Identification and characterization of IS 1138, a transposable element from Mycoplasma pulmonis that belongs to the IS3 family

Bhugra, Bindu; Dybvig, Kevin

doi:10.1111/j.1365-2958.1993.tb01148.x

Cited by 41 publications

(23 citation statements)

References 28 publications

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“…It is not yet determined whether the partially sequenced IS1221 elements identified in this study are functional copies. While there are no data yet supporting vlp gene mobility in M. hyorhinis, IS elements associated with mycoplasma gene rearrangements have been reported (4,14). Moreover, a bacteriophage reported in M. hyorhinis (18) an additional prospective vector for dissemination or exchange of vlp genes.…”

Section: Discussionmentioning

confidence: 99%

Increased structural and combinatorial diversity in an extended family of genes encoding Vlp surface proteins of Mycoplasma hyorhinis

et al. 1995

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Variable lipoproteins (Vlp) constitute the major coat protein of Mycoplasma hyorhinis. They are products of multiple, divergent, single-copy genes organized in a chromosomal cluster. Three genes, vlpA, vlpB, and vlpC, have been previously identified in clonal isolates of M. hyorhinis SK76. Each is linked to a characteristic promoter region containing a homopolymeric tract of adenine residues [poly(A) tract], subject to hypermutation, that transcriptionally controls phase variation of vlp genes and leads to combinatorial surface mosaics of distinct Vlp products. The size of the natural vlp gene repertoire is unknown but may critically determine the degree of structural and combinatorial diversity available in this species. In this study, the vlp repertoire of M. hyorhinis GDL-1 was characterized and shown to contain three additional genes, vlpD, vlpE, and vlpF, clustered with other known vlp genes in the order 5-vlpD-vlpE-vlpF-IS-vlpA-IS-vlpB-vlpC-3, where IS represents copies of the IS1221 element of M. hyorhinis. The 5 boundary of this expanded family was identical to that of the more limited family 5-vlpA-IS-vlpB-vlpC-3 previously described in a clonal isolate of strain SK76. A recombinant construct containing vlpD, vlpE, and vlpF expressed antigenically distinguishable products corresponding to each gene. These genes encode characteristic C-terminal repetitive regions that are subject to size variation by insertion or deletion of intragenic repeats but maintain an extended, charged structure. Each vlp gene also contained characteristic alternative open reading frames, which provide a potential reservoir of coding sequence for Vlp diversity, possibly recruited through insertion and/or deletion mutations. These findings demonstrate a vastly expanded potential for structural diversity and combinatorial display of surface mosaics on this organism and suggest that modulation of the vlp repertoire, possibly in conjunction with mobile elements, may determine the capacity for surface variation in natural populations and laboratory strains of this mycoplasma species.The variable lipoprotein (Vlp) system of Mycoplasma hyorhinis provides a mutational strategy for adaptive surface variation that generates extreme population diversity in the major coat proteins expressed on this wall-less procaryote (27,28,38,40). The complexity of this system and its role as a prototype for analogous emerging systems in other mycoplasma species warrants a detailed characterization of the genetic and structural attributes contributing to its adaptive capabilities. Vlps are procaryotic lipoproteins processed by cleavage of a conserved prolipoprotein sequence (11) and expressed as abundant surface proteins anchored on the single mycoplasma membrane by a lipid moiety on an N-terminal Cys residue. Molecular genetic analysis has shown that alternative Vlps share distinctive structural features despite divergence throughout their surface-exposed protein sequence. Structural details of known Vlps (VlpA, VlpB, and VlpC) have been defined at the g...

