Generation and early differentiation of glial cells in the first optic ganglion of Drosophila melanogaster

Development ◽  
1992 ◽  
Vol 115 (4) ◽  
pp. 903-911 ◽  
Author(s):  
M.L. Winberg ◽  
S.E. Perez ◽  
H. Steller
Keyword(s):  
Drosophila Melanogaster ◽  
Glial Cells ◽  
Enhancer Trap ◽  
P Element ◽  
Cell Divisions ◽  
Genetic Mosaic ◽  
First Optic Ganglion ◽  
Optic Ganglion ◽  
Glial Lineage ◽  
Enhancer Trap Lines

We have examined the generation and development of glial cells in the first optic ganglion, the lamina, of Drosophila melanogaster. Previous work has shown that the growth of retinal axons into the developing optic lobes induces the terminal cell divisions that generate the lamina monopolar neurons. We investigated whether photoreceptor ingrowth also influences the development of lamina glial cells, using P element enhancer trap lines, genetic mosaics and birthdating analysis. Enhancer trap lines that mark the differentiating lamina glial cells were found to require retinal innervation for expression. In mutants with only a few photoreceptors, only the few glial cells near ingrowing axons expressed the marker. Genetic mosaic analysis indicates that the lamina neurons and glial cells are readily separable, suggesting that these are derived from distinct lineages. Additionally, BrdU pulse-chase experiments showed that the cell divisions that produce lamina glia, unlike those producing lamina neurons, are not spatially or temporally correlated with the retinal axon ingrowth. Finally, in mutants lacking photoreceptors, cell divisions in the glial lineage appeared normal. We conclude that the lamina glial cells derive from a lineage that is distinct from that of the L-neurons, that glia are generated independently of photoreceptor input, and that completion of the terminal glial differentiation program depends, directly or indirectly, on an inductive signal from photoreceptor axons.

scholarly journals hobo enhancer trapping mutagenesis in Drosophila reveals an insertion specificity different from P elements.

Genetics ◽  
1993 ◽  
Vol 135 (4) ◽  
pp. 1063-1076 ◽  
Author(s):  
D Smith ◽  
J Wohlgemuth ◽  
B R Calvi ◽  
I Franklin ◽  
W M Gelbart
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Element ◽  
Enhancer Trap ◽  
P Element ◽  
Present Evidence ◽  
P Elements ◽  
Element Insertion ◽  
Enhancer Trapping ◽  
Indispensable Tool

Abstract P element enhancer trapping has become an indispensable tool in the analysis of the Drosophila melanogaster genome. However, there is great variation in the mutability of loci by these elements such that some loci are relatively refractory to insertion. We have developed the hobo transposable element for use in enhancer trapping and we describe the results of a hobo enhancer trap screen. In addition, we present evidence that a hobo enhancer trap element has a pattern of insertion into the genome that is different from the distribution of P elements in the available database. Hence, hobo insertion may facilitate access to genes resistant to P element insertion.

Identification of fat-cell enhancer activity in Drosophila melanogaster using P-element enhancer traps

Genome ◽  
1995 ◽  
Vol 38 (3) ◽  
pp. 497-506 ◽  
Author(s):  
Deborah Keiko Hoshizaki ◽  
Rayna Lunz ◽  
Wade Johnson ◽  
Mita Ghosh
Keyword(s):  
Gene Expression ◽  
Target Genes ◽  
Cell Function ◽  
Zinc Finger Protein ◽  
Fat Body ◽  
Enhancer Trap ◽  
P Element ◽  
Specific Gene ◽  
Fat Cell ◽  
Enhancer Trap Lines

To identify genes important in fat-cell metabolism and development, we have screened Drosophila stocks carrying an engineered transposable element that can reveal the presence of nearby enhancer elements. We have identified those "enhancer-trap lines" that contain transposable P elements integrated near fat-cell specific enhancer elements. We anticipate that the genes associated with these enhancers will provide information concerning fat-cell function and serve as target genes for studying fat-cell specific gene expression. Furthermore, the identification of enhancer-trap lines active in the developing fat cell should provide an entry point into the molecular and genetic analysis of early fat-cell development. Analysis of two lines has revealed that the transcription factors svp, a steroid-hormone receptor, and Kr, a zinc-finger protein, are present in the fat body; these factors are likely to be involved in fat-cell gene expression. In two other lines, β-galactosidase was detected in a subset of adepithelial cells that may be the precursors to the adult fat cell. And finally, in a single line transgene activity is present in the progenitor cells of the embryonic fat body. The genes associated with these enhancer-trap lines may be involved in fat-cell development.Key words: adepithelial cells, precursor fat cells, enhancers, mesoderm, differentiation.

scholarly journals An Analysis Using the hobo Genetic System Reveals That Combinatorial Signaling by the Dpp and Wg Pathways Regulates dpp Expression in Leading Edge Cells of the Dorsal Ectoderm in Drosophila melanogaster

