Germ-line expression of the I factor, a functional LINE from the fruit fly Drosophila melanogaster, is positively regulated by reactivity, a peculiar cellular state

1993 ◽  
Vol 240 (2) ◽  
pp. 277-285 ◽  
Author(s):  
Philippe Lachaume ◽  
Hubert Pinon
Keyword(s):  
Drosophila Melanogaster ◽  
Germ Line ◽  
Fruit Fly ◽  
I Factor

scholarly journals IR hybrid dysgenesis increases the frequency of recombination in Drosophila melanogaster

1995 ◽  
Vol 65 (3) ◽  
pp. 167-174 ◽  
Author(s):  
Marie-Christine Chaboissier ◽  
Françoise Lemeunier ◽  
Alain Bucheton
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Element ◽  
High Frequency ◽  
Germ Line ◽  
Hybrid Dysgenesis ◽  
High Rate ◽  
I Factor

SummaryThe I factor is a LINE-like transposable element responsible for the I-R system of hybrid dysgenesis in Drosophila melanogaster. Inducer strains of this species contain several I factors whereas reactive strains do not. I factors are stable in inducer strains, but transpose at high frequency in the germ-line of females, known as SF females, produced by crossing reactive females and inducer males. Various abnormalities occur in SF females, most of which result from this high rate of transposition. We report here that recombination is increased in the germ-line of these females. This is a new characteristic of the I-R system of hybrid dysgenesis that might also be associated with transposition of the I factor.

scholarly journals New Insights on Homology-Dependent Silencing of I Factor Activity by Transgenes Containing ORF1 in Drosophila melanogaster

Genetics ◽  
2000 ◽  
Vol 156 (3) ◽  
pp. 1147-1155 ◽  
Author(s):  
Sophie Malinsky ◽  
Alain Bucheton ◽  
Isabelle Busseau
Keyword(s):  
Drosophila Melanogaster ◽  
Germ Line ◽  
Ltr Retrotransposons ◽  
Factor Activity ◽  
Hsp70 Promoter ◽  
Transgene Copy Number ◽  
High Frequencies ◽  
I Factor ◽  
Very High Frequencies ◽  
Very High

Abstract I factors in Drosophila melanogaster are non-LTR retrotransposons that transpose at very high frequencies in the germ line of females resulting from crosses between reactive females (devoid of active I factors) and inducer males (containing active I factors). Constructs containing I factor ORF1 under the control of the hsp70 promoter repress I factor activity. This repressor effect is maternally transmitted and increases with the transgene copy number. It is irrespective of either frame integrity or transcriptional orientation of ORF1, suggesting the involvement of a homology-dependent trans-silencing mechanism. A promoterless transgene displays no repression. The effect of constructs in which ORF1 is controlled by the hsp70 promoter does not depend upon heat-shock treatments. No effect of ORF1 is detected when it is controlled by the I factor promoter. We discuss the relevance of the described regulation to the repression of I factors in I strains.

Evidence for a Multistep Control in Transposition of I Factor in Drosophila melanogaster

Genetics ◽  
1998 ◽  
Vol 148 (4) ◽  
pp. 1875-1884
Author(s):  
Christophe de La Roche Saint André ◽  
Jean-Claude Bregliano
Keyword(s):  
Drosophila Melanogaster ◽  
High Frequency ◽  
Genetic Background ◽  
Germ Line ◽  
Positive Control ◽  
Negative Control ◽  
Rt Pcr ◽  
I Factor ◽  
Full Length Transcript ◽  
Different Levels

