scholarly journals A Drosophila rotund transcript expressed during spermatogenesis and imaginal disc morphogenesis encodes a protein which is similar to human Rac GTPase-activating (racGAP) proteins.

1992 ◽  
Vol 12 (11) ◽  
pp. 5111-5122 ◽  
Author(s):  
M Agnel ◽  
L Röder ◽  
C Vola ◽  
R Griffin-Shea
Keyword(s):  
Cell Death ◽  
Drosophila Melanogaster ◽  
Sequence Analysis ◽  
Imaginal Disc ◽  
Germ Line ◽  
Imaginal Discs ◽  
Mutant Phenotype ◽  
Physical Characterization ◽  
Rac Gtpase

The rotund (rn) locus of Drosophila melanogaster at cytogenetic position 84D3,4 has been isolated and cloned on the basis of the mutant phenotype: an absence of structures in the subdistal regions of the appendages. The shortened appendages are the consequence of a localized cell death in the imaginal discs, precursors of the adult appendages. Physical characterization of the rn locus has demonstrated that it is relatively large, occupying a minimum of 50 kb. There are two major transcripts of 1.7 kb (m1.7) and 5.3 kb (m5.3). We present here the sequence analysis of m1.7 and its putative product, rnprot1.7, and show that rnprot1.7 is similar to the product of the human n-chimaerin gene, which is expressed in brain and testes. Recently, the GAP activity of n-chimaerin was demonstrated and shown to be specific for the Rac subfamily of the Ras oncoproteins. The Rac proteins have been implicated in the regulation of secretory processes. In addition to being expressed in the imaginal discs, the m1.7 racGAP transcript was detected in developmentally specific germ line cells of the testes, the primary spermatocytes.

A Drosophila rotund transcript expressed during spermatogenesis and imaginal disc morphogenesis encodes a protein which is similar to human Rac GTPase-activating (racGAP) proteins

1992 ◽  
Vol 12 (11) ◽  
pp. 5111-5122
Author(s):  
M Agnel ◽  
L Röder ◽  
C Vola ◽  
R Griffin-Shea
Keyword(s):  
Cell Death ◽  
Drosophila Melanogaster ◽  
Sequence Analysis ◽  
Imaginal Disc ◽  
Germ Line ◽  
Imaginal Discs ◽  
Mutant Phenotype ◽  
Physical Characterization ◽  
Rac Gtpase

The rotund (rn) locus of Drosophila melanogaster at cytogenetic position 84D3,4 has been isolated and cloned on the basis of the mutant phenotype: an absence of structures in the subdistal regions of the appendages. The shortened appendages are the consequence of a localized cell death in the imaginal discs, precursors of the adult appendages. Physical characterization of the rn locus has demonstrated that it is relatively large, occupying a minimum of 50 kb. There are two major transcripts of 1.7 kb (m1.7) and 5.3 kb (m5.3). We present here the sequence analysis of m1.7 and its putative product, rnprot1.7, and show that rnprot1.7 is similar to the product of the human n-chimaerin gene, which is expressed in brain and testes. Recently, the GAP activity of n-chimaerin was demonstrated and shown to be specific for the Rac subfamily of the Ras oncoproteins. The Rac proteins have been implicated in the regulation of secretory processes. In addition to being expressed in the imaginal discs, the m1.7 racGAP transcript was detected in developmentally specific germ line cells of the testes, the primary spermatocytes.

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.

scholarly journals Isolation and characterization of dominant female sterile mutations of Drosophila melanogaster. I. Mutations on the third chromosome.

Genetics ◽  
1989 ◽  
Vol 122 (1) ◽  
pp. 111-127 ◽  
Author(s):  
M Erdélyi ◽  
J Szabad
Keyword(s):  
Drosophila Melanogaster ◽  
Germ Line ◽  
Female Sterility ◽  
Male Germ Line ◽  
The Third ◽  
Egg Retention ◽  
Isolation And Characterization ◽  
Dominant Female ◽  
New Alleles

