scholarly journals Cloning of the Mutator transposable element MuA2, a putative regulator of somatic mutability of the a1-Mum2 allele in maize.

Genetics ◽  
1991 ◽  
Vol 129 (3) ◽  
pp. 845-854 ◽  
Author(s):  
M M Qin ◽  
D S Robertson ◽  
A H Ellingboe
Keyword(s):  
Transposable Elements ◽  
Transposable Element ◽  
Copy Number ◽  
Inverted Repeats ◽  
Terminal Inverted Repeats ◽  
Somatic Instability ◽  
Mutator Activity ◽  
Element System ◽  
Lines Of Evidence

Abstract The identification of the autonomous or transposase-encoding element of the Mutator (Mu) transposable element system of maize is necessary to the characterization of the system. We reported previously that a transcript homologous to the internal region of the MuA element is associated with activity of the Mutator system. We describe here the cloning of another Mu element, designated MuA2, that cosegregates with Mutator activity as assayed by somatic instability of the a1-Mum2 allele. The MuA2 element has features typical of the transposable elements of the Mutator family, including the 210-bp terminal inverted repeats. Several lines of evidence suggest that MuA2 is an autonomous or transposase-encoding element of the Mu family: (1) MuA2 cosegregates with a genetically defined element that regulates somatic mutability of the a1-Mum2 allele; (2) MuA2 is hypomethylated while most other MuA2-hybridizing sequences in the genome are extensively methylated; (3) the increase of the copy number of MuA2 is concomitant with the increase of regulator elements; (4) MuA2-like elements are found in Mutator lines but not in non-Mutator inbreds. We propose that autonomous or transposase-encoding elements of the Mu family may be structurally conserved and MuA2-like.

scholarly journals Identification of a regulatory transposon that controls the Mutator transposable element system in maize.

Genetics ◽  
1991 ◽  
Vol 129 (1) ◽  
pp. 261-270 ◽  
Author(s):  
P Chomet ◽  
D Lisch ◽  
K J Hardeman ◽  
V L Chandler ◽  
M Freeling
Keyword(s):  
Transposable Elements ◽  
Transposable Element ◽  
Restriction Fragment ◽  
Distinct Element ◽  
Single Locus ◽  
Inverted Repeats ◽  
Terminal Inverted Repeats ◽  
Mutator Activity ◽  
Element System ◽  
Multiple Copies

Abstract The Mutator system of maize consists of more than eight different classes of transposable elements each of which can be found in multiple copies. All Mu elements share the approximately 220-bp terminal inverted repeats, whereas each distinct element class is defined by its unique internal sequences. The regulation of instability of this system has been difficult to elucidate due to its multigenic inheritance. Here we present genetic experiments which demonstrate that there is a single locus, MuR1, which can regulate the transposition of Mu1 elements. We describe the cloning of members of a novel class of Mu elements, MuR, and demonstrate that a member of the class is the regulator of Mutator activity, MuR1. This conclusion is based on several criteria: MuR1 activity and a MuR-homologous restriction fragment cosegregate; when MuR1 undergoes a duplicative transposition, an additional MuR restriction fragment is observed, and MuR1 activity and the cosegregating MuR fragment are simultaneously lost within clonal somatic sectors. In addition, the MuR element hybridizes to transcripts in plants with Mutator activity. Our genetic experiments demonstrate that the MuR1 transposon is necessary to specify Mutator activity in our lines.

scholarly journals Identification and Characterization of Transposable Elements of Paracoccus pantotrophus

2003 ◽  
Vol 185 (13) ◽  
pp. 3753-3763 ◽  
Author(s):  
Dariusz Bartosik ◽  
Marta Sochacka ◽  
Jadwiga Baj
Keyword(s):  
Comparative Analysis ◽  
Transposable Elements ◽  
Copy Number ◽  
Inverted Repeats ◽  
Insertion Sequences ◽  
Terminal Inverted Repeats ◽  
Paracoccus Pantotrophus ◽  
Different Strains ◽  
Identification And Characterization

