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Results for “insertion, inversion”

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PubMed1998

Interstitial deletion del(3)(p12p21) in a malformed child subsequent to paternal paracentric insertion (or intraarm shift) 46,XY, ins(3)(p24.1p12.1p21.31).

We report on a malformed stillborn with deletion 3p subsequent to direct paracentric insertion (intraarm shift) in the normal father which had been first mistaken for paracentric inversion. The corrected diagnosis was supported by FISH of mapped markers on metaphase chromosomes. In addition we looked for recombinants in sperm. This observation reminds similar cases that had been considered exceptions to the expected meiotic recombination of paracentric inversions and points to a cytogenetic pitfall. Published deletions and paracentric inversions in 3p are briefly quoted.

Abnormalities, Multiple↗

PubMed2000

Changes in the N- and C-terminal sequences of the murine R7 Gag-tMos protein affect brain lesion induction.

Our preliminary studies suggested that the novel gag-truncated mos (tmos) open reading frame (ORF) of R7, a spontaneous deletion mutant of Moloney murine sarcoma virus 124 (MoMuSV124), may be responsible for R7's unique ability to induce brain lesions in all R7-injected mice. However, when we replaced the gag-tmos ORF with either the MoMuSV124 or the homologous myeloproliferative sarcoma virus env-mos gene, we found that both recombinant viruses also induced brain lesions in all injected mice. Although these studies suggested that the critical determinants for brain lesion induction may reside in the tmos sequence common to all three viruses, they did not demonstrate if the N-terminus of Mos was dispensable for this activity. By inserting the FLAG sequence at the 3' end of the R7 gag-tmos ORF, we demonstrated that R7 does synthesize a Gag-tMos fusion protein. Using R7 gag deletion mutants with and without the FLAG sequence, we further demonstrated that (i) deletion of the entire gag sequence abolished R7's transforming activity; (ii) the ability of the virus to transform cultured NIH/3T3 cells was significantly reduced only when most of gag was deleted; (iii) the ability of the virus to induce brain lesions was inversely proportional to the extent of its gag deletions; and (iv) the insertion of FLAG at the Mos C-terminus did not reduce the in vitro transforming activity of the FLAG-tagged viruses but did reduce their ability to induce brain lesions. Thus, we have demonstrated that altering the N- or C-terminus of the R7 Gag-tMos fusion protein can affect disease manifestation.

3T3 Cells↗

PubMed1988

Escherichia coli host factor for site-specific DNA inversion: cloning and characterization of the fis gene.

The Escherichia coli (Es. coli) protein Fis (factor for inversion stimulation) stimulates site-specific DNA inversion of the G segment in phage Mu by binding to a recombinational enhancer. By using synthetic oligonucleotides deduced from the amino-terminal amino acid sequence, we have cloned the gene (termed fis) encoding this specific DNA-binding protein. The DNA sequence shows that the Fis protein is basic and contains 98 amino acids. A helix-turn-helix sequence motif characteristic of many DNA-binding proteins is located at the carboxyl-terminal end of the protein. By marker exchange, we have constructed an insertion mutation of fis. Fis is nonessential for Es. coli growth; however, inversion of the G segment of a Mu prophage was not detected in the fis mutant. The fis gene is located between 71 and 72 min on the Es. coli genetic map.

Amino Acid Sequence↗

PubMed2004

Silencing of a gene adjacent to the breakpoint of a widespread Drosophila inversion by a transposon-induced antisense RNA.

Adaptive changes in nature occur by a variety of mechanisms, and Drosophila chromosomal inversions was one of the first studied examples. However, the precise genetic causes of the adaptive value of inversions remain uncertain. Here we investigate the impact of the widespread inversion 2j of Drosophila buzzatii on the expression of the CG13617 gene, whose coding region is located only 12 bp away from the inversion proximal breakpoint. This gene is transcribed into a 2.3-kb mRNA present in all D. buzzatii developmental stages. More importantly, the expression level of CG13617 is reduced 5-fold in embryos of lines homozygous for the 2j inversion compared with lines without the inversion. An antisense RNA that originates in the Foldback-like transposon Kepler inserted at the breakpoint junction in all of the 2j lines and that forms duplexes with the CG13617 mRNA in 2j embryos is most likely responsible for the near silencing of the gene. Few examples of RNA interference caused by transposable elements (TEs) have been previously described, but this mechanism might be prevalent in many organisms and illustrates the potential of TEs as a major source of genetic variation. In addition, because chromosomal rearrangements are usually induced by TEs, position effects might be more common than previously recognized and contribute significantly to the evolutionary success of inversions.