Abstract Fifty-one dominant female sterile (Fs) mutations linked to the third chromosome of Drosophila melanogaster are described. EMS induced Fs mutations arise with the frequency of one Fs per about 2500 recessive lethals. Complementation analysis of the revertants showed that these Fs mutations represent 27-34 loci, about 60% of the third chromosome units mutable to dominant female sterility by EMS. The Fs mutations were mapped on the basis of mitotic recombination induced in the female (in 16 cases also in the male) germ-line. Behavior of the revertants and the Fs+ germ-line clones demonstrate the gain-of-function nature of the Fs alleles. With two exceptions, the Fs(3) mutations are germ-line dependent. Novel phenotypes appeared in most of the Fs mutations. With eight exceptions, the Fs(3) mutations are fully penetrant, in some cases with variable expressivity. One of the Fs(3) mutations is a non-ovary-dependent egg retention mutation, two others alter egg shape, and 27 bring about arrest in development at about the time of fertilization. In 21 of the Fs(3) mutations embryos develop to the larval stage of differentiation; this group includes 5 new alleles of Toll and 4 of easter.

Gene expression during imaginal disc regeneration detected using enhancer-sensitive P-elements

Development ◽  
1993 ◽  
Vol 117 (4) ◽  
pp. 1287-1297 ◽  
Author(s):  
W.J. Brook ◽  
L.M. Ostafichuk ◽  
J. Piorecky ◽  
M.D. Wilkinson ◽  
D.J. Hodgetts ◽  
...  
Keyword(s):  
Cell Death ◽  
Imaginal Disc ◽  
Expression Patterns ◽  
Imaginal Discs ◽  
P Element ◽  
Temperature Sensitive ◽  
Lethal Mutant ◽  
Disc Regeneration ◽  
Lac Z ◽  
Regeneration Blastema

When imaginal disc fragments from Drosophila are cultured in adult female hosts, they either duplicate the part of the pattern specified by the fate map, or regenerate to replace the missing part. The new tissue is added by proliferation of a small number of cells from the cut edge, brought together when the wound heals to form a regeneration blastema. Specification of the new pattern has been explained by assuming interactions among cells of different positional value in the regeneration blastema. In order to identify genes which might mediate these events, we screened over eight hundred independently isolated autosomal insertions of an enhancer-sensitive P-element, for altered lac-z expression in regenerating discs following cell death induced by a temperature-sensitive cell-lethal mutation. Two further screens divided the positive lines into four groups based on appropriate timing of the lac-z response in the cell-lethal mutant background and the expected response to an alternate source of cell death. Expression in wing disc fragments cultured in vivo was most frequent in the target class defined by the screens. In this direct test, lac-z expression was found in 23 lines and in most cases was spatially and temporally correlated with the formation of the regeneration blastema. Our results suggest a very substantial transcriptional response during the early stages of imaginal disc regeneration. lac-z expression in control imaginal discs, embryos and adult ovaries of the positive lines was also assayed. The selected insertions included: a small class expressed only in discs undergoing regeneration and apparently not at any other stage, possibly representing genes active exclusively in regeneration; a larger class expressed in the embryo or during oogenesis, but not normally in imaginal discs, as expected for functions recruited from earlier stages of the developmental program; and finally a class with spatially patterned expression in normal discs. This class included several insertions with expression associated with compartment boundaries, including one at the decapentaplegic (dpp), and one at the crumbs (crb) locus, a growth factor homologue, and an EGF-repeat gene respectively. Some of the expression patterns observed in cultured disc fragments provide evidence for cell communication in the regeneration blastema.

scholarly journals THE ABSENCE OF SOMATIC EFFECTS OF P-M HYBRID DYSGENESIS IN DROSOPHILA MELANOGASTER

Genetics ◽  
1986 ◽  
Vol 113 (4) ◽  
pp. 897-918
Author(s):  
M Catharine McElwain
Keyword(s):  
Drosophila Melanogaster ◽  
Size Distribution ◽  
De Novo ◽  
Germ Line ◽  
Adaptive Significance ◽  
Hybrid Dysgenesis ◽  
De Novo Mutation ◽  
Anatomical Distribution ◽  
Parallel Processes

ABSTRACT The wings and abdomens of dysgenic and nondysgenic control flies were scored for the presence of clones of cells mutant for first and third chromosome markers. These exceptional clones can arise from mitotic recombination, de novo mutation or deletion, and P-M hybrid dysgenesis has been shown to increase the frequency of parallel processes occurring in germ-line cells. Particular attention was given to careful genetic and molecular characterization of all stocks and to providing adequate and appropriate controls so that even very small increases in somatic clone frequency due to P-M hybrid dysgenesis would be detected. No difference was found in the frequency, size distribution or anatomical distribution of mutant somatic clones correlated to hybrid dysgenesis, confirming previous indications. The potential adaptive significance of a germ-line restriction of P-M hybrid dysgenesis is discussed.

