sxl) regulate sexual behavior and synthesis of the three major sex pheromones that have been identified in normal, sexually mature Drosophilia melanogaster males and virgin females. Diplo-X flies, heterozygous in trans for two partial loss-of-function Sxl mutations, elicit less courtship than normal females and produce large quantities of the inhibitory pheromones that normal males synthesize. In addition, the mutant flies fail to synthesize the female-predominant aphrodisiac pheromone or make very small quantities of this compound.

Animals↗
PubMed2025

The Complete Genome of Three At-Risk Florida Butterflies: Cyclargus thomasi bethunebakeri, Eumaeus atala and Heraclides ponceana.

We present short-read genome assemblies of three butterfly species native to the state of Florida: the Atala butterfly (Eumaeus atala), the Miami blue (Cyclargus thomasi bethunebakeri), and the Schaus' swallowtail (Heraclides ponceana). All species are of conservation concern with the latter two listed as federally endangered. Genome assemblies recovered 77-92% of single-copy orthologous insect genes, providing a valuable resource for advancing lepidopteran genomic research.

Journal Article↗
PubMed1999

Drosophila presenilin is required for neuronal differentiation and affects notch subcellular localization and signaling.

Presenilins are a highly conserved family of proteins first identified as causative genes in early onset familial Alzheimer's disease. Recent studies have suggested a role for presenilins in the Notch-signaling pathway, but their specific function within this pathway remains unclear. Here, we have characterized the Drosophila presenilin gene and protein and studied their interaction with Notch in both mutants and transgenics. We find that the Drosophila presenilin protein is proteolytically cleaved and broadly expressed during development with the highest levels in neurons within the larval CNS. We also show that mutations in Drosophila presenilin (Dps) genetically interact with Notch and result in an early pupal-lethal phenotype characterized by defects in eye and wing development and incomplete neuronal differentiation within the larval CNS. Moreover, we find that processing of Notch in the Golgi by the furin protease is unaffected in Dps mutants and that Notch is present and may even accumulate on the plasma membrane of neuroblasts in the larval CNS of Dps mutants. In contrast, overexpression of Dps in transgenics causes Notch to accumulate in the cytoplasm. Taken together, these results indicate that Drosophila presenilin is required for proper neuronal differentiation and may regulate the subcellular localization of Notch proteins within cells, necessary for their accumulation and subsequent signaling capabilities.

Animals↗
PubMed1999

[Analysis of the interaction of mutations at the Drosophila melanogaster Su(mg), mod(mdg4), and su(Hw) loci].

The mod(mdg4)1u1 mutation modifies the phenotypic expression of mutations induced by the MDG4 insertion. The Suppressor of modifier mdg4 (Su(mg)) gene family was described earlier. Most Su(mg) mutations completely suppressed the negative effect of the mod(mdg4)1u1 mutation on transcription of the yellow gene. However, only a few Su(mg) mutations suppressed the inhibiting effect of mod(mdg4)1u1 on transvection between the y59b/y2 alleles. The interaction of the mod(mdg4) and Su(mg) mutations with the su(Hw) mutation was studied. The phenotypic expression of the Su(mg) and mod(mdg4)1u1 mutations was shown to depend on the presence of the functional protein su(Hw).

Alleles↗
PubMed1999

An element with palindromic structure is required for the expression of TBP (TATA box-binding protein) gene in Drosophila melanogaster.

Previously we showed that the 5'-flanking regions between -261 and -207 of the Drosophila melanogaster TBP (TATA box binding protein) gene is important for its expression. We further made serial deletion mutants in this region and analyzed their promoter activities using the transient transfection assay. We found that the 16 bp deletion from -261 to -245 greatly reduces the promoter activity of the Drosophila TBP gene. The 16 bp DNA element contains half of a 11 bp long palindromic sequence, CTTTT-GAAAAG. Disruption of the palindromic sequence by site-directed mutagenesis severely affected promoter activity. In addition, the electrophoretic mobility shift assay showed that the oligonucleotide containing the palindromic sequence can make specific DNA/protein complexes when it was mixed with the Drosophila nuclear extract, suggesting that it interacts with nuclear protein(s). Our data suggest that the palindromic sequence has a critical role in the expression of the Drosophila TBP gene.

Animals↗
PubMed2000

[The level of dysgenic sterility and recessive mutations induced in laboratory strains of Drosophila melanogaster exposed to chronic low-dose gamma irradiation].

