scholarly journals Transmission pattern of hobo transposable element in transgenic lines of Drosophila melanogaster

1998 ◽  
Vol 71 (2) ◽  
pp. 97-107 ◽  
Author(s):  
VERONIQUE LADEVEZE ◽  
IBO GALINDO ◽  
NICOLE CHAMINADE ◽  
LUIS PASCUAL ◽  
GEORGES PERIQUET ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Population Studies ◽  
Insertion Site ◽  
Molecular Analyses ◽  
Transgenic Lines ◽  
Genomic Dnas ◽  
Insertion Sites ◽  
Method Show

This study is an attempt to trace the fate of hobo elements in the genomes of E strains of Drosophila melanogaster that have been transfected with pHFL1, a plasmid containing an autonomous hobo. Such long-term population studies (over 105 generations) could be very useful for better understanding the population and genomic dynamics of transposable elements and their pattern of insertions. Molecular analyses of hobo elements in the transfected lines were performed using Southern blots of XhoI-digested genomic DNAs. The complete element was observed in all six injected lines. In two lines we observed, at generation 100, two deleted elements, which did not correspond to Th1 and Th2. The results obtained by the in situ method show that the number of hybridization sites increases in each line and prove that the hobo element may be amplified in an RM genome. The hobo activity does not seem to be systematically correlated with the number of hobo elements. After generation 85, the evolution of the hobo element's insertion site number depends on the injected line. In all lines, the total number of insertions remains quite small, between 0 and 11. Hobo elements are located on each of the chromosomal arms. We describe ‘hotspots’ – insertion sites present in all lines and in all generations. On the 3R arm, a short inversion appeared once at generation 85.

scholarly journals Direct determination of retrotransposon transposition rates in Drosophila melanogaster

1994 ◽  
Vol 63 (2) ◽  
pp. 139-144 ◽  
Author(s):  
Sergey V. Nuzhdin ◽  
Trudy F. C. Mackay
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Element ◽  
Inbred Line ◽  
Copy Number ◽  
Direct Determination ◽  
Hybridization Analysis ◽  
Spontaneous Mutations ◽  
Insertion Sites

SummaryRates of transposition and excision of the Drosophila melanogaster retrotransposon elements mdg3, 297, Doc, roo and copia were estimated directly, by in situ hybridization analysis of their cytological insertion sites in 31 replicates of a highly inbred line that had accumulated spontaneous mutations for approximately 160generations. Estimated transposition rates of Doc, roo and copia were, respectively, 4·2 × 10−5, 3·1 × 10−3 and 1·3 − 10−3; no transpositions of 297 nor mdg3 were observed. Rates of transposition of copia varied significantly among sublines. Excisions were only observed for roo elements, at a rate of 9·0 × 10−6 per element per generation. Copy number averaged over these element families increased 5·9 %; therefore, in these lines the magnitude of the forces opposing transposable element multiplication were weaker than transposition rates.

scholarly journals Rates of movement of transposable elements on the second chromosome of Drosophila melanogaster

2000 ◽  
Vol 75 (3) ◽  
pp. 275-284 ◽  
Author(s):  
XULIO MASIDE ◽  
STAVROULA ASSIMACOPOULOS ◽  
BRIAN CHARLESWORTH
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Elements ◽  
Polytene Chromosomes ◽  
Mutation Accumulation ◽  
Long Terminal Repeats ◽  
Significant Difference ◽  
Transposable Element Copy ◽  
Excision Rate

The rates of movement of 11 families of transposable elements of Drosophila melanogaster were studied by means of in situ hybridization of probes to polytene chromosomes of larvae from a long-term mutation accumulation experiment. Replicate mutation-accumulation lines carrying second chromosomes derived from a single common ancestral chromosome were maintained by backcrosses of single males heterozygous for a balancer chromosome and a wild-type chromosome, and were scored after 116 generations. Twenty-seven transpositions and 1 excision were detected using homozygous viable and fertile second chromosomes, for a total of 235056 potential sources of transposition events and a potential 252880 excision events. The overall transposition rate per element per generation was 1·15×10−4 and the excision rate was 3·95×10−6. The single excision (of a roo element) was due to recombination between the element's long terminal repeats. A survey of the five most active elements among nine homozygous lethal lines revealed no significant difference in the estimates of transposition and excision rates from those from viable lines. The excess of transposition over excision events is in agreement with the results of other in situ hybridization experiments, and supports the conclusion that replicative increase in transposable element copy number is opposed by selection. These conclusions are compared with those from other studies, and with the conclusions from population surveys of element frequencies.