Abstract Drosophila melanogaster strains belong to one of two interactive categories, inducer (I) or reactive (R), with respect to the I-R system of hybrid dysgenesis. The dysgenic interaction results from the presence of several transposition-competent copies of a LINE-like element, the I factor, only in the genome of I strains. When a cross is performed between I males and R females, I factor transposes at high frequency in the germ line of F1 daughters, known as SF females. This transposition burst results in the sterility of SF females. I factor transposes by reverse transcription of a full-length transcript. Specific RT-PCR experiments were done to compare the amount of I factor transcript in samples corresponding to various transposition frequencies. The sensitivity of the method allowed the ready detection of the I factor RNA in every tissue and genetic background examined. Comparison of amplification signals suggests that I factor activity in ovaries is regulated at different levels. First, the amount of I factor RNA subjected to negative and positive regulation. Whereas the negative control, which limits transposition in nonpermissive contexts, may be exerted by an I factor encoded repressor function, the positive control is linked to reactivity level, a cellular state maternally inherited from R mothers. Additionally, negative regulation is also exerted downstream of I factor RNA. This differs notably from previous conclusions in which transcription was envisaged as the main level of regulation of the I factor transposition.

scholarly journals Evidence for an inducible repair-recombination system in the female germ line of Drosophila melanogaster. I. Induction by inhibitors of nucleotide synthesis and by gamma rays.

Genetics ◽  
1995 ◽  
Vol 141 (2) ◽  
pp. 571-578 ◽  
Author(s):  
J C Bregliano ◽  
A Laurençon ◽  
F Degroote
Keyword(s):  
Drosophila Melanogaster ◽  
Gamma Rays ◽  
Line Element ◽  
Germ Line ◽  
Nucleotide Synthesis ◽  
Transposition Frequency ◽  
Recombination System ◽  
I Factor ◽  
Female Germ Line ◽  
Inducible Repair

Abstract In the I-R system of hybrid dysgenesis in Drosophila melanogaster, the transposition frequency of I factor, a LINE element-like retrotransposon, is regulated by the reactivity level of the R mother. This reactivity is a cellular state maternally inherited but chromosomally determined, which has been shown to undergo heritable, cumulative and reversible changes with aging and some environmental conditions. We propose the hypothesis that this reactivity level is one manifestation of an inducible repair-recombination system whose biological role might be analogous to the SOS response in bacteria. In this paper, we show that inhibitors of DNA synthesis and gamma rays enhance the reactivity level in a very similar way. This enhancement is heritable, cumulative and reversible.

Spatial and temporal expression of the I factor during oogenesis in Drosophila melanogaster

Development ◽  
1992 ◽  
Vol 115 (3) ◽  
pp. 729-735 ◽  
Author(s):  
P. Lachaume ◽  
K. Bouhidel ◽  
M. Mesure ◽  
H. Pinon
Keyword(s):  
Drosophila Melanogaster ◽  
Nuclear Localization ◽  
Germ Line ◽  
Transcriptional Level ◽  
Regulatory Sequences ◽  
Lacz Gene ◽  
Position Effects ◽  
Nuclear Localization Signals ◽  
I Factor

The I factor is a functional non-viral retrotransposon, or LINE, from Drosophila melanogaster. Its mobility is associated with the I-R hybrid dysgenesis. In order to study the expression pattern of this LINE in vivo, a translational fusion between the first ORF of the I factor and the lacZ gene of Escherichia coli has been carried out and introduced in the genome of reactive (R) flies. Homozygous transgenic Drosophila lines have been established and analysed. ORF1 expression is limited to germ-line cells (nurse cells and oocyte) between stage 2 and 10 of oogenesis. No somatic expression is found. Position effects may limit the level of expression of a given transgene but do not modify its basic pattern of expression during the development of the fly. This reproducible control demonstrates both that I factor is driven by its own promoter, probably the internal one suggested by Mizrokhi et al. (Mizrokhi, L.J., Georgevia, S.G. and Ilying, Y.V. (1988). Cell 54, 685–691), and that tissue-specific regulatory sequences are present in the 5′ untranslated part of the I factor. The nuclear localization of the fusion protein reveals the presence of nuclear localization signals (NLS) in the ORF1-encoded protein correlating with the possible structural and/or regulatory role of this protein. This expression is restricted to dysgenic and reactive females, and is similar in the two conditions. All the results obtained in this work suggest that I factor transposition occurs as a meiotic event, between stage 2 and 10 of the oogenesis and is regulated at the transcriptional level. It also appears that our transgene is an efficient marker to follow I factor expression.

