The very large amplifiable element AUD2 from Streptomyces lividans 66 has insertion sequence-like repeats at its ends

Eichenseer, Christa; Altenbuchner, Josef

doi:10.1128/jb.176.22.7107-7112.1994

Cited by 19 publications

(17 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This implicates the involvement of a transposable element in the tandem amplification in the terminal region, an example of which has been reported by Eichenseer et al (1994).…”

Section: Note Added In Proofsupporting

confidence: 73%

“…Two copies of Tn4811 are about 10 kb from the termini. In addition, two insertion sequence-like repeats have been found on both sides of the AUD2 amplifiable element in one terminal region of the S. lividans chromosome (Eichenseer and Altenbuchner, 1994). In the first, transposable element-based, model of instability, the telomeres may play no role or a secondary role.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Instability of artificially circularized chromosomes of Streptomyces lividans

Lin¹,

Chen²

1997

Molecular Microbiology

View full text Add to dashboard Cite

SummaryThe chromosomes of Streptomyces species are linear molecules, containing long terminal inverted repeats and covalently bound terminal proteins. These chromosomes undergo spontaneous deletions of the terminal sequences at high frequencies and become circularized in several cases examined. Artificial circularization of the Streptomyces lividans chromosome was also achieved by targeted recombination in vivo, in which the terminal inverted repeats of the chromosome were connected by a kanamycin resistance gene (aphII ). Under kanamycin selection, the circularized chromosomes harboured tandem amplifications of a 20.2 kb sequence that included the aphII gene flanked by direct repeats and deletions nearby. On release from kanamycin selection, the aphII amplifications and the neighbouring sequences were deleted from the chromosomes, rendering all the cultures kanamycin sensitive. The chloramphenicol resistance gene, which was prone to deletion in wild-type S. lividans, became much more stable in the kanamycin-sensitive derivatives. These results indicate that the telomeres and/or certain terminal sequences may be involved in the structural instability of Streptomyces chromosomes.

show abstract

“…This implicates the involvement of a transposable element in the tandem amplification in the terminal region, an example of which has been reported by Eichenseer et al (1994).…”

Section: Note Added In Proofsupporting

confidence: 73%

Section: Discussionmentioning

confidence: 99%

Instability of artificially circularized chromosomes of Streptomyces lividans

Lin¹,

Chen²

1997

Molecular Microbiology

View full text Add to dashboard Cite

show abstract

“…It was shown previously that the recombination event leading to the amplification of AUD2 occurred within both copies of IS1373 (6). This might be mediated by the RecA protein, as reported for the amplifiable unit AUD1 in S. lividans (22).…”

supporting

confidence: 60%

“…Amplification of AUD1 occurs through a RecA-mediated event of homologous recombination and requires the presence of a DNA-binding protein encoded by the AUD itself (22,23). AUD2 carries mercury resistance genes in S. lividans 1326 and is flanked by two 846-bp large directs repeats (6,17). Both repeats are identical, present 65% identity in nucleic sequence with IS112 of S. albus, and show one unique open reading frame, insA, encoding the putative transposase.…”

mentioning

confidence: 99%

High-frequency transposition of IS1373, the insertion sequence delimiting the amplifiable element AUD2 of Streptomyces lividans

Volff

Altenbuchner

1997

J Bacteriol

Self Cite

View full text Add to dashboard Cite

IS1373 is the putative insertion sequence delimiting the amplifiable unit AUD2 of Streptomyces lividans. Two IS1373-derived thiostrepton-resistant transposons, Tn5492 and Tn5494, transposed into multiple sites of the S. lividans chromosome at frequencies as high as 0.4 and 1%, respectively. Hence, IS1373 is a functional insertion sequence and its unique open reading frame, insA, encodes the transposase.

show abstract

“…1). This region is also found in S. lividans 1326 and is probably involved in regulation (5). No specific structures were found in the 201-bp region between orfX and merB.…”

mentioning

confidence: 91%

Cloning and Sequence Analysis of the Mercury Resistance Operon of Streptomyces sp. Strain CHR28 Reveals a Novel Putative Second Regulatory Gene

et al. 2000

View full text Add to dashboard Cite

A DNA library of pRJ28, a large linear plasmid encoding mercury resistance, was constructed, and the mercury resistance genes were cloned. The 5,921-bp sequence was analyzed and showed a high degree of similarity to the Streptomyces lividans 1326 mercury resistance operon. Genes merR, merT, merP, and orfIV were found in a similar order and in a single transcription unit. merA and merB were found to be transcribed in the opposite direction to genes merR, merT, merP, and orfIV, as in S. lividans 1326. A novel putative regulatory gene, orfX, was found 22 bp downstream of merA. orfX encodes a 137-amino acid protein with a potential helix-turnhelix motif in the N-terminal domain, characteristic of the MerR family of transcriptional regulators. Transcriptional studies showed that orfX is cotranscribed with merA and merB. It is hypothesized that orfX plays a role in the regulation of the mercury resistance operon, probably by binding at the MerR operator site.Mercury resistance is widespread among prokaryotes, and resistance genes are often found on plasmids or transposons (11). The major mechanism of resistance is reductive detoxification of Hg(II) to elemental mercury Hg(0), which is extremely volatile and leaves the cell by diffusing through the cell membrane. The process is mediated intracellularly by a mercuric reductase (MerA). Mercuric ions are transported from outside the cell by a series of transporter proteins. MerP is an extracellular mercuric ion binding protein, and MerT is a membrane-anchored protein responsible for transporting Hg(II) into the cell. All gram-positive and some gram-negative systems are resistant to a broad range of mercuric compounds, including organomercurials like phenylmercuric acetate (PMA) (7). This ability is due to the presence of an organomercurial lyase (MerB) which cleaves the carbon-mercury bonds and releases Hg(II). Narrow-spectrum resistance is observed when the merB gene is missing (17). The systems are regulated by transcriptional regulator MerR. In all cases studied, with the exception of in Streptomyces lividans where MerR is a repressor (14, 16), MerR is an activator/repressor transcriptional regulator. In the presence of Hg(II), MerR binds Hg(II) and activates its own transcription as well as that of the other mer genes. In the absence of Hg(II), MerR binds tightly to an operator and represses the system (7). In a few mercury resistance operons, a second regulator gene, merD, is present and binds weakly to the MerR operator site. MerD has been shown to down-regulate the system (9, 10).We have previously described mercury-resistant Streptomyces strain CHR28, in which mercury resistance genes are encoded by the large linear plasmid pRJ28 (330 kb) (13). CHR28 is an environmental strain isolated from a heavily polluted site in the Baltimore Harbor and might have developed resistance and/or regulation mechanisms adapted to its environment which differ from those of S. lividans 1326. Mercury resistance genes of the laboratory strain S. lividans 1326 have previously been clone...

show abstract

The very large amplifiable element AUD2 from Streptomyces lividans 66 has insertion sequence-like repeats at its ends

Cited by 19 publications

References 20 publications

Instability of artificially circularized chromosomes of Streptomyces lividans

Instability of artificially circularized chromosomes of Streptomyces lividans

High-frequency transposition of IS1373, the insertion sequence delimiting the amplifiable element AUD2 of Streptomyces lividans

Cloning and Sequence Analysis of the Mercury Resistance Operon of Streptomyces sp. Strain CHR28 Reveals a Novel Putative Second Regulatory Gene

Contact Info

Product

Resources

About