scholarly journals Genetic and molecular analyses of vgal: a spontaneous and unstable mutation at the vestigial locus in Drosophila melanogaster

1991 ◽  
Vol 57 (3) ◽  
pp. 235-243 ◽  
Author(s):  
Claude Bazin ◽  
Françoise Lemeunier ◽  
Georges Periquet ◽  
Joël Silber
Keyword(s):  
Drosophila Melanogaster ◽  
Low Temperature ◽  
Germ Line ◽  
The Other ◽  
Wild Type ◽  
Male Germ Line ◽  
Molecular Analyses ◽  
Dna Insertion ◽  
Unstable Mutation

SummaryWe describe herein, a new unstable mutant of the vestigial locus, isolated from a French natural population. From this mutant vestigialalmost (vgal) wild-type flies (vgal+) and extreme vg phenotypes (vge) arose spontaneously without genomic shock. The occurrence of vgal+ or vge alleles depends mostly on the breeding temperature; vgal+ revertants arose principally at low temperature (21 °C) and vge at 28 °C. These events occur mainly in the male germ line and the phenomenon appears to be premeiotic. Our results with in situ hybridization experiments and Southern blots show that the vgal mutation is due to a 2 kb DNA insertion, which is a deleted hobo element. Genetic and molecular analyses show that two distinct events may underly the wild-type revertants. One is the excision of the resident hobo element, the other a further deletion (about 300 bp in the example characterized herein). The vge mutation is probably due to a deletion of vestigial sequences flanking the hobo insertion.

scholarly journals Selection against transposable elements in D. simulans and D. melanogaster

1996 ◽  
Vol 68 (1) ◽  
pp. 9-15 ◽  
Author(s):  
C. Vieira ◽  
C. Biémont
Keyword(s):  
In Situ Hybridization ◽  
Transposable Elements ◽  
Copy Number ◽  
Insertion Site ◽  
Natural Populations ◽  
Lower Proportion ◽  
Major Mechanism ◽  
Insertion Sites ◽  
Copy Number Regulation

SummaryThe insertion site numbers of the transposable elements (TEs) copia, mdgl, 412 and gypsy were determined in various natural populations of Drosophila melanogaster and D. simulans by in situ hybridization. We showed that, while all elements except gypsy had many insertion sites scattered over the chromosomes in D. melanogaster, only the 412 element in D. simulans presented a high number of insertions, and this number was lower than in D. melanogaster. This low 412 site number per genome in D. simulans was associated with a lower proportion of insertions on the X chromosome in comparison with D. melanogaster, as determined in diploid genomes (0·090 for D. simulans against 0·137 for D. melanogaster) and in haploid genomes (0·102 against 0·146), each value being, moreover, lower than the value of 0·20 expected on the hypothesis of no selection against insertional mutations. These results suggest that selection is a major mechanism explaining 412 copy number regulation in Drosophila, and is stronger in D. simulans than in D. melanogaster.

scholarly journals Mapping Transgene Insertion Sites Reveals Complex Interactions Between Mouse Transgenes and Neighboring Endogenous Genes

2018 ◽  
Author(s):  
Mallory A. Laboulaye ◽  
Xin Duan ◽  
Mu Qiao ◽  
Irene E. Whitney ◽  
Joshua R. Sanes
Keyword(s):  
Integration Site ◽  
Insertion Site ◽  
Cell Types ◽  
Regulatory Elements ◽  
Endogenous Gene ◽  
Complex Interactions ◽  
Distinct Cell ◽  
Transgenic Lines ◽  
Endogenous Genes ◽  
Insertion Sites