Recent investigations showed that genetic instability accounts for many radiobiological effects. However, mechanisms underlying this phenomenon are still poorly understood. Assuming that mobile genetic elements may be involved in the induction of genetic instability, we studied parameters that characterize the activity of these elements in Drosophila melanogaster: hybrid dysgenesis and the level of recessive lethal mutations. In our experiments, we used D. melanogaster strains that differed in the type of hybrid dysgenesis (P-M and H-E). It was demonstrated that chronic exposure to radiation leads to substantial changes in the genetic structure of a population and an enhanced level of dysgenic sterility. Our results indicate that genetic instability and adaptation to the effect of chronic gamma-radiation are associated with the radiation-induced mobilization of mobile genetic elements.

Animals↗
PubMed2001

[Inhibition of gene expression by administration of homologous double-stranded RNA in Drosophila melanogaster cell culture].

Specific inhibition of gene expression by exogenous homologous double-stranded RNA (dsRNA) in invertebrates and in the early development of vertebrates is termed RNA interference. Cultured cells were cotransfected with reporter plasmids and dsRNA. The inhibitor effect on reporter gene expression depended on the extent of homology between dsRNA and the target gene. RNA interference was also studied in cells cotransfected with plasmids directing synthesis of sense and antisense RNAs. Production of antisense RNA only slightly inhibited expression of the reporter gene. Simultaneous expression of both sense and antisense RNAs from a special plasmid did not inhibit expression of the reporter construct.

Animals↗
PubMed2001

[Drosophila gene rad201 controls cell cycle arrest in irradiated cells].

Mitotic activity of larval neuroblasts was studied in the wild-type Oregon R and mutant rad201G1 and mei-41D5 Drosophila melanogaster at different intervals after gamma-irradiation at a dose of 6 Gy. The data obtained suggest that the rad201 gene is involved in the control of the cell cycle.

Animals↗
PubMed2001

Combinatorial transcriptional regulation: the interaction of transcription factors and cell signaling molecules with homeodomain proteins in Drosophila development.

Patterning and cell fate specification during development require complex interplay among multiple families of transcription factors to establish, maintain, and coordinate transcriptional cascades. During these processes, homeodomain proteins and cell signaling proteins cooperate to generate tissue-and stage-specific responses. This review of physical and genetic interactions in Drosophila melanogaster development highlights the cross-talk among these protein families. Protein-protein association can modulate regulation by both signal transduction-regulated transcription factors and homeodomain proteins, as observed in Drosophila and other organisms. Enhancers or genes regulated by multiple transcription factors provide opportunities for protein-protein binding to modulate transcription factor function. Combinatorial regulation of several enhancers by homeodomain proteins and cell signaling-regulated transcription factors is discussed; detailed maps of the genetic interactions that pattern the embryonic midgut and the larval wing imaginal disc are used to illustrate the multiplicity of potential protein-protein interactions. These interactions potentially provide direct mechanisms for communication between transcription factors as well as for generating the requisite functional specificity.

Animals↗
PubMed2002

[The "image" of the regulatory gene in experiments with Drosophila].

The mutants referred to as facultative dominant lethals were selected in the progeny of gamma-irradiated Drosophila males. The mutant males were viable and fertile, though their crosses with females of the yellow line yielded no daughters. The mutations obtained differed from the common mutations by (1) extremely varying penetrance of F1 hybrids from crosses with various lines; (2) the uncertain relationships between the mutant and normal alleles; (3) the different expression in somatic and germ cells; (4) the dependence of the expression on the sex of the parent carrying the donor mutations; (5) the mass morphosis formation and (6) the frequent reversal to the norm. These mutations are assigned to the regulatory group and their specific expression (see above) can be helpful in identifying regulatory gene mutations. We assume that the specific expression of the mutations studied is related to specific properties of the regulatory genes. These properties are as follows: (1) only one out of two homologous regulatory genes located on one homolog is in an active state, (2) in the haploid chromosome set the regulatory gene is represented by several alleles (cys-alleles); (3) only one allele ensures the regulatory gene activity.

Alleles↗
PubMed2002

Alternative epigenetic states understood in terms of specific regulatory structures.

