gypsy elements occur in two variants - active and inactive. The difference maps to one or both of two amino acid substitutions (T/D and K/R) at the beginning of gypsy\pol. The active form occurs predominantly in strains from recently caught natural populations, and in flam mutants.
gypsy virus-like particles (VLPs) can be carried by D.hydei cell lines DH14 and DH33. The proportion of cells that carry gypsy increase with time. It is unknown whether copies of exogenous gypsy are intergrated into genomic DNA or persist as extrachromosomal circular molecules.
gypsy does not rely on germline expression for its mobilisation. The expression of a gypsy provirus in the maternal soma is necessary and sufficient for its subsequent integration into the germline of the progeny. This soma towards germline transfer appears to be independent of the expression of the gypsy\env gene.
Cell lines carrying the permissive flam1 allele accumulate many nuclear virus-like particles, cytoplasmic dense particles and cisternae filled with fibrous material. Two of three such cell lines have an increased copy number of the gypsy element.
In some stocks active gypsy elements are found restricted to the Y chromosome. The presence of flam alleles tends to be associated with the confinement of active gypsy elements to the Y chromosome. This might be a result of the female-specific effect of flam on gypsy activity.
The length of time the existence of endogenous genomic gypsy was accompanied by host-virus co-evolution is studied. Host-virus co-evolution probably led to the acquisition by flam gene of the ability to control gypsy multiplication.
The expression of gypsy encoded proteins is analysed to explore how gypsy is transmitted between generations. Assembly of gypsy particles is visualised in the follicle cells of flam females by electron microscopy, these observations provide the basis for a novel model to explain how gypsy is transmitted from generation to generation. gypsy virions appear to move through the perivitelline space during a brief developmental window and infect the oocyte, providing a mechanism to explain gypsy insertion in the next generation.
Used in an investigation to address the relationship between retrotransposons and retroviruses and the coadaptation of these retroelements to their host genomes. Results indicate retrotransposons are heterogeneous in contrast to retroviruses, suggesting different modes of evolution by slippage-like mechanisms.
The nucleotide sequence of Dsub\gypsy is determined. A comparative analysis of the sequence and molecular structures of Dsub\gypsy, Dvir\gypsy and gypsy reveals gypsy is the only infectious particle, the other two have lost the ability. gypsy elements are found in D.subobscura natural populations suggesting the populations were invaded by infectious gypsy elements.
Dsub\gypsy, Dvir\gypsy and gypsy show many structural similarities including sequences necessary for transcription and regulatory and coding sequences which suggest a common mechanism of expression. The ORF3 of Dsub\gypsy and Dvir\gypsy lack some motifs essential for the function of the "env-like" protein.
gypsy can be transmitted from flam strains in which it transposes to strains devoid of functional elements by egg plasm transfer or growing "empty" larvae in the presence of homogenized pupae of the flam stock. Transposition of gypsy occurs only in the progeny of females homozygous for permissive alleles of flam, where gypsy transcripts are restricted to the somatic follicle cells in the ovaries. Infectious particles which then infect the oocyte are apparently produced in these cells.
Mapping of gypsy insertions into the ovo gene reveals a global insertion specificity rather than a specificity for a local nucleotide consensus sequence.
The repressive effect of su(Hw) on y2 expression is limited to the chromosome in which the su(Hw) binding sites in gypsy are present. The negative effect of the su(Hw) protein can be transmitted to the gene present on the other homologous paired chromosome in the presence of mod(mdg4) mutations. They allow the su(Hw) protein to act in trans and inhibit the action of the y enhancers located in the homologous chromosome on the promoter of their gene.
Flies infected with the gypsy viral particles isolated from flam females show de novo gypsy mobilization accompanied by the appearance of new mutations. Reversion of various transposable element-induced mutations was also observed at a high frequency. The presence of mutations correlates with the mobilization of transposable elements such as copia, jockey, Stalker, 412 and Tirant.
22% of recessive lethal mutations caused by the insertion of P{SUPor-P}, which contains gypsy\su(Hw)BR sequences, are suppressed by mutations in su(Hw), indicating that they would not have been detected by a standard P-element insertion.
su(Hw) acts as a transcriptional activator of gypsy expression during development. Ecol\lacZ reporter gene constructs containing the su(Hw) binding region upstream suggest that su(Hw) activates the tissue-specific expression of gypsy at the level of transcription initiation. Analysis of specific su(Hw) mutant alleles on the expression of this reporter gene indicate that both the amino terminal acidic and the leucine zipper domains of su(Hw) are essential for the proper regulation of gypsy expression in the larval tissues and adult ovaries. This data suggests that the su(Hw) protein interacts with other proteins through its acidic and leucine zipper domains to produce the tissue-specific expression of gypsy.