ABSTRACTTransgenic mouse lines are routinely employed to label and manipulate distinct cell types. The transgene generally comprises cell-type specific regulatory elements linked to a cDNA encoding a reporter or other proteins. However, off-target expression seemingly unrelated to the regulatory elements in the transgene is often observed, and sometimes suspected to reflect influences related to the site of transgene integration in the genome. To test this hypothesis, we used a proximity ligation-based method, Targeted Locus Amplification (TLA), to map the insertion sites of three well-characterized transgenes that appeared to exhibit insertion site-dependent expression in retina. The nearest endogenous genes to transgenes HB9-GFP, Mito-P, and TYW3 are Cdh6, Fat4 and Khdrbs2, respectively. For two lines, we demonstrate that expression reflects that of the closest endogenous gene (Fat4 and Cdh6), even though the distance between transgene and endogenous gene is 550 and 680 kb, respectively. In all three lines, the transgenes decrease expression of the neighboring endogenous genes. In each case, the affected endogenous gene was expressed in at least some of the cell types that the transgenic line has been used to mark and study. These results provide insights into the effects of transgenes and endogenous genes on each other’s expression, demonstrate that mapping insertion site is valuable for interpreting results obtained with transgenic lines, and indicate that TLA is a reliable method for integration site discovery.

scholarly journals Long-term evolution of the roo transposable element copy number in mutation accumulation lines of Drosophila melanogaster

2011 ◽  
Vol 93 (3) ◽  
pp. 181-187 ◽  
Author(s):  
JULIA DÍAZ-GONZÁLEZ ◽  
J. FERNANDO VÁZQUEZ ◽  
JESÚS ALBORNOZ ◽  
ANA DOMÍNGUEZ
Keyword(s):  
Drosophila Melanogaster ◽  
De Novo ◽  
Accumulation Rate ◽  
Mutation Accumulation ◽  
Fundamental Parameter ◽  
Highly Active ◽  
Transposition Rate ◽  
Transposable Element Copy

SummaryThe rate of insertion of transposable elements (TEs) is a fundamental parameter to understand both their dynamics and role in the evolution of the eukaryotic genome. Nonetheless, direct estimates of insertion rates are scarce because transposition is in general a rare phenomenon. A great deal of our previous work on transposition was based on a set of long-term mutation accumulation (MA) lines of Drosophila melanogaster started in 1987 (Oviedo lines), where roo was found highly active, with a rate of insertion of 7×10−4 insertions per element and generation, as compared with other 15 TE families that presented transposition rates around 10−5. Here, we study the evolution of the roo transposition rate, by in situ hybridization, after 60–75 additional generations of MA in two subsets of the Oviedo lines, O and O′, which had achieved average numbers of roo insertions of 77 and 84, respectively. In the O lines, insertions accumulated at a rate that remained constant (7×10−4 insertions per element and generation); however, the subset of lines O′ showed a lower accumulation rate of 4×10−4 insertions per element per generation, suggesting a regulation of transposition that depends on the number of elements. However, one of the O′ lines reached a number of 103 insertions, departing from the group mean by 4·6 sd, and showing that it escapes regulation. Hence, ‘de novo’ mutations affecting the regulation of transposition are relatively common. These results are discussed in relation to the possible mechanisms of containment of TEs.

scholarly journals Transposable element-induced response to artificial selection in Drosophila melanogaster: molecular analysis of selection lines.

Genetics ◽  
1990 ◽  
Vol 125 (4) ◽  
pp. 803-811 ◽  
Author(s):  
A E Shrimpton ◽  
T F Mackay ◽  
A J Brown
Keyword(s):  
Drosophila Melanogaster ◽  
Artificial Selection ◽  
Genetic Variance ◽  
Selection Response ◽  
P Element ◽  
Induced Response ◽  
Phenotypic Variance ◽  
P Elements ◽  
Insertion Sites