Generally speaking, epigenetic states or epigenetic regulation refer to situations in which several states of gene expression may coexist in similar environmental conditions, despite the absence of significant changes in the genomic sequence. In one way or another, the mechanisms behind these phenomena involve vicious circles, so that each epigenetic state tends to sustain itself, even after the disappearance of the inductive signal involved in the selection of that particular state. These vicious circles constitute positive feedback circuits and are found at the core of many developmental regulatory systems. In this paper, we present a qualitative model for the regulatory network formed by maternal and gap gene cross-regulations. This network controls the initial anterior-posterior patterning during early Drosophila embryogenesis and encompasses several intertwined feedback circuits. On the basis of our model analysis, we derive interesting insights about how specific expression states of the gap genes are selected along the anterior-posterior axis, in particular in relation with the activity of one positive feedback circuit, namely that formed by giant and Krüppel cross-inhibitions. In addition, we are able to qualitatively simulate the patterns of gene expression in the wild-type, as well as to predict the phenotypes of various loss-of-function mutations at the maternal and gap genes, or cis-regulatory mutations at the gap genes, as well as the effects of ectopic expression of these genes.

Animals↗
PubMed2003

[Inactivation of reporter genes by cloned heterochromatic repeats of Drosophila melanogaster is accompanied by chromatin compaction].

Cloned Stellate heterochromatic repeats caused unstable mosaic inactivation (position effect variegation; PEV) of the reporter gene mini-white. A number of known protein modifiers of the classical position effect induced by large heterochromatin blocks do not affect the expression of mini-white. This raises the question as to the specificity of chromatin compaction around the reporter gene. The inactivation of the mini-white gene has been found to be accompanied by a decrease in its methylation catalyzed by Escherichia coli dam-methyltransferase expressed in the genome of Drosophila. However, no changes in the nucleosome organization of mini-white have been found.

Animals↗
PubMed1992

Dorsoventral development of the Drosophila embryo is controlled by a cascade of transcriptional regulators.

Maternal genes involved in dorsoventral (D/V) patterning of the Drosophila embryo interact to establish a stable nuclear concentration gradient of the Dorsal protein which acts as the morphogen along this axis. This protein belongs to the rel proto-oncogene and NF-KB transcriptional factor family and acts by controlling zygotic gene expression. In the ventral part of the embryo, dorsal specifically activates transcription of the gene twist and ventrally and laterally dorsal represses the expression of zerknüllt, a gene involved in the formation of dorsal derivatives. The extent of dorsal action is closely related to the affinity and the number of dorsal response elements present in these zygotic gene promoters. twist is one of the first zygotic genes necessary for mesoderm formation. It codes for a 'b-HLH' DNA-binding protein which can dimerize and bind to DNA in vitro and to polytene chromosomes in vivo. In addition, in cultured cells twist has been shown to be a transcriptional activator. Thus, the first events of embryonic development along the D/V axis are controlled at the transcriptional level.

Animals↗
PubMed2005

[Selection on viability of individuals heterozygous for the temperature-sensitive lethal mutation l(2)M167(DTS) in experimental populations of Drosophila melanogaster].

In experiments on introduction of mutation l(2)M167(DTS) in Drosophila melanogaster populations, larval and pupal viability and developmental rate are limiting factors determining the intensity of selection on the l(2)M167(DTS) mutation. Notwithstanding the rapid elimination of the mutation from the population, positive selection for viability was shown, which increased fitness of the mutation carriers in generations. The fitness component viability was estimated in individuals l(2)M167(DTS)/+; relative to that of wild-type individuals, it varied from 0.1 to 1. Factors affecting this trait in overcrowded populations were found.

Animals↗
PubMed2005

[Determination of fitness components of flies bearing the recessive lethal l(2)M167(DTS) mutation with dominant heat sensitivity in artificial Drosophila melanogaster populations].

Elimination of the heat-sensitive l(2)M167(DTS) mutation from artificial Drosophila melanogaster populations at constant temperature 25 degrees C and various frequencies of the mutation in the parental generation was studied. Components of fitness of the l(2)M167(DTS) mutation were estimated in the artificial populations by means of the recurrent model of the dependence of the frequency of this mutation in a given generation on its frequency in the previous generation. The model was solved by a numerical method with limitations on the values of some fitness components obtained in test experiments. According to the limitations and frequencies of the l(2)M167(DTS) mutation, the leading role and limits of the variation in egg-to-adult viability and female fertility were determined. The previously suggested effect of the positive selection for viability of individuals heterozygous for l(2)M167(DTS) was confirmed.

Animals↗
PubMed2005

[Variation of 3'-terminal fragment of 16S rRNA gene in closely related species of Drosophila virilis group].

Primary sequence of 3-terminal fragment of the mitochondrial 16S rRNA gene has been determined in 12 Drosophila species of the virilis group. The functionally important elements in secondary structure of the RNA product were defined. The region corresponding to the peptidyltransferase center has been localized. Variation of the 3'-terminal region of 16S rRNA gene has been described in 12 species of the virilis group. Phylogeny of the Drosophila virilis species group is discussed.

Animals↗