Genetics ◽  
2002 ◽  
Vol 161 (2) ◽  
pp. 685-692 ◽  
Author(s):  
S J Newfeld ◽  
N T Takaesu
Keyword(s):  
Drosophila Melanogaster ◽  
Transforming Growth Factor ◽  
Leading Edge ◽  
Genetic System ◽  
Transforming Growth Factor Β ◽  
Enhancer Trap ◽  
P Element ◽  
Developmental Systems ◽  
Mrna Accumulation ◽  
Dorsal Ectoderm

Abstract Our laboratory has contributed to the development of a genetic system based upon the hobo transposable element in Drosophila melanogaster. We recently reported that hobo, like the better-known P element, is capable of local transposition. In that study, we mobilized a hobo enhancer trap vector and generated two unique alleles of decapentaplegic (dpp), a transforming growth factor-β family member with numerous roles during development. Here we report a detailed study of one of those alleles (dppF11). To our knowledge, this is the first application of the hobo genetic system to understanding developmental processes. First, we demonstrate that lacZ expression from the dppF11 enhancer trap accurately reflects dpp mRNA accumulation in leading edge cells of the dorsal ectoderm. Then we show that combinatorial signaling by the Wingless (Wg) pathway, the Dpp pathway, and the transcriptional coactivator Nejire (CBP/p300) regulates dppF11 expression in these cells. Our analysis of dppF11 suggests a model for the integration of Wg and Dpp signals that may be applicable to other developmental systems. Our analysis also illustrates several new features of the hobo genetic system and highlights the value of hobo, as an alternative to P, in addressing developmental questions.

scholarly journals Effects of Single P-Element Insertions on Olfactory Behavior in Drosophila melanogaster

Genetics ◽  
1996 ◽  
Vol 143 (1) ◽  
pp. 293-301 ◽  
Author(s):  
Robert R H Anholt ◽  
Richard F Lyman ◽  
Trudy F C Mackay
Keyword(s):  
Drosophila Melanogaster ◽  
Avoidance Response ◽  
Insertional Mutagenesis ◽  
Enhancer Trap ◽  
P Element ◽  
Olfactory Behavior ◽  
Tissue Specific ◽  
Isogenic Strain ◽  
Tissue Specific Promoter ◽  
Olfactory Tissue

Abstract Single P-element (P[lArB]) insertional mutagenesis of an isogenic strain was used to identify autosomal loci affecting odor-guided behavior of Drosophila melanogaster. The avoidance response to benzaldehyde of 379 homozygous P[lArB] element-containing insert lines was evaluated quantitatively. Fourteen smell impaired (smi) lines were identified in which P[lArB] element insertion caused different degrees of hyposmia in one or both sexes. The smi loci map to different cytological locations and probably are novel olfactory genes. Enhancer trap analysis of the smi lines indicates that expression of at least 10 smi genes is controlled by olfactory tissue-specific promoter/enhancer elements.

Development and organization of glial cells in the peripheral nervous system of Drosophila melanogaster

Development ◽  
1993 ◽  
Vol 117 (3) ◽  
pp. 895-904 ◽  
Author(s):  
A. Giangrande ◽  
M.A. Murray ◽  
J. Palka
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Drosophila Melanogaster ◽  
Peripheral Nervous System ◽  
Glial Cells ◽  
Adult Development ◽  
Early Event ◽  
The Central Nervous System ◽  
Wing Discs ◽  
Enhancer Trap Lines

We have used enhancer trap lines as markers to recognize glial cells in the wing peripheral nervous system of Drosophila melanogaster. Their characterization has enabled us to define certain features of glial differentiation and organization. In order to ask whether glial cells originate within the disc or whether they migrate to the wing nerves from the central nervous system, we used two approaches. In cultured wing discs from glial-specific lines, peripheral glial precursors are already present within the imaginal tissue during the third larval stage. Glial cells differentiate on a wing nerve even in mutants in which that nerve does not connect to the central nervous system. To assess whether peripheral glial cells originate from ectoderm or from mesoderm, we cultured discs from which the mesodermally derived adepithelial cells had been removed. Our findings indicate that peripheral glial cells originate from ectodermally derived cells. As has already been shown for the embryonic central nervous system, gliogenesis in the periphery is an early event during adult development: glial cells, or their precursors, are already present at stages when neurons are still differentiating. Finally, our results also suggest that peripheral glial cells may not display a stereotyped arrangement.

scholarly journals A hobo Transgene That Encodes the P-Element Transposase in Drosophila melanogaster: Autoregulation and Cytotype Control of Transposase Activity

Genetics ◽  
2002 ◽  
Vol 161 (1) ◽  
pp. 195-204 ◽  
Author(s):  
Michael J Simmons ◽  
Kevin J Haley ◽  
Craig D Grimes ◽  
John D Raymond ◽  
Jarad B Niemi
Keyword(s):  
Drosophila Melanogaster ◽  
Gonadal Dysgenesis ◽  
P Element ◽  
Hsp70 Gene ◽  
Alternate Splicing ◽  
Male And Female ◽  
P Elements ◽  
Male Germline ◽  
Female Germline ◽  
Transposase Expression

