IS431, a staphylococcal insertion sequence-like element related to IS26 from Proteus vulgaris

Barberis-Maino, Luisella; Berger‐Bächi, Brigitte; Weber, Hans; Beck, Wolfgang D.; Kayser, Fritz H.

doi:10.1016/0378-1119(87)90271-x

Cited by 101 publications

(53 citation statements)

References 13 publications

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“…The protein specified by the transposase gene from the iso-ISS1 element has 86.2 to 98.2% identity with ISS1 from L. lactis (6,15,26,27). It also shares high identity with insertion elements from other bacterial species: IS257 and IS431 from Staphylococcus aureus (57.5% [2,28]); IS26 from Proteus vulgaris (43.6% [23]); IS6100 from Mycobacterium fortuitum (42.5% [22]); IS240 from Bacillus thuringiensis (41.7% [8]); and IS15 from Salmonella typhimurium (40.4% [24]). All these insertion elements belong to the IS6 family (22).…”

Section: Resultsmentioning

confidence: 99%

Characterization of the lactococcal abiD1 gene coding for phage abortive infection

et al. 1995

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Lactococcal phage abortive infection (AbiD1) determined by plasmid pIL105 is active on both prolate-and small-isometric-head phages of the C6A and 936 phage groups, respectively, which are considered two different species. The Abi phenotype was found to be encoded by a single gene, designated abiD1. The abiD1-encoded protein (351 amino acids) does not show homology with any known protein and has a deduced isoelectric point of 10. It also possesses two helix-turn-helix structures and an unusually high content of asparagine, isoleucine, and lysine. A consensual promoter with a TGy extension to the ؊10 box was mapped 76 bp upstream of the start codon. Transcription initiated at this strong promoter stops at a terminator located 48 bp downstream from the promoter. The termination process is very efficient, and transcripts corresponding to the abiD1 gene were not visible in our experimental conditions with or without phage infection. Expression of abiD1 under the control of a T7 promoter induced a lag phase in Lactococcus lactis cell growth, suggesting that overproduction of AbiD1 could be toxic for the cells. AbiD1 protein was visualized in Escherichia coli by using a tightly controlled expression system.Lactococci are widely used for the manufacture of dairy products, where they are challenged with high concentrations of a variety of phages. Eleven different phage species have been defined according to DNA homology (18). These highly selective environmental conditions are most probably responsible for the selection of strains with a high degree of phage resistance. Some of these strains were shown to have accumulated several types of defense mechanisms, including adsorption interference, restriction and modification, and abortive infection (4,10,12,19). Therefore, lactococci represent a good model with which to study the coevolution of bacteria and phages and to identify phage defense mechanisms. One of these, abortive infection, abruptly interrupts phage development, resulting in the release of few or no progeny particles and cell death. This phenotype resembles that conferred by F on Escherichia coli infected by phage T7 (29). Three lactococcal genes coding for an Abi phenotype have been cloned and sequenced (6,7,10,16). The proteins specified by these genes, designated abiA, abiB, and abiC, have no homology with protein sequences in the data banks and are not cross-homologous. There is presently no hypothesis concerning their mode of action.In this work, we established that the Abi phenotype conferred by pIL105, previously shown to be active on lactococcal phages of two different species (12), is determined by a single gene, designated abiD1. Transcription initiated at a strong consensus promoter stops at a terminator located upstream of the gene. Transcripts corresponding to abiD1 were not detectable under our experimental conditions, indicating that the gene is expressed at a low level before or after phage infection. This may be due to some toxicity of the AbiD1 protein, suggested by a lag phase in the growth...

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Section: Resultsmentioning

confidence: 99%

Characterization of the lactococcal abiD1 gene coding for phage abortive infection

et al. 1995

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“…Homologous sequences in directly repeated orientation have also been found in six additional locations on pGO1, including one copy at each end of the gene encoding resistance to trimethoprim (12). These IS-like elements have also been identified at either end of the genes encoding mercury resistance on staphylococcal penicillinase plasmids and at one end of the staphylococcal chromosomal gene(s) responsible for methicillin resistance (5). The association of these IS-like elements with multiple resistance determinants in both plasmid and chromosomal loci implies an involvement of these elements in the movement of genes in staphylococci, including those for conjugative transfer.…”

Section: Discussionmentioning

confidence: 99%

Identification and cloning of the conjugative transfer region of Staphylococcus aureus plasmid pGO1