scholarly journals piRNA pathway is not required for antiviral defense in Drosophila melanogaster

2016 ◽  
Vol 113 (29) ◽  
pp. E4218-E4227 ◽  
Author(s):  
Marine Petit ◽  
Vanesa Mongelli ◽  
Lionel Frangeul ◽  
Hervé Blanc ◽  
Francis Jiggins ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Germ Line ◽  
Fruit Fly ◽  
Antiviral Response ◽  
Antiviral Defense ◽  
Wild Type ◽  
Cellular Processes ◽  
Pirna Pathway ◽  
Interfering Rna ◽  
Sirna Pathway

Since its discovery, RNA interference has been identified as involved in many different cellular processes, and as a natural antiviral response in plants, nematodes, and insects. In insects, the small interfering RNA (siRNA) pathway is the major antiviral response. In recent years, the Piwi-interacting RNA (piRNA) pathway also has been implicated in antiviral defense in mosquitoes infected with arboviruses. Using Drosophila melanogaster and an array of viruses that infect the fruit fly acutely or persistently or are vertically transmitted through the germ line, we investigated in detail the extent to which the piRNA pathway contributes to antiviral defense in adult flies. Following virus infection, the survival and viral titers of Piwi, Aubergine, Argonaute-3, and Zucchini mutant flies were similar to those of wild type flies. Using next-generation sequencing of small RNAs from wild type and siRNA mutant flies, we showed that no viral-derived piRNAs were produced in fruit flies during different types of viral infection. Our study provides the first evidence, to our knowledge, that the piRNA pathway does not play a major role in antiviral defense in adult Drosophila and demonstrates that viral-derived piRNA production depends on the biology of the host–virus combination rather than being part of a general antiviral process in insects.

scholarly journals Evidence for an inducible repair-recombination system in the female germ line of Drosophila melanogaster. II. Differential sensitivity to gamma rays.

Genetics ◽  
1995 ◽  
Vol 141 (2) ◽  
pp. 579-585 ◽  
Author(s):  
A Laurençon ◽  
J C Bregliano
Keyword(s):  
Drosophila Melanogaster ◽  
Gamma Rays ◽  
Germ Line ◽  
Differential Sensitivity ◽  
Repair System ◽  
Recombination System ◽  
I Factor ◽  
Female Germ Line ◽  
Dominant Lethals ◽  
Inducible Repair

Abstract In a previous paper, we reported that the reactivity level, which regulates the frequency of transposition of I factor, a LINE element-like retrotransposon, is enhanced by the same agents that induce the SOS response in Escherichia coli. In this report, we describe experimental evidence that, for identical genotypes, the reactivity levels correlate with the sensitivity of oogenesis to gamma rays, measured by the number of eggs laid and by frequency of dominant lethals. This strongly supports the hypothesis that the reactivity level is one manifestation of an inducible DNA repair system taking place in the female germ line of Drosophila melanogaster. The implications of this finding for the understanding of the regulation of I factor are discussed and some other possible biological roles of this system are outlined.

scholarly journals Hox dosage contributes to flight appendage morphology in Drosophila

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rachel Paul ◽  
Guillaume Giraud ◽  
Katrin Domsch ◽  
Marilyne Duffraisse ◽  
Frédéric Marmigère ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Differential Expression ◽  
Hox Genes ◽  
Expression Profiles ◽  
Fruit Fly ◽  
Insect Species ◽  
Wing Morphology ◽  
Hox Proteins ◽  
Spatial Expression ◽  
Flying Insects

AbstractFlying insects have invaded all the aerial space on Earth and this astonishing radiation could not have been possible without a remarkable morphological diversification of their flight appendages. Here, we show that characteristic spatial expression profiles and levels of the Hox genes Antennapedia (Antp) and Ultrabithorax (Ubx) underlie the formation of two different flight organs in the fruit fly Drosophila melanogaster. We further demonstrate that flight appendage morphology is dependent on specific Hox doses. Interestingly, we find that wing morphology from evolutionary distant four-winged insect species is also associated with a differential expression of Antp and Ubx. We propose that variation in the spatial expression profile and dosage of Hox proteins is a major determinant of flight appendage diversification in Drosophila and possibly in other insect species during evolution.

scholarly journals Expression of a gene duplication encoding conserved sperm tail proteins is translationally regulated in Drosophila melanogaster.