The spatial and temporal expression patterns of fifteen families of retrotransposons are analysed during embryogenesis and are found to be conserved. Results suggest that all families carry cis-acting elements that control their spatial and temporal expression patterns.
Genetic instability of the Mutator Strain (MS) system is caused by the combination of two factors: mutations in genes regulating gypsy transposition in Stable Strains (SS) and its MS derivatives, and the presence of transpositionally active gypsy copies in MS but not SS.
gypsy can be transmitted by microinjection of egg plasm from embryos of a strain containing actively transposing gypsy elements into embryos of a strain originally devoid of transposing elements. gypsy is an infectious virus as shown by horizontal transfer when individuals devoid of transposing elements are raised on medium containing ground pupae of a stock containing transposable elements.
Interactions between mod(mdg4) and su(Hw) mutations have been studied by their effect on the phenotypic expression of mutations induced by insertion of a gypsy element.
Heat induced transcription of introduced gypsy constructs and endogenous gypsy elements in Schneider 2 cells causes degradation of pre-existing gypsy transcripts. During recovery from heat shock gypsy transcription is restored but its termination and/or 3'-end processing is aberrant.
Plasmids containing 5' truncated gypsy elements were introduced into D.melanogaster and D.hydei cell lines: appearance of new complete DNA copies with reconstructed 5'LTR were detected by PCR after transient expression and by Southern blot after stable transformation. Two gypsy subfamilies that differ in transpositional activity were found to differ in efficiency of retrotransposition.
Polymorphism of transposable elements in inbred lines has been examined: P-element, gypsy, jockey, I-element, mdg1, 412, mdg3 and 297 sites are largely stable, whereas roo and copia sites are polymorphic.
Mutations at f and c that are dominantly suppressible by su(Hw) mutations are found to be caused by gypsy insertions with molecular alterations in octamer-like-repeat region, proposed to affect the affinity of binding of su(Hw) product to gypsy sequences.
During the course of experiments with genetically unstable MS strains gypsy elements were observed to transpose whereas mdg1 and 412 sites in the X chromosome were unchanged.
One substock of inbred lines shows considerable heterogeneity of insertion sites of copia (frequency of insertions is 12% per haploid genome per generation) whereas mdg1, 412, mdg3, gypsy, 297 and HMS-Beagle were stable in all stocks examined.
Deletion analysis of gypsy (the insertion into y causing y2) demonstrates that the region to which su(Hw) protein binds is required for the generation of the mutant phenotype by gypsy.
Stability of 11 transposable element families compared by Southern blotting among individuals of lines that had been subjected to 30 generations of sister sib matings. 412, roo, blood, 297, 1731 and G-element all appear stable, whereas copia, hobo, I-element, gypsy and jockey elements show instability.
The expression of a number of gypsy-Ecol\CAT reporter constructs has been studied, to locate sequences in the gypsy long terminal repeat that are important for transcription. A 98bp region, from -38 to +60bp, is sufficient for normal level transcription.
gypsy contains a sequence, BaBx, that potentiates upstream polyadenylation sites and it appears to operate at the level of the DNA template. Changes in the repeat motif can reduce both protein binding and poly(A) site potentiation properties of the sequence.
The distribution of a number of transposable elements, including gypsy elements, in a D.melanogaster laboratory strain with a high frequency of spontaneous mutations and its derivatives, has been studied.
gypsy elements from two D.melanogaster strains (one stable and one unstable) have been cloned and analysed. The stable strain contains a small number of gypsy elements with a constant localisation in the chromosomes. The unstable strain contains an increased number of gypsy elements with a higher frequency of transposition.
gypsy has been cloned from two Drosophila strains; a stable strain and an unstable strain characterised by an elevated spontaneous mutation rate. The gypsy elements cloned from the two strains have structural differences allowing them to be subdivided into two subfamilies.
gypsy elements from a single D.melanogaster strain are structurally heterogeneous, consisting of full-length, slightly diverging, and highly diverging gypsy elements.
The gypsy element contains two closely situated regions that bind to proteins from nuclear extracts. One is an imperfect palindrome with homology to the E.coli lac operator and the other is a reiterated sequence with homology to the octamer sequence found in the core of many enhancers and upstream promoter elements. Transient expression of deletion mutants shows that the sequences are negative and positive regulators, respectively, of gypsy transcription. The su(Hw) gene encodes a protein which activates gypsy transcription and the su(f) gene encodes a protein capable of gypsy repression.