ABSTRACT We studied diversity and distribution of transposable elements residing in different strains (DSM 11072, DSM 11073, DSM 65, and LMD 82.5) of a soil bacterium Paracoccus pantotrophus (α-Proteobacteria). With application of a shuttle entrapment vector pMEC1, several novel insertion sequences (ISs) and transposons (Tns) have been identified. They were sequenced and subjected to detailed comparative analysis, which allowed their characterization (i.e., identification of transposase genes, terminal inverted repeats, as well as target sequences) and classification into the appropriate IS or Tn families. The frequency of transposition of these elements varied and ranged from 10−6 to 10−3 depending on the strain. The copy number, localization (plasmid or chromosome), and distribution of these elements in the Paracoccus species P. pantotrophus, P. denitrificans, P. methylutens, P. solventivorans, and P. versutus were analyzed. This allowed us to distinguish elements that are common in paracocci (ISPpa2, ISPpa3—both of the IS5 family—and ISPpa5 of IS66 family) as well as strain-specific ones (ISPpa1 of the IS256 family, ISPpa4 of the IS5 family, and Tn3434 and Tn5393 of the Tn3 family), acquired by lateral transfer events. These elements will be of a great value in the design of new genetic tools for paracocci, since only one element (IS1248 of P. denitrificans) has been described so far in this genus.

scholarly journals Characterization of a Class II Defective Transposon Carrying Two Haloacetate Dehalogenase Genes from Delftia acidovorans Plasmid pUO1

2002 ◽  
Vol 68 (5) ◽  
pp. 2307-2315 ◽  
Author(s):  
Masahiro Sota ◽  
Masahiro Endo ◽  
Keiji Nitta ◽  
Haruhiko Kawasaki ◽  
Masataka Tsuda
Keyword(s):  
Transposable Elements ◽  
Class Ii ◽  
Class I ◽  
Inverted Repeats ◽  
High Homology ◽  
Terminal Inverted Repeats ◽  
Delftia Acidovorans

ABSTRACT The two haloacetate dehalogenase genes, dehH1 and dehH2, on the 65-kb plasmid pUO1 from Delftia acidovorans strain B were found to be located on transposable elements. The dehH2 gene was carried on an 8.9-kb class I composite transposon (TnHad1) that was flanked by two directly repeated copies of IS1071, IS1071L and IS1071R. The dehH1 gene was also flanked by IS1071L and a truncated version of IS1071 (IS1071N). TnHad1, dehH1, and IS1071N were located on a 15.6-kb class II transposon (TnHad2) whose terminal inverted repeats and res site showed high homology with those of the Tn21-related transposons. TnHad2 was defective in transposition because of its lacking the transposase and resolvase genes. TnHad2 could transpose when the Tn21-encoded transposase and resolvase were supplied in trans. These results demonstrated that Tn Had2 is a defective Tn21-related transposon carrying another class I catabolic transposon.

STABLE NON-MUTATOR STOCKS OF MAIZE HAVE SEQUENCES HOMOLOGOUS TO THE Mu1 TRANSPOSABLE ELEMENT

Genetics ◽  
1986 ◽  
Vol 114 (3) ◽  
pp. 1007-1021
Author(s):  
Vicki Chandler ◽  
Carol Rivin ◽  
Virginia Walbot
Keyword(s):  
Transposable Element ◽  
Mutation Rate ◽  
Current Evidence ◽  
Mutator Activity ◽  
Restriction Sites ◽  
Initial Characterization ◽  
Element System ◽  
Intact Element ◽  
Internal Probe