1993 ◽  
Vol 13 (3) ◽  
pp. 1708-1718 ◽  
Author(s):  
M Schäfer ◽  
D Börsch ◽  
A Hülster ◽  
U Schäfer
Keyword(s):  
Drosophila Melanogaster ◽  
Gene Family ◽  
Translational Control ◽  
Germ Line ◽  
Gene Families ◽  
Homologous Gene ◽  
Male Sterile ◽  
Sperm Tail ◽  
Repetitive Motif ◽  
Carboxy Terminal

We have analyzed a locus of Drosophila melanogaster located at 98C on chromosome 3, which contains two tandemly arranged genes, named Mst98Ca and Mst98Cb. They are two additional members of the Mst(3)CGP gene family by three criteria. (i) Both genes are exclusively transcribed in the male germ line. (ii) Both transcripts encode a protein with a high proportion of the repetitive motif Cys-Gly-Pro. (iii) Their expression is translationally controlled; while transcripts can be detected in diploid stages of spermatogenesis, association with polysomes can be shown only in haploid stages of sperm development. The genes differ markedly from the other members of the gene family in structure; they do not contain introns, they are of much larger size, and they have the Cys-Gly-Pro motifs clustered at the carboxy-terminal end of the encoded proteins. An antibody generated against the Mst98Ca protein recognizes both Mst98C proteins in D. melanogaster. In a male-sterile mutation in which spermiogenesis is blocked before individualization of sperm, both of these proteins are no longer synthesized. This finding provides proof of late translation for the Mst98C proteins and thereby independent proof of translational control of expression. Northern (RNA) and Western immunoblot analyses indicate the presence of homologous gene families in many other Drosophila species. The Mst98C proteins share sequence homology with proteins of the outer dense fibers in mammalian spermatozoa and can be localized to the sperm tail by immunofluorescence with an anti-Mst98Ca antibody.

scholarly journals Genetic and Molecular Characterization of sting, a Gene Involved in Crystal Formation and Meiotic Drive in the Male Germ Line of Drosophila melanogaster

Genetics ◽  
1999 ◽  
Vol 151 (2) ◽  
pp. 749-760 ◽  
Author(s):  
Armin Schmidt ◽  
Gioacchino Palumbo ◽  
Maria P Bozzetti ◽  
Patrizia Tritto ◽  
Sergio Pimpinelli ◽  
...  
Keyword(s):  
Amino Acids ◽  
Drosophila Melanogaster ◽  
Null Allele ◽  
Germ Line ◽  
Meiotic Drive ◽  
P Element ◽  
Crystal Formation ◽  
Male Sterile ◽  
Male Sterile Mutation

Abstract The sting mutation, caused by a P element inserted into polytene region 32D, was isolated by a screen for male sterile insertions in Drosophila melanogaster. This sterility is correlated with the presence of crystals in spermatocytes and spermatids that are structurally indistinguishable from those produced in males carrying a deficiency of the Y-linked crystal (cry) locus. In addition, their morphology is needle-like in Ste+ flies and star-shaped in Ste flies, once again as observed in cry– males. The sti mutation leads to meiotic drive of the sex chromosomes, and the strength of the phenomenon is correlated with the copy number of the repetitive Ste locus. The same correlation is also true for the penetrance of the male sterile mutation. A presumptive sti null allele results in male sterility and lethal maternal effect. The gene was cloned and shown to code for a putative protein that is 866 amino acids long. A C-terminal domain of 82 amino acids is identified that is well conserved in proteins from different organisms. The gene is expressed only in the germline of both sexes. The interaction of sting with the Ste locus can also be demonstrated at the molecular level. While an unprocessed 8-kb Ste primary transcript is expressed in wild-type males, in X/Y homozygous sti males, as in X/Y cry– males, a 0.7-kb mRNA is produced.

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