First described by Ilyin et al. (1980) as mdg4, a sequence complementary to double stranded RNA from tissue culture cells and by Bender et al. (1983) as an insertion associated with mutations Ubxbx-3, Ubxbx-34e, Ubxbxd-55i and Ubxbxd-51j. Modolell et al. (1983) have shown by in situ hybridization that gypsy insertions are associated with many mutations suppressed by su(Hw). The su(Hw) product binds to an enhancer-like sequence within gypsy and this may affect the expression of adjacent genes as well as of gypsy itself. This is alleviated by su(Hw) mutations (Geyer et al., 1988; Peifer and Bender, 1988; Spana et al., 1988; Mazo et al., 1989). The phenotypes of some mutations caused by gypsy insertions are affected by su(f) mutations. The LTR sequence shown here was reported by Bayev et al. Freund and Meselson (1984) have reported an equivalent sequence of 482 base pairs. The sequences of complete elements have been reported by Yuki et al. and Marlor et al. (1986). The map shown in Lindsley, Zimm, 1992: 1101 is based on those of Bayev et al. and Mattox and Davidson (1984). There are no sites for the enzymes BamHI or SalI.
Other Information
Etymology
External Crossreferences and Linkouts ( 28 )
Crossreferences
GenBank Nucleotide
-
A collection of sequences from several sources, including GenBank, RefSeq, TPA, and PDB.
The single full length gypsy in the sequenced strain is most likely active.
An insertion of P{SUPor-P} into a gypsy has been identified by virtue of decreasing transmission of Dp(1;f)J21A to offspring to 20%.
gypsy elements occur in two variants - active and inactive. The difference maps to one or both of two amino acid substitutions (T/D and K/R) at the beginning of gypsy\pol. The active form occurs predominantly in strains from recently caught natural populations, and in flam mutants.
gypsy virus-like particles (VLPs) can be carried by D.hydei cell lines DH14 and DH33. The proportion of cells that carry gypsy increase with time. It is unknown whether copies of exogenous gypsy are intergrated into genomic DNA or persist as extrachromosomal circular molecules.
gypsy does not rely on germline expression for its mobilisation. The expression of a gypsy provirus in the maternal soma is necessary and sufficient for its subsequent integration into the germline of the progeny. This soma towards germline transfer appears to be independent of the expression of the gypsy\env gene.
Cell lines carrying the permissive flam1 allele accumulate many nuclear virus-like particles, cytoplasmic dense particles and cisternae filled with fibrous material. Two of three such cell lines have an increased copy number of the gypsy element.
In some stocks active gypsy elements are found restricted to the Y chromosome. The presence of flam alleles tends to be associated with the confinement of active gypsy elements to the Y chromosome. This might be a result of the female-specific effect of flam on gypsy activity.
gypsy virus-like particles (VLPs) accumulate inside flam1 follicle cells close to envelope-containing membranes.
The length of time the existence of endogenous genomic gypsy was accompanied by host-virus co-evolution is studied. Host-virus co-evolution probably led to the acquisition by flam gene of the ability to control gypsy multiplication.
The expression of gypsy encoded proteins is analysed to explore how gypsy is transmitted between generations. Assembly of gypsy particles is visualised in the follicle cells of flam females by electron microscopy, these observations provide the basis for a novel model to explain how gypsy is transmitted from generation to generation. gypsy virions appear to move through the perivitelline space during a brief developmental window and infect the oocyte, providing a mechanism to explain gypsy insertion in the next generation.
Used in an investigation to address the relationship between retrotransposons and retroviruses and the coadaptation of these retroelements to their host genomes. Results indicate retrotransposons are heterogeneous in contrast to retroviruses, suggesting different modes of evolution by slippage-like mechanisms.
The nucleotide sequence of Dsub\gypsy is determined. A comparative analysis of the sequence and molecular structures of Dsub\gypsy, Dvir\gypsy and gypsy reveals gypsy is the only infectious particle, the other two have lost the ability. gypsy elements are found in D.subobscura natural populations suggesting the populations were invaded by infectious gypsy elements.
Dsub\gypsy, Dvir\gypsy and gypsy show many structural similarities including sequences necessary for transcription and regulatory and coding sequences which suggest a common mechanism of expression. The ORF3 of Dsub\gypsy and Dvir\gypsy lack some motifs essential for the function of the "env-like" protein.
Multiplication of gypsy in the germline is under the control of flam.
gypsy can be transmitted from flam strains in which it transposes to strains devoid of functional elements by egg plasm transfer or growing "empty" larvae in the presence of homogenized pupae of the flam stock. Transposition of gypsy occurs only in the progeny of females homozygous for permissive alleles of flam, where gypsy transcripts are restricted to the somatic follicle cells in the ovaries. Infectious particles which then infect the oocyte are apparently produced in these cells.