ABSTRACT Mutator stocks of maize produce mutants at many loci at rates 20- to 50-fold above spontaneous levels. Current evidence suggests that this high mutation rate is mediated by an active transposable element system, Mu. Members of this transposable element family are found in ~10-60 copies in Mutator stocks. We report here an initial characterization of previously undetected sequences homologous to Mu elements in eight non-Mutator inbred lines and varieties of maize that have a normal low mutation rate. All stocks have ~40 copies of sequences homologous only to the terminal repeat and show weak homology to an internal probe. In addition, several of the stocks contain an intact Mu element. One intact Mu element and two terminal-specific clones have been isolated from one non-Mutator line, B37. The cloned sequences have been used to demonstrate that in genomic DNA the intact element, termed Mu1.4B37, is modified, such that restriction sites in its termini are not accessible to cleavage by the HinfI restriction enzyme. This modification is similar to that observed in Mutator lines that have lost activity. We hypothesize that the DNA modification of the Mu-like element may contribute to the lack of Mutator activity in B37.

scholarly journals Molecular characterization of mariner-like elements in Bruchus pisorum and Bruchus rufimanus (Coleoptera: Bruchidae)

2017 ◽  
Vol 69 (2) ◽  
pp. 353-360 ◽  
Author(s):  
Salma Djebbi ◽  
Amara Ben ◽  
Hanem Makni ◽  
Mohamed Makni ◽  
Maha Mezghani-Khemakhem
Keyword(s):  
Phylogenetic Analysis ◽  
Amino Acid ◽  
Transposable Elements ◽  
Inverted Repeats ◽  
Terminal Inverted Repeats ◽  
Transfer Genes ◽  
Recent Origin ◽  
Bruchus Pisorum ◽  
Respective Host

Mariner-like elements (MLEs) are Class-II transposons that are widely present in diverse organisms and encode a D,D34D transposase motif. MLE sequences from two coleopteran species, Bruchuspisorum and B. rufimanus were obtained using the terminal-inverted repeats (TIRs) of mariner elements belonging to the mauritiana subfamily as primer. The characterized elements were between 1073 and 1302 bp in length and are likely to be inactive, based on the presence of multiple stop codons and/or frameshifts. A single consensus of MLE was detected in B. pisorum and was named Bpmar1. This element exhibited several conserved amino acid blocks as well as the specific D,D(34)D signature. As for B. rufimanus, two MLE consensuses, designated Brmar1 and Brmar2, were isolated, both containing deletions overlapping the internal region of the transposase. Structural and phylogenetic analysis of these sequences suggested a relatively recent origin of Bpmar1 versus a more ancient invasion of Brmar1 and Brmar2 in their respective host genomes. Given that MLEs are potential mediators of insect resistance and have been used as vectors to transfer genes into host genomes, the MLEs characterized in this study will have valuable implications for selecting appropriate transposable elements in transgenesis.

scholarly journals Analysis of a mutator activity necessary for germline transposition and excision of Tc1 transposable elements in Caenorhabditis elegans.

Genetics ◽  
1988 ◽  
Vol 120 (2) ◽  
pp. 397-407
Author(s):  
I Mori ◽  
D G Moerman ◽  
R H Waterston
Keyword(s):  
Caenorhabditis Elegans ◽  
Transposable Elements ◽  
Transposable Element ◽  
Molecular Basis ◽  
Copy Number ◽  
Nematode Caenorhabditis Elegans ◽  
Transposable Element Family ◽  
Genetic Components ◽  
Mutator Activity ◽  
Low Copy Number

Abstract The Tc1 transposable element family of the nematode Caenorhabditis elegans consists primarily of 1.6-kb size elements. This uniformity of size is in contrast to P in Drosophila and Ac/Ds in maize. Germline transposition and excision of Tc1 are detectable in the Bergerac (BO) strain, but not in the commonly used Bristol (N2) strain. A previous study suggested that multiple genetic components are responsible for the germline Tc1 activity of the BO strain. To analyze further this mutator activity, we derived hybrid strains between the BO strain and the N2 strain. One of the hybrid strains exhibits a single locus of mutator activity, designated mut-4, which maps to LGI. Two additional mutators, mut-5 II and mut-6 IV, arose spontaneously in mut-4 harboring strains. This spontaneous appearance of mutator activity at new sites suggests that the mutator itself transposes. The single mutator-harboring strains with low Tc1 copy number generated in this study should be useful in investigations of the molecular basis of mutator activity. As a first step toward this goal, we examined the Tc1 elements in these low copy number strains for elements consistently co-segregating with mutator activity. Three possible candidates were identified: none was larger than 1.6 kb.

