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At least 523 records · Page 29Linked to original sources
PubMed1988

Transposition of the Streptococcus lactis ssp. lactis Z270 lactose plasmid to pVA797: demonstration of an insertion sequence and its relationship to an inverted repeat sequence isolated by self-annealing.

The lactose plasmid pUCL22 of the single plasmid strain Streptococcus lactis ssp. lactis Z270 was demonstrated to fuse with the heterologous conjugative plasmid pVA797. The fusion of pUCL22 with pVA797 occurred by recombination between a specific sequence of pUCL22 and different sites of pVA797. The cointegrates of pUCL22::pVA797 were unstable: in the absence of lactose selection, they segregated plasmids that corresponded to pVA797 enlarged by one sequence of 1.2 kb, common to all derivative plasmids. This resolution sequence (RS) was shown to originate in the 9.7 kb BstEII restriction fragment of pUCL22 and to duplicate during replicon fusion. In addition, after nuclease S1 treatment of pUCL22 DNA, a self-annealing sequence was isolated; the two copies of this inverted repeat (IR) sequence were located on the 18 kb BamHI segment of the plasmid. This latter sequence was distinct from the RS with which it hybridized weakly. The RS was responsible for the transposition of the entire lactose plasmid; the role of the IR remains to be elucidated.

Conjugation, Genetic↗
PubMed1988

Insertion sequence IS2 in the cyanobacterium Chlorogloeopsis fritschii.

A cloned DNA fragment, previously demonstrated to encode ribulose bisphosphate carboxylase/oxygenase (RuBisCO) of Chlorogloeopsis fritschii strain CCAP1411/1b, is shown also to include the entire transposable element, IS2, normally a resident in the Escherichia coli genome. Southern-blot hybridisation experiments confirm the presence of IS2 in the C. fritschii genome. This finding adds a new and unrelated species to the known host range of this element and provides evidence of genetic transfer between the Gram-negative E. coli and cyanobacteria. This may also have significance in relation to the nucleotide sequence rearrangements known to occur adjacent to RuBisCO and nif genes in other nitrogen-fixing cyanobacteria.

Base Sequence↗
PubMed1989

Saturation mutagenesis of the inside end of insertion sequence IS50.

A 19-bp segment at the inside (I) end of IS50 (Tn5) is needed for efficient transposition. The importance of each position was assayed by making at least one base substitution at each position by either chemical-or oligodeoxyribonucleotide-directed mutagenesis. Mutant I ends were paired with a wild-type (wt) segment from the outside (O) end of IS50 and the transposase (tnp) gene was placed either between the ends or 1200 bp from the O end. The frequency of transposition of the resultant elements to bacteriophage lambda was measured. At least one substitution at each of the 19 I-end positions decreased transposition activity to less than 25% of wt, and most substitutions (25 of 28) decreased it to less than 5% of wt from one or both donor plasmids. These results show that each position in the I end is important during transposition.

Base Sequence↗
PubMed1994

Characterization of IS1203, an insertion sequence in Escherichia coli O111:H-.

The complete nucleotide (nt) sequence of IS1203 from Escherichia coli O111:H- strain PH has been determined. IS1203 is 1312-nt long, with imperfect 26-bp terminal inverted repeats. The two major ORFs in IS1203 encode polypeptides of 12.7 and 33.7 kDa, the latter being the putative transposase. IS1203 is closely related to IS629 of Shigella sonnei and IS3411 of E. coli. At least twelve copies of IS1203 were found in the genome of E. coli O111:H- strain PH.

Amino Acid Sequence↗
PubMed1982

DNA insertion sequences near the insulin gene affect glucose regulation.