The distribution of gypsy elements in heterochromatin has been studied by in situ hybridisation to mitotic chromosomes.
Mapping of gypsy insertions into the ovo gene reveals a global insertion specificity rather than a specificity for a local nucleotide consensus sequence.
The repressive effect of su(Hw) on y2 expression is limited to the chromosome in which the su(Hw) binding sites in gypsy are present. The negative effect of the su(Hw) protein can be transmitted to the gene present on the other homologous paired chromosome in the presence of mod(mdg4) mutations. They allow the su(Hw) protein to act in trans and inhibit the action of the y enhancers located in the homologous chromosome on the promoter of their gene.
Flies infected with the gypsy viral particles isolated from flam females show de novo gypsy mobilization accompanied by the appearance of new mutations. Reversion of various transposable element-induced mutations was also observed at a high frequency. The presence of mutations correlates with the mobilization of transposable elements such as copia, jockey, Stalker, 412 and Tirant.
Mature gypsy particles are produced in the context of the flam mutation, which derepresses gypsy env production.
The distribution of a number of transposable elements has been studied in 10 Harwich mutation accumulation lines.
The distribution of transposable elements within heterochromatin indicates that they are major structural components of the heterochromatin.
The chromosomal flam locus controls the infective properties of gypsy.
22% of recessive lethal mutations caused by the insertion of P{SUPor-P}, which contains gypsy\su(Hw)BR sequences, are suppressed by mutations in su(Hw), indicating that they would not have been detected by a standard P-element insertion.
su(Hw) acts as a transcriptional activator of gypsy expression during development. Ecol\lacZ reporter gene constructs containing the su(Hw) binding region upstream suggest that su(Hw) activates the tissue-specific expression of gypsy at the level of transcription initiation. Analysis of specific su(Hw) mutant alleles on the expression of this reporter gene indicate that both the amino terminal acidic and the leucine zipper domains of su(Hw) are essential for the proper regulation of gypsy expression in the larval tissues and adult ovaries. This data suggests that the su(Hw) protein interacts with other proteins through its acidic and leucine zipper domains to produce the tissue-specific expression of gypsy.
The distribution of gypsy elements across the chromosomes has been analysed in individuals from a natural population of D.melanogaster.
The spatial and temporal expression patterns of fifteen families of retrotransposons are analysed during embryogenesis and are found to be conserved. Results suggest that all families carry cis-acting elements that control their spatial and temporal expression patterns.
Genetic instability of the Mutator Strain (MS) system is caused by the combination of two factors: mutations in genes regulating gypsy transposition in Stable Strains (SS) and its MS derivatives, and the presence of transpositionally active gypsy copies in MS but not SS.
gypsy can be transmitted by microinjection of egg plasm from embryos of a strain containing actively transposing gypsy elements into embryos of a strain originally devoid of transposing elements. gypsy is an infectious virus as shown by horizontal transfer when individuals devoid of transposing elements are raised on medium containing ground pupae of a stock containing transposable elements.
Comparisons between gypsy sequences in D.melanogaster, D.subobscura and D.virilis strongly suggest that gypsy sequences have been horizontally transferred between these species.
Interactions between mod(mdg4) and su(Hw) mutations have been studied by their effect on the phenotypic expression of mutations induced by insertion of a gypsy element.
Heat induced transcription of introduced gypsy constructs and endogenous gypsy elements in Schneider 2 cells causes degradation of pre-existing gypsy transcripts. During recovery from heat shock gypsy transcription is restored but its termination and/or 3'-end processing is aberrant.
Plasmids containing 5' truncated gypsy elements were introduced into D.melanogaster and D.hydei cell lines: appearance of new complete DNA copies with reconstructed 5'LTR were detected by PCR after transient expression and by Southern blot after stable transformation. Two gypsy subfamilies that differ in transpositional activity were found to differ in efficiency of retrotransposition.
gypsy and Dvir\gypsy virus-like particles (VLP) are present in the cultured media from D.melanogaster and D.virilis.
Polymorphism of transposable elements in inbred lines has been examined: P-element, gypsy, jockey, I-element, mdg1, 412, mdg3 and 297 sites are largely stable, whereas roo and copia sites are polymorphic.
Mutations at f and c that are dominantly suppressible by su(Hw) mutations are found to be caused by gypsy insertions with molecular alterations in octamer-like-repeat region, proposed to affect the affinity of binding of su(Hw) product to gypsy sequences.