Abstract Drosophila were genetically transformed with a hobo transgene that contains a terminally truncated but otherwise complete P element fused to the promoter from the Drosophila hsp70 gene. Insertions of this H(hsp/CP) transgene on either of the major autosomes produced the P transposase in both the male and female germlines, but not in the soma. Heat-shock treatments significantly increased transposase activity in the female germline; in the male germline, these treatments had little effect. The transposase activity of two insertions of the H(hsp/CP) transgene was not significantly greater than their separate activities, and one insertion of this transgene reduced the transposase activity of P(ry+, Δ2-3)99B, a stable P transgene, in the germline as well as in the soma. These observations suggest that, through alternate splicing, the H(hsp/CP) transgene produces a repressor that feeds back negatively to regulate transposase expression or function in both the somatic and germline tissues. The H(hsp/CP) transgenes are able to induce gonadal dysgenesis when the transposase they encode has P-element targets to attack. However, this ability and the ability to induce P-element excisions are repressed by the P cytotype, a chromosomal/cytoplasmic state that regulates P elements in the germline.

scholarly journals The Regulatory Properties of Autonomous Subtelomeric P Elements Are Sensitive to a Suppressor of variegation in Drosophila melanogaster

Genetics ◽  
1996 ◽  
Vol 143 (4) ◽  
pp. 1663-1674 ◽  
Author(s):  
Stéphane Ronsseray ◽  
Monique Lehmann ◽  
Danielle Nouaud ◽  
Dominique Anxolabéhère
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Recombination ◽  
Natural Populations ◽  
P Element ◽  
Single Element ◽  
Heterochromatin Protein 1 ◽  
X Chromosomes ◽  
P Elements ◽  
Associated Sequences ◽  
Regulatory Properties

Abstract Genetic recombination was used in Drosophila melanogaster to isolate P elements, inserted at the telomeres of X chromosomes (cytological site 1A) from natural populations, in a genetic background devoid of other P elements. We show that complete maternally inherited P repression in the germline (P cytotype) can be elicited by only two autonomous P elements at 1A and that a single element at this site has partial regulatory properties. The analysis of the surrounding chromosomal regions of the P elements at 1A shows that in all cases these elements are flanked by Telomeric Associated Sequences, tandemly repetitive noncoding sequences that have properties of heterochromatin. In addition, we show that the regulatory properties of P elements at 1A can be inhibited by some of the mutant alleles of the Su(var)205 gene and by a deficiency of this gene. However, the regulatory properties of reference P strains (Harwich and Texas 007) are not impaired by Su(var)205 mutations. Su(var)205 encodes Heterochromatin Protein 1 (HP1). These results suggest that the HP1 dosage effect on the P element properties is sitedependent and could involve the structure of the chromatin.

Genes Expressed in the Ring Gland, the Major Endocrine Organ of Drosophila melanogaster

Genetics ◽  
1998 ◽  
Vol 149 (1) ◽  
pp. 217-231
Author(s):  
Peter D Harvie ◽  
Maria Filippova ◽  
Peter J Bryant
Keyword(s):  
Reporter Gene ◽  
Translational Regulation ◽  
Developmental Stages ◽  
System Development ◽  
Elongation Factor ◽  
Endocrine System ◽  
Nervous System Development ◽  
Enhancer Trap ◽  
P Element ◽  
Ring Gland

Abstract We have used an enhancer-trap approach to begin characterizing the function of the Drosophila endocrine system during larval development. Five hundred and ten different lethal PZ element insertions were screened to identify those in which a reporter gene within the P element showed strong expression in part or all of the ring gland, the major site of production and release of developmental hormones, and which had a mutant phenotype consistent with an endocrine defect. Nine strong candidate genes were identified in this screen, and eight of these are expressed in the lateral cells of the ring gland that produce ecdysteroid molting hormone (EC). We have confirmed that the genes detected by these enhancer traps are expressed in patterns similar to those detected by the reporter gene. Two of the genes encode proteins, protein kinase A and calmodulin, that have previously been implicated in the signaling pathway leading to EC synthesis and release in other insects. A third gene product, the translational elongation factor EF-1α F1, could play a role in the translational regulation of EC production. The screen also identified the genes couch potato and tramtrack, previously known from their roles in peripheral nervous system development, as being expressed in the ring gland. One enhancer trap revealed expression of the gene encoding the C subunit of vacuolar ATPase (V-ATPase) in the medial cells of the ring gland, which produce the juvenile hormone that controls progression through developmental stages. This could reveal a function of V-ATPase in the response of this part of the ring gland to adenotropic neuropeptides. However, the gene identified by this enhancer trap is ubiquitously expressed, suggesting that the enhancer trap is detecting only a subset of its control elements. The results show that the enhancer trap approach can be a productive way of exploring tissue-specific genetic functions in Drosophila.

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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