Copy number control of a transposable element, the I factor, a LINE-like element in Drosophila

ABSTRACT Transposition of Tn5 in Escherichia coli strains containing one or multiple copies of the transposable element was investigated. It was found that the overall frequency of transposition within a cell remained constant regardless of the number of copies of Tn5 present in that cell. Experiments measuring the transposition frequency of differentially marked Tn5s confirmed that the frequency of transposition of an individual Tn5 decreased proportionally with the total number of copies of the element present in a cell. The IS50R-encoded function, protein 2, which has previously been shown to be an inhibitor of transposition, is sufficient to mediate this inhibitory effect. The concentration of protein 2 in a cell appears to modulate the transposition of individual Tn5 elements in such a way that the overall transposition of Tn5 in a cell remains constant.

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Conformational changes induced by integration host factor at origin gamma of R6K and copy number control

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)98497-8 ◽

1991 ◽

Vol 266 (24) ◽

pp. 15924-15937

Author(s):

W.L. Kelley ◽

D. Bastia

Keyword(s):

Conformational Changes ◽

Copy Number ◽

Integration Host Factor ◽

Host Factor ◽

Copy Number Control

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The Structure and Paramutagenicity of the R-marbled Haplotype of Zea mays

Genetics ◽

10.1093/genetics/153.2.979 ◽

1999 ◽

Vol 153 (2) ◽

pp. 979-991 ◽

Cited By ~ 3

Author(s):

Tadas Panavas ◽

Jessica Weir ◽

Elsbeth L Walker

Keyword(s):

Zea Mays ◽

Transposable Element ◽

Copy Number ◽

Gene Copy Number ◽

Gene Copy ◽

Crossing Over ◽

Direct Repeats ◽

Pigmentation Pattern ◽

R1 Gene ◽

Distal Gene

Abstract Paramutation is the meiotically heritable silencing of a gene that can occur in particular heterozygous combinations. The R-marbled (R-mb) haplotype is paramutagenic: it causes paramutable r1 haplotypes like R-r to become heritably silenced. R-mb was found to comprise three distinct r1 genes arranged as direct repeats. The most distal gene of R-mb, Scm, contains a novel transposable element, Shooter (Sho). Excision of the Sho element early in aleurone development results in the characteristic “marbled” aleurone pigmentation pattern conferred by R-mb. The effect of gene copy number on the paramutagenic strength of R-mb was tested. Paramutagenic strength of R-mb is directly correlated with r1 gene copy number. Paramutagenic strength of R-mb is directly correlated with r1 gene copy number. Paramutagenic strength of R-mb was not affected by removal, through crossing over, of the Sho transposon. Finally, R-mb does not appear to contain the transposable element, Doppia, which is associated with paramutability of R-r, and has been suggested to play a role in paramutagenicity of another paramutagenic haplotype, R-stippled.

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A LINE-like transposable element in Drosophila, the I factor, encodes a protein with properties similar to those of retroviral nucleocapsids

The EMBO Journal ◽

10.1093/emboj/16.14.4448 ◽

1997 ◽

Vol 16 (14) ◽

pp. 4448-4455 ◽

Cited By ~ 38

Author(s):

A. Dawson

Keyword(s):

Transposable Element ◽

I Factor

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Hypothesis: hypersensitive plasmid copy number control for ColE1

Biophysical Journal ◽

10.1016/s0006-3495(96)79555-3 ◽

1996 ◽

Vol 70 (1) ◽

pp. 135-145 ◽

Cited By ~ 9

Author(s):

M. Ehrenberg

Keyword(s):

Copy Number ◽

Plasmid Copy Number ◽

Plasmid Copy ◽

Copy Number Control

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Broad Host-Range Plasmid R1162: Replication, Incompatibility, and Copy-Number Control

Plasmids in Bacteria ◽

10.1007/978-1-4613-2447-8_16 ◽

1985 ◽

pp. 173-188 ◽

Cited By ~ 3

Author(s):

Richard J. Meyer ◽

Lung-Shen Lin ◽

Kyunghoon Kim ◽

Michael A. Brasch

Keyword(s):

Host Range ◽

Copy Number ◽

Broad Host Range ◽

Copy Number Control ◽

Broad Host Range Plasmid

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Direct determination of retrotransposon transposition rates in Drosophila melanogaster

Genetics Research ◽

10.1017/s0016672300032249 ◽

1994 ◽

Vol 63 (2) ◽

pp. 139-144 ◽

Cited By ~ 34

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.

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Post-transcriptional Cosuppression of Ty1 Retrotransposition

Genetics ◽

10.1093/genetics/165.1.83 ◽

2003 ◽

Vol 165 (1) ◽

pp. 83-99

Author(s):

David J Garfinkel ◽

Katherine Nyswaner ◽

Jun Wang ◽

Jae-Yong Cho

Keyword(s):

Gene Silencing ◽

Reverse Transcription ◽

Copy Number ◽

Transcript Level ◽

Gag Protein ◽

Protein Levels ◽

Copy Number Control ◽

Gal1 Promoter ◽

Pgk1 Promoter ◽

Ty1 Retrotransposition

Abstract To determine whether homology-dependent gene silencing or cosuppression mechanisms underlie copy number control (CNC) of Ty1 retrotransposition, we introduced an active Ty1 element into a naïve strain. Single Ty1 element retrotransposition was elevated in a Ty1-less background, but decreased dramatically when additional elements were present. Transcription from the suppressing Ty1 elements enhanced CNC but translation or reverse transcription was not required. Ty1 CNC occurred with a transcriptionally active Ty2 element, but not with Ty3 or Ty5 elements. CNC also occurred when the suppressing Ty1 elements were transcriptionally silenced, fused to the constitutive PGK1 promoter, or contained a minimal segment of mostly TYA1-gag sequence. Ty1 transcription of a multicopy element expressed from the GAL1 promoter abolished CNC, even when the suppressing element was defective for transposition. Although Ty1 RNA and TyA1-gag protein levels increased with the copy number of expressible elements, a given element's transcript level varied less than twofold regardless of whether the suppressing elements were transcriptionally active or repressed. Furthermore, a decrease in the synthesis of Ty1 cDNA is strongly associated with Ty1 CNC. Together our results suggest that Ty1 cosuppression can occur post-transcriptionally, either prior to or during reverse transcription.

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