Abstract Artificial selection lines for abdominal bristle score of Drosophila melanogaster established from P-M hybrid dysgenic crosses showed increases in selection response, heritability and phenotypic variance compared to similar lines started from nondysgenic crosses. To determine whether this increased genetic variance could be due to enhanced transposition of P elements following the dysgenic cross, the cytological locations (sites) of P elements were determined by in situ hybridization for the whole genome of samples of 20 individuals from the parental P strain, 20 individuals from each of the eight dysgenic selection lines, and ten individuals from each of the eight nondysgenic selection lines. Variation among and within the selection lines and the parental P strain in P element insertion sites was exceptionally high. A total of 601 sites were identified, but there was no difference in total number of sites per line, mean number of sites per individual, mean copy number per individual, or site frequency between dysgenic and nondysgenic selection lines, or between lines selected for high and low bristle score. Transposition following nondysgenic crosses may explain additional observations of accelerated selection responses in nondysgenic selection lines. It was not possible to deduce which, if any, of the several hundred insertions in the dysgenic selection lines were responsible for their extreme bristle phenotypes.

scholarly journals Dynamics of the hobo transposable element in transgenic lines of Drosophila melanogaster

2001 ◽  
Vol 77 (2) ◽  
pp. 135-142 ◽  
Author(s):  
V. LADEVEZE ◽  
S. AULARD ◽  
N. CHAMINADE ◽  
C. BIEMONT ◽  
G. PERIQUET ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Element ◽  
High Frequency ◽  
Chromosomal Distribution ◽  
Extensive Survey ◽  
Transgenic Lines ◽  
Insertion Sites ◽  
Selection For ◽  
Genomic Regions ◽  
The Impact

The impact of the hobo transposable element in global reorganization of the Drosophila melanogaster genome has been investigated in transgenic lines generated by injection of hobo elements into the Hikone strain, which lacked them. In the present extensive survey, the chromosomal distribution of hobo insertion sites in the line 28 was found to be homogeneous and similar for all chromosomal arms, except 3L, when compared with other transgenic lines. However, some original features were observed in this line at the genetic and chromosomal levels. Several hotspots of insertion sites were observed on the X, second and third chromosomes. Five sites with a high frequency of hobo insertions were present on the 3L arm in most individuals tested, suggesting the action of selection for hobo element in some sites. The presence of doublets or triplet was also observed, implying that hobo inserts can show local jumps or insertions in preferred regions. This local transposition occurred independently in 11 specific genomic regions in many individuals and generations. The dynamics of this phenomenon were analysed across generations. These results support the use of the hobo system as an important tool in fundamental and applied Drosophila genetics.

The DSC1 Channel, Encoded by the smi60E Locus, Contributes to Odor-Guided Behavior in Drosophila melanogaster

Genetics ◽  
2002 ◽  
Vol 161 (4) ◽  
pp. 1507-1516 ◽  
Author(s):  
Nalini H Kulkarni ◽  
Akihiko H Yamamoto ◽  
Kellie O Robinson ◽  
Trudy F C Mackay ◽  
Robert R H Anholt
Keyword(s):  
Drosophila Melanogaster ◽  
Neuronal Excitability ◽  
Insertion Site ◽  
Antennal Segment ◽  
P Element ◽  
Gene Encoding ◽  
Olfactory Organs ◽  
Nested Gene ◽  
Maxillary Palps

Abstract Previously, we generated P-element insert lines in Drosophila melanogaster with impaired olfactory behavior. One of these smell-impaired (smi) mutants, smi60E, contains a P[lArB] transposon in the second intron of the dsc1 gene near a nested gene encoding the L41 ribosomal protein. The dsc1 gene encodes an ion channel of unknown function homologous to the paralytic (para) sodium channel, which mediates neuronal excitability. Complementation tests between the smi60E mutant and several EP insert lines map the smellimpaired phenotype to the P[lArB] insertion site. Wild-type behavior is restored upon P-element excision. Evidence that reduction in DSC1 rather than in L41 expression is responsible for the smell-impaired phenotype comes from a phenotypic revertant in which imprecise P-element excision restores the DSC1 message while further reducing L41 expression. Behavioral assays show that a threefold decrease in DSC1 mRNA is accompanied by a threefold shift in the dose response for avoidance of the repellent odorant, benzaldehyde, toward higher odorant concentrations. In situ hybridization reveals widespread expression of the dsc1 gene in the major olfactory organs, the third antennal segment and the maxillary palps, and in the CNS. These results indicate that the DSC1 channel contributes to processing of olfactory information during the olfactory avoidance response.

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