scholarly journals Molecular Cloning and Tissue-Specific Expression of the mutator2 Gene (mu2) in Drosophila melanogaster

Genetics ◽  
1999 ◽  
Vol 152 (3) ◽  
pp. 1025-1035
Author(s):  
Armin Kasravi ◽  
Marika F Walter ◽  
Stephanie Brand ◽  
James M Mason ◽  
Harald Biessmann
Keyword(s):  
Drosophila Melanogaster ◽  
Molecular Cloning ◽  
Germ Line ◽  
Molecular Data ◽  
Mutant Phenotype ◽  
Oocyte Nucleus ◽  
Proliferating Cells ◽  
Specific Expression ◽  
Nuclear Localization Signals ◽  
Helix Loop Helix

Abstract We present here the molecular cloning and characterization of the mutator2 (mu2) gene of Drosophila melanogaster together with further genetic analyses of its mutant phenotype. mu2 functions in oogenesis during meiotic recombination, during repair of radiation damage in mature oocytes, and in proliferating somatic cells, where mu2 mutations cause an increase in somatic recombination. Our data show that mu2 represents a novel component in the processing of double strand breaks (DSBs) in female meiosis. mu2 does not code for a DNA repair enzyme because mu2 mutants are not hypersensitive to DSB-inducing agents. We have mapped and cloned the mu2 gene and rescued the mu2 phenotype by germ-line transformation with genomic DNA fragments containing the mu2 gene. Sequencing its cDNA demonstrates that mu2 encodes a novel 139-kD protein, which is highly basic in the carboxy half and carries three nuclear localization signals and a helix-loop-helix domain. Consistent with the sex-specific mutant phenotype, the gene is expressed in ovaries but not in testes. During oogenesis its RNA is rapidly transported from the nurse cells into the oocyte where it accumulates specifically at the anterior margin. Expression is also prominent in diploid proliferating cells of larval somatic tissues. Our genetic and molecular data are consistent with the model that mu2 encodes a structural component of the oocyte nucleus. The MU2 protein may be involved in controlling chromatin structure and thus may influence the processing of DNA DSBs.

scholarly journals The relaxin receptor Lgr3 mediates growth coordination and developmental delay during Drosophila melanogaster imaginal disc regeneration

2015 ◽  
Author(s):  
Jacob S. Jaszczak ◽  
Jacob B. Wolpe ◽  
Rajan Bhandari ◽  
Rebecca G. Jaszczak ◽  
Adrian Halme
Keyword(s):  
Drosophila Melanogaster ◽  
Developmental Delay ◽  
Imaginal Disc ◽  
Imaginal Discs ◽  
Prothoracic Gland ◽  
Disc Regeneration ◽  
Relaxin Family ◽  
Dependent Growth ◽  
Oxide Synthase ◽  
Relaxin Receptor

Damage to Drosophila melanogaster imaginal discs activates a regeneration checkpoint that 1) extends larval development and 2) coordinates the regeneration of the damaged disc with the growth of undamaged discs. These two systemic responses to damage are both mediated by Dilp8, a member of the insulin/IGF/relaxin family of peptide hormones, which is released by regenerating imaginal discs. Growth coordination between regenerating and undamaged imaginal discs is dependent on Dilp8 activation of NOS in the prothoracic gland (PG), which slows the growth of undamaged discs by limiting ecdysone synthesis. Here we demonstrate that the Drosophila relaxin receptor homologue Lgr3, a leucine-rich repeat-containing G-protein coupled receptor, is required for Dilp8-dependent growth coordination and developmental delay during the regeneration checkpoint. Lgr3 regulates these responses to damage via distinct mechanisms in different tissues. Using tissue-specific RNAi disruption of Lgr3 expression, we show that Lgr3 functions in the PG upstream of nitric oxide synthase (NOS), and is necessary for NOS activation and growth coordination during the regeneration checkpoint. When Lgr3 is depleted from neurons, imaginal disc damage no longer produces either developmental delay or growth inhibition. To reconcile these discrete tissue requirements for Lgr3 during regenerative growth coordination, we demonstrate that Lgr3 activity in the both the CNS and PG is necessary for NOS activation in the PG following damage. Together, these results identify new roles for a relaxin receptor in mediating damage signaling to regulate growth and developmental timing.