scholarly journals Characterization of IS18, an Element Capable of Activating the Silent aac(6′)-Ij Gene ofAcinetobacter sp. 13 Strain BM2716 by Transposition

1998 ◽  
Vol 42 (10) ◽  
pp. 2759-2761 ◽  
Author(s):  
Eric Rudant ◽  
Patrice Courvalin ◽  
Thierry Lambert
Keyword(s):  
Resistance Gene ◽  
Insertion Sequence ◽  
Resistant Mutant ◽  
Open Reading Frame ◽  
Inverted Repeats ◽  
Aminoglycoside Resistance ◽  
Reading Frame ◽  
Terminal Inverted Repeats ◽  
Hybrid Promoter

ABSTRACT Insertion sequence IS18 was detected by analysis of the spontaneous aminoglycoside resistant mutant Acinetobactersp. 13 strain BM2716-1. Insertion of the element upstream from the silent acetyltransferase gene aac(6′)-Ij created a hybrid promoter that putatively accounts for the expression of the aminoglycoside resistance gene. The 1,074-bp IS18 element contained partially matched (20 out of 26 bases) terminal inverted repeats, one of which overlapped the 3′ end of a 935-bp open reading frame potentially encoding a protein related to the transposases of the IS30 family. IS18 was found in 6 out of 29 strains of Acinetobacter sp. 13 but not in 10 strains each of A. baumannii and A. haemolyticus.

scholarly journals An Active Nonautonomous Mobile Element in Sulfolobus islandicus REN1H1

2006 ◽  
Vol 189 (5) ◽  
pp. 2145-2149 ◽  
Author(s):  
Silvia Berkner ◽  
Georg Lipps
Keyword(s):  
Transposable Element ◽  
Mobile Element ◽  
Inverted Repeats ◽  
Terminal Inverted Repeats ◽  
Sulfolobus Islandicus

ABSTRACT In the crenarchaeote Sulfolobus islandicus REN1H1, a mobile element of 321 bp length has been shown to be active. It does not contain terminal inverted repeats and transposes by a replicative mechanism. This newly discovered element has been named SMN1 (for Sulfolobus miniature noninverted repeat transposable element).

scholarly journals The transposable elements of the Drosophila serrata reference panel

2020 ◽  
Author(s):  
Zachary Tiedeman ◽  
Sarah Signor
Keyword(s):  
Transposable Elements ◽  
Transposable Element ◽  
Copy Number ◽  
Genetic Background ◽  
Natural Populations ◽  
Inbred Lines ◽  
Transposable Element Insertion ◽  
Defense Systems ◽  
Drosophila Serrata ◽  
Transposable Element Copy

AbstractTransposable elements are an important element of the complex genomic ecosystem, proving to be both adaptive and deleterious - repressed by the piRNA system and fixed by selection. Transposable element insertion also appears to be bursty – either due to invasion of new transposable elements that are not yet repressed, de-repression due to instability of organismal defense systems, stress, or genetic variation in hosts. Here, we characterize the transposable element landscape in an important model Drosophila, D. serrata, and investigate variation in transposable element copy number between genotypes and in the population at large. We find that a subset of transposable elements are clearly related to elements annotated in D. melanogaster and D. simulans, suggesting they spread between species more recently than other transposable elements. We also find that transposable elements do proliferate in particular genotypes, and that often if an individual is host to a proliferating transposable element, it is host to more than one proliferating transposable element. In addition, if a transposable element is active in a genotype, it is often active in more than one genotype. This suggests that there is an interaction between the host and the transposable element, such as a permissive genetic background and the presence of potentially active transposable element copies. In natural populations an active transposable element and a permissive background would not be held in association as in inbred lines, suggesting the magnitude of the burst would be much lower. Yet many of the inbred lines have actively proliferating transposable elements suggesting this is an important mechanism by which transposable elements maintain themselves in populations.

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