During the course of experiments with genetically unstable MS strains gypsy elements were observed to transpose whereas mdg1 and 412 sites in the X chromosome were unchanged.
Numbers of mdg1, mdg3, gypsy and copia have been studied in several strains of D.melanogaster and D.simulans. Mean number of mdg1 and copia sites are drastically reduced in D.simulans. Majority of mdg1 and copia sites, and one third of mdg3 sites, are in hot spots for insertion, particularly in D.simulans. Southern blot analysis indicates that the majority of mdg1 and copia are in the euchromatin of D.melanogaster but the heterochromatin of D.simulans.
One substock of inbred lines shows considerable heterogeneity of insertion sites of copia (frequency of insertions is 12% per haploid genome per generation) whereas mdg1, 412, mdg3, gypsy, 297 and HMS-Beagle were stable in all stocks examined.
Deletion analysis of gypsy (the insertion into y causing y2) demonstrates that the region to which su(Hw) protein binds is required for the generation of the mutant phenotype by gypsy.
Stability of 11 transposable element families compared by Southern blotting among individuals of lines that had been subjected to 30 generations of sister sib matings. 412, roo, blood, 297, 1731 and G-element all appear stable, whereas copia, hobo, I-element, gypsy and jockey elements show instability.
The expression of a number of gypsy-Ecol\CAT reporter constructs has been studied, to locate sequences in the gypsy long terminal repeat that are important for transcription. A 98bp region, from -38 to +60bp, is sufficient for normal level transcription.
A Dvir\gypsy element has been cloned and sequenced, and compared with D.melanogaster gypsy.
gypsy contains a sequence, BaBx, that potentiates upstream polyadenylation sites and it appears to operate at the level of the DNA template. Changes in the repeat motif can reduce both protein binding and poly(A) site potentiation properties of the sequence.
The distribution of a number of transposable elements, including gypsy elements, in a D.melanogaster laboratory strain with a high frequency of spontaneous mutations and its derivatives, has been studied.
gypsy elements from two D.melanogaster strains (one stable and one unstable) have been cloned and analysed. The stable strain contains a small number of gypsy elements with a constant localisation in the chromosomes. The unstable strain contains an increased number of gypsy elements with a higher frequency of transposition.
gypsy has been cloned from two Drosophila strains; a stable strain and an unstable strain characterised by an elevated spontaneous mutation rate. The gypsy elements cloned from the two strains have structural differences allowing them to be subdivided into two subfamilies.
gypsy poly(A)+ RNA is not detected in the stable strain, although a high level of gypsy transcription is observed in the unstable strain.
The distribution of gypsy elements in a mutator strain of D.melanogaster and its derivatives has been studied.
gypsy elements from a single D.melanogaster strain are structurally heterogeneous, consisting of full-length, slightly diverging, and highly diverging gypsy elements.
The gypsy element contains two closely situated regions that bind to proteins from nuclear extracts. One is an imperfect palindrome with homology to the E.coli lac operator and the other is a reiterated sequence with homology to the octamer sequence found in the core of many enhancers and upstream promoter elements. Transient expression of deletion mutants shows that the sequences are negative and positive regulators, respectively, of gypsy transcription. The su(Hw) gene encodes a protein which activates gypsy transcription and the su(f) gene encodes a protein capable of gypsy repression.
Nucleotide position -118 of the ct locus is a hotspot for gypsy element insertions.
First described by Ilyin et al. (1980) as mdg4, a sequence complementary to double stranded RNA from tissue culture cells and by Bender et al. (1983) as an insertion associated with mutations Ubxbx-3, Ubxbx-34e, Ubxbxd-55i and Ubxbxd-51j. Modolell et al. (1983) have shown by in situ hybridization that gypsy insertions are associated with many mutations suppressed by su(Hw). The su(Hw) product binds to an enhancer-like sequence within gypsy and this may affect the expression of adjacent genes as well as of gypsy itself. This is alleviated by su(Hw) mutations (Geyer et al., 1988; Peifer and Bender, 1988; Spana et al., 1988; Mazo et al., 1989). The phenotypes of some mutations caused by gypsy insertions are affected by su(f) mutations. The LTR sequence shown here was reported by Bayev et al. Freund and Meselson (1984) have reported an equivalent sequence of 482 base pairs. The sequences of complete elements have been reported by Yuki et al. and Marlor et al. (1986). The map shown in Lindsley, Zimm, 1992: 1101 is based on those of Bayev et al. and Mattox and Davidson (1984). There are no sites for the enzymes BamHI or SalI.