There is restriction-fragment length polymorphism in the 5'-flanking region of the insulin gene on the short arm of chromosome 11 in man. The polymorphic DNA sequences in 53 members of a large family were analysed by means of the restriction endonuclease BglI. In this family, the BglI restriction fragments were found in four sizes--2.8 kilobases (kb), 2.9 kb, 4.6 kb, and 4.8 kb. They segregated as alleles. The two larger BglI restriction fragments (U alleles) were associated with high haemoglobin Alc levels in both blood-related and unrelated non-diabetic members of the family.

Adolescent↗
PubMed2002

A survey of metazoan selenocysteine insertion sequences.

The computational detection of novel selenoproteins in genomic sequences is usually achieved through identification of SECIS, a conserved secondary structure element found in the 3' UTR of animal selenoprotein mRNAs. Previous studies have used "descriptors" specifying the number of base pairs and the conserved nucleotides in SECIS to identify this element. A major drawback of the "descriptor" approach is that the number of detections in current genomic or transcript databases largely exceeds the number of true selenoproteins. In this study, we use instead the ERPIN program to detect SECIS elements. ERPIN is based on a lod-score profile algorithm that uses a training-set of aligned RNA sequences as input. From an initial alignment of 44 animal SECIS sequences, we performed a series of iterative searches in which the training set was progressively enriched up to 117 confirmed SECIS elements, from a large collection of metazoan species. About 200 high-scoring candidates were also detected. We show that ERPIN scores for these candidates can be converted into expect values, thus enabling their statistical evaluation. The most interesting SECIS candidates are presented.

Animals↗
PubMed1997

Conserved features of selenocysteine insertion sequence (SECIS) elements in selenoprotein W cDNAs from five species.

SECIS elements form stem-loop structures in the 3' untranslated regions (UTR) of eukaryotic mRNAs that encode selenoproteins. These elements direct incorporation of selenocysteine at UGA codons, provided the SECIS element lies a sufficient distance from the UGA. The cDNAs encoding skeletal muscle selenoprotein W from human, rhesus monkey, sheep, rat, and mouse contained highly similar SECIS elements that retained important features common to all known SECIS elements. Comparative analysis of these SECIS elements showed that in some regions both predicted secondary structure and nucleotide sequences were conserved, in other areas secondary structure was maintained using different primary sequence, and in still other portions, base pairing was not conserved. The rodent and sheep selenoprotein W mRNAs used UGA as a stop codon and as a selenocysteine codon. Thus, UGA specified both selenocysteine incorporation and termination in a single mRNA. The selenoprotein W SECIS elements contained an additional highly conserved base-paired stem that may prevent inappropriate selenocysteine incorporation at the UGA stop codons.

Amino Acid Sequence↗
PubMed1994

Insertion sequence IS200 fingerprinting of Salmonella typhi: an assessment of epidemiological applicability.

When Pst I-generated digests of genomic DNA from each of the type strains of 49 of the Vi phage types of Salmonella typhi were probed with a PCR-amplified IS200 gene probe, all strains were found to possess at least 11 IS200 elements carried on fragments in the range 24.2-1.2 kb. Fourteen fingerprints were identified but two patterns designated IS200Sty1 and IS200Sty2 predominated. In one strain, a plasmid-mediated IS200 element was identified. When IS200 fingerprinting was applied to epidemiologically-unrelated strains of S. typhi isolated in Ecuador, 3 patterns were identified in 10 strains belonging to 9 different phage types. It is concluded that Vi phage typing remains the method of choice for the primary differentiation of S. typhi but that IS200 fingerprinting may be of limited use in laboratories which do not have access to phage typing.

Bacteriophage Typing↗
PubMed1999

Nuclear insertion sequences of mitochondrial DNA predominate in hair but not in blood of elephants.

Hair has become a widely used source of DNA in population genetics, forensics, and conservation biology. Here were report that PCR primers that amplify a segment of the mitochondrial control region from blood DNA amplify primarily integrated nuclear copies of mitochondrial DNA from hair DNA. Thus, in some species, and under some circumstances, DNA from hair may yield unreliable results.

Animals↗