Thomas

Archer

1989

J Bacteriol

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The conjugative transfer (tra) genes of a 52-kilobase (kb) staphylococcal plasmid, pGO1, were localized by deletion analysis and transposon insertional inactivation. All transfer-defective (Tra-) deletions and TnS51 or Tn917 transposon insertions occurred within a 14.5-kb BglII fragment. Deletions and insertions outside this fragment all left the plasmid transfer proficient (Tra'). The tra region was found to be flanked by directly repeated DNA sequences, approximately 900 base pairs in length, at either end. Clones containing the 14.5-kb BgllI fragment (pGO200) and subclones from this fragment were constructed in Escherichia coli on shuttle plasmids and introduced into Staphylococcus aureus protoplasts. Protoplasts could not be transformed with pGO200E (pGO200 on the staphylococcal replicon, pE194) or subclones containing DNA at one end of the tra fragment unless pGO1 or specific cloned tra DNA fragments were present in the recipient cell. However, once stabilized by sequences present on a second replicon, each tra fragment could be successfully introduced alone into other plasmid-free S. aureus recipients by conjugative mobilization or transduction. In this manner, two clones containing overlapping fragments comprising the entire 14.5-kb BglII fragment were shown to complement each other. The low-frequency transfer resulted in transconjugants containing one clone intact, deletions of that clone, and recombinants of the two clones. The resulting recombinant plasmid (pGO220), which regenerated the tra region intact on a single replicon, transferred at frequencies comparable to those of pGO1. Thus, all the genes necessary and sufficient for conjugative transfer of pGO1 are contained within a 14.5-kb region of DNA.Large, 40-to 60-kilobase (kb) conjugative plasmids have been found in both Staphylococcus aureus and S. epidermidis (3,11,24). Conjugative transfer of these plasmids has the following characteristics: transfer occurs at a low frequency The 52-kb conjugative plasmid pGO1, originally resident in a clinical S. aureus isolate at the Medical College of Virginia Hospital, has all of the transfer characteristics summarized above, encodes Gmr, Tpr, and Qamr, and has both restriction fragment similarity and DNA hybridization homology to conjugative plasmids isolated from our own hospital (2) as well as to plasmids from the University of * Corresponding author.Michigan (pAM899-1) and Creighton University (pCRG1600) (G. Archer, unpublished observations). Thus, this plasmid serves as a model for the study of conjugative staphylococcal plasmid tra genes. As a first step toward a detailed genetic and functional analysis of the tra region of these plasmids, in this report we describe a determination of the physical and functional boundary of the genes encoding transfer functions on pGO1. In addition, tra insertion and deletion mutants and subclones of the tra region on S. aureus-Escherichia coli shuttle vectors were constructed to aid in future studies of the molecular basis for the conjugative transfer of antimicrob...

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“…In contrast, plasmid pCER102, which contained the 3.2-kb EcoRI fragment from COH-31 expressed two proteins of 24 and 22 kDa (Fig. 6, lane D) (1,2,10,12).…”

Section: Resultsmentioning

confidence: 98%

IS861, a group B streptococcal insertion sequence related to IS150 and IS3 of Escherichia coli

1989

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A 1,442-base-pair (bp) insertion sequence (IS861) was identified in the type Ill group B streptococcal (GBS) strain COH-1. It is flanked by 26-bp imperfect inverted repeats and contains two open reading frames, 1 and 2, encoding 141-and 277-amino-acid proteins, respectively. A 3-bp target sequence, ACA, is duplicated and flanks each inverted repeat. IS861 shares greater than 30% homology with IS3 and IS150 of Escherichia coli, primarily in the region of their putative transposases. Northern (RNA) analysis revealed that RNA is actively transcribed in vivo by IS861 and 17-and 36-kilodalton proteins were synthesized in E. coli maxicell assays. Multiple copies of IS861 were observed throughout the chromosome of COH-1, and one of the copies is located near genes involved in GBS capsule synthesis. IS861 is the first insertion sequence identified in GBS. Its role in GBS and the significance of its relationship to the phylogenetically similar insertion sequences typified by IS150 and IS3 of E. coli are unknown.

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IS431, a staphylococcal insertion sequence-like element related to IS26 from Proteus vulgaris

Cited by 101 publications

References 13 publications

Characterization of the lactococcal abiD1 gene coding for phage abortive infection

Characterization of the lactococcal abiD1 gene coding for phage abortive infection

Identification and cloning of the conjugative transfer region of Staphylococcus aureus plasmid pGO1

IS861, a group B streptococcal insertion sequence related to IS150 and IS3 of Escherichia coli

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