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Section: Discussionmentioning

confidence: 99%

Increased structural and combinatorial diversity in an extended family of genes encoding Vlp surface proteins of Mycoplasma hyorhinis

et al. 1995

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“…The PMUs contain tra5 ISs, which belong to the IS150 group and the IS3 family (53,58 (58,66). All of these elements belong to the IS150 subgroup, and it has been demonstrated that some of these elements undergo autonomous transposition (16). PMU1 of AY-WB is the longest, appears to be the most complete, and has several striking features characteristic of composite transposons (Fig.…”

Section: Discussionmentioning

confidence: 99%

Living with Genome Instability: the Adaptation of Phytoplasmas to Diverse Environments of Their Insect and Plant Hosts

Bai

Zhang

Ewing³

et al. 2006

J Bacteriol

350

447

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Phytoplasmas ("CandidatusPhytoplasmaThe phylogenetic tree of mollicutes is composed of two major clades that diverged early in evolution (51). One clade contains the orders Acholeplasmatales and Anaeroplasmatales (AAA clade mollicutes), and the other clade contains the orders Mycoplasmatales and Entomoplasmatales (SEM clade mollicutes) (9). Phytoplasmas, formerly known as mycoplasma-like organisms of plants, form a monophyletic group in the order Acholeplasmatales (51) and were recently assigned to a novel genus, "Candidatus Phytoplasma" (41). Approximately 20 phytoplasma phylogenetic groups have been proposed based on 16S rRNA gene sequences, and new branches are continuously being discovered (69,85). Members of the order Acholeplasmatales are distinct from other mollicutes in several ways. For instance, whereas most mollicutes use UGA as a tryptophan codon instead of a stop codon, a feature they share with mitochondria, the acholeplasmas and phytoplasmas retained UGA as a stop codon (80).

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“…The family is quite homogeneous in spite of its wide distribution in bacteria exhibiting a large range of G+C contents and of the presence of members in hosts such as Mycoplasma with a nonuniversal genetic code (e.g., IS1138) or in bacteria that use stop codon read-through by insertion of the unusual amino acid selenocysteine (e.g., ISDvu3 from Desulfovibrio vulgaris). In the case of both copies of IS1138, which participates in highfrequency rearrangements of the Mycoplasma pulmonis chromosome, the Tpase orf carries 11 UGA codons, which are decoded as tryptophan (144).…”

Section: Is3 and Is481 Families Is3 (I) Generalmentioning

confidence: 99%

Everyman's Guide to Bacterial Insertion Sequences

et al. 2015

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The number and diversity of known prokaryotic insertion sequences (IS) have increased enormously since their discovery in the late 1960s. At present the sequences of more than 4000 different IS have been deposited in the specialized ISfinder database. Over time it has become increasingly apparent that they are important actors in the evolution of their host genomes and are involved in sequestering, transmitting, mutating and activating genes, and in the rearrangement of both plasmids and chromosomes. This review presents an overview of our current understanding of these transposable elements (TE), their organization and their transposition mechanism as well as their distribution and genomic impact. In spite of their diversity, they share only a very limited number of transposition mechanisms which we outline here. Prokaryotic IS are but one example of a variety of diverse TE which are being revealed due to the advent of extensive genome sequencing projects. A major conclusion from sequence comparisons of various TE is that frontiers between the different types are becoming less clear. We detail these receding frontiers between different IS-related TE. Several, more specialized chapters in this volume include additional detailed information concerning a number of these.In a second section of the review, we provide a detailed description of the expanding variety of IS, which we have divided into families for convenience. Our perception of these families continues to evolve and families emerge regularly as more IS are identified. This section is designed as an aid and a source of information for consultation by interested specialist readers.

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Identification and characterization of IS 1138, a transposable element from Mycoplasma pulmonis that belongs to the IS3 family

Cited by 41 publications

References 28 publications

Increased structural and combinatorial diversity in an extended family of genes encoding Vlp surface proteins of Mycoplasma hyorhinis

Increased structural and combinatorial diversity in an extended family of genes encoding Vlp surface proteins of Mycoplasma hyorhinis

Living with Genome Instability: the Adaptation of Phytoplasmas to Diverse Environments of Their Insect and Plant Hosts

Everyman's Guide to Bacterial Insertion Sequences

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