scholarly journals Analysis in Drosophila melanogaster of the Interaction Between Sex Combs Reduced and Extradenticle Activity in the Determination of Tarsus and Arista Identity

Genetics ◽  
1998 ◽  
Vol 150 (1) ◽  
pp. 189-198
Author(s):  
Anthony Percival-Smith ◽  
Danielle J Hayden
Keyword(s):  
Drosophila Melanogaster ◽  
Imaginal Disc ◽  
Imaginal Discs ◽  
Nuclear Accumulation ◽  
Sex Combs Reduced ◽  
Sex Combs ◽  
Disc Cells

Abstract Sex Combs Reduced (SCR) activity is proposed to be required cell nonautonomously for determination of tarsus identity, and Extradenticle (EXD) activity is required cell autonomously for determination of arista identity. Using the ability of Proboscipedia to inhibit the SCR activity required for determination of tarsus identity, we found that loss-of-EXD activity is epistatic to loss-of-SCR activity in tarsus vs. arista determination. This suggests that in the sequence leading to arista determination SCR activity is OFF while EXD activity is ON, and in the sequence leading to tarsus determination SCR activity is ON, which turns EXD activity OFF. Immunolocalization of EXD in early third-instar larval imaginal discs reveals that EXD is localized in the nuclei of antennal imaginal disc cells and localized in the cytoplasm of distal imaginal leg disc cells. We propose that EXD localized to the nucleus suppresses tarsus determination and activates arista determination. We further propose that in the mesodermal adepithelial cells of the leg imaginal discs, SCR is required for the synthesis of a tarsus-inducer that when secreted acts on the ectoderm cells inhibiting nuclear accumulation of EXD, such that tarsus determination is no longer suppressed and arista determination is no longer activated.

Cell lineage of larval and imaginal thoracic anlagen cells of Drosophila melanogaster, as revealed by single-cell transplantations

Development ◽  
1993 ◽  
Vol 118 (4) ◽  
pp. 1107-1121 ◽  
Author(s):  
M. Meise ◽  
W. Janning
Keyword(s):  
Nervous System ◽  
Drosophila Melanogaster ◽  
Imaginal Disc ◽  
Single Cells ◽  
Cell Lineage ◽  
Imaginal Discs ◽  
Lacz Gene ◽  
Gastrula Stage ◽  
Clone Size ◽  
Early Gastrula

We have analyzed the cell lineage of larval and imaginal cells in the thoracic ectoderm of the early embryo of Drosophila melanogaster, by homotopic transplantation of single cells in the region of 50–60% egg length. Single cells were isolated prior to transplantation in an in vitro solution. The donors were ‘enhancer-trap’ lines in which the nuclei of all larval and imaginal cells exhibit a uniformly intense expression of the lacZ gene of E. coli. The transplantations were carried out from the blastoderm to the early gastrula stage, as a rule immediately after the onset of gastrulation (stage 6). It was found that at this time the cells of the thoracic ectoderm are not yet committed to form larval or imaginal structures, as indicated by the presence of clones overlapping all structures formed by the thoracic ectoderm, i.e. the nervous system, the larval epidermis, the tracheae and the imaginal discs. The average size of pure epidermal clones was five cells. In clones overlapping either other larval tissues or imaginal discs, the average number of epidermal cells was between three and four. The mean relative clone size was 1/5 of the size of the total structure for leg imaginal discs and 1/7 for the wing imaginal disc. We therefore infer that the precursors for the leg discs and wing disc on one side together number 22 cells in the blastoderm or early gastrula stage. These cells eventually give rise not only to precursors of the imaginal discs but usually also to larval epidermal and nervous-system cells, because most of the imaginal disc clones (80%) overlap larval tissue. The transplantations were not precisely homotopic; the fact that up to 10 cells were removed from the donor essentially rules out exact homotopy between donor and host sites, because a segment anlage is only about three cells wide. Nevertheless, the clones developed completely normal tissue together with the recipient cells. Although the clones have the capacity to extend over different ectodermal tissues and can include both imaginal discs in a given segment, no clones were found that clearly crossed larval or imaginal segment boundaries. We propose a model in which the segregation of the cells that are to differentiate into the imaginal tissues does not occur until the second postblastodermal mitosis

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