Animals↗

PubMed2003

Chased PCR: A modified inverse PCR technique to characterize flanking regions of AT-rich DNA fragments.

The chased polymerase chain reaction (PCR) technique described here is a convenient method enabling the characterization of flanking regions of a known A/T-rich DNA fragment in two different successive steps. The first step includes a modified inverse PCR with inverted tail-to-tail primers, each with 35 overhanging nucleotides for the insertion into a carrier plasmid. The second step consists of a technique similar to a site-directed mutagenesis. The chased PCR technique is simple, quick, versatile and efficient; it improves the inverse PCR technique and may be applied to any ligation-linker method. Consequently, the techniques for PCR-based gene isolation are more suitable for the isolation of missing sequences of A/T-rich or complex DNA.

Animals↗

PubMed2002

Molecular cytogenetic analysis of 10;11 rearrangements in acute myeloid leukemia.

MLLT10 (previously called AF10) is a moderately common MLL fusion partner predominantly occurring in acute monoblastic leukemia (AML-M5). 10;11 rearrangements require at least three breaks in order to generate an in-frame MLL-MLLT10 fusion as a result of the opposite orientations of both genes on the respective chromosome arms. In this study, we describe a detailed molecular cytogenetic analysis of MLL-MLLT10 positive 10;11 rearrangements in two patients. We observed an as yet unreported chromosomal mechanism with at least four breakpoints, leading to MLL-MLLT10 gene fusion in a 24-year-old male. An inversion of 11q13-q23 with a breakpoint in the MLL gene was followed by an additional break 3' of MLL prior to insertion of the 11q segment into MLLT10. In a second patient, a 37-year-old male with AML-M5b, molecular cytogenetic analysis of an apparent 10;11 reciprocal translocation showed an intrachromosomal inversion of 3'MLLT10followed by a reciprocal translocation between 10p12 and 11q23. Review of the literature showed that all cases were the result of an inversion of either 10p or 11q followed by translocation 10p;11q or insertion of the inverted segment into MLLT10 or MLL.

Acute Disease↗

PubMed2002

Performance of twin central venous catheters: influence of the inversion of inlet and outlet on recirculation.

BACKGROUND: The use of a central venous catheter as a permanent vascular access is constantly growing. The recirculation rate in this type of vascular access varies depending on the site of insertion, the length of the catheter, the blood flow and the time elapsed since catheter insertion. When the in/out flow of the lumens of the catheter is reduced, it is sometimes necessary to inverse the arterial and venous lines of the catheter at the beginning or in the course of the dialysis session. The impact of such a practice on the recirculation rate has only been assessed by the low flow urea dilution method. METHODS: The blood recirculation rate was measured using the ultrasound dilution velocity method (Transonic system, Ithaca, N.Y.) in 14 patients (aged 64 +/- 15 years), with a right internal jugular (n = 9) or right subclavian (n = 5) central catheter (Twincath, Medcomp), used over a mean period of 16.3 (range 1-42) months. No clinical dysfunction of the catheter was apparently noted. The distance between the vein and the artery end of the catheter was 3.9 +/- 2.8 cm, measured on chest radiography. The recirculation rate was measured over a single dialysis session at increasing blood flows in the normal and inversed position of the catheter. RESULTS: The difference between the prescribed and effective blood flow was significant with an effective blood flow of 180 +/- 16 ml/min for 200 ml/min, 264 +/- 27 ml/min for 300 ml/min and 329 +/- 16 ml/min for 400 ml/min prescribed blood flow. There was no relationship between the recirculation rate and blood flow whatever the position of the lines on the catheter. There was also no relationship between the recirculation rate and the distance between the catheter ends. However, reversing the catheter ends significantly increased the recirculation rates from 2.9 +/- 5 to 12 +/- 9% whatever the blood flow. CONCLUSION: The use of central catheters in an inversed position can result in a higher recirculation rate. Reversing the lines of the central catheters may lead to less effective hemodialysis and it seems particularly important for the nursing staff to be aware of this phenomenon. Thus, measurement of the effective blood flow and recirculation by ultrasound velocity should be included in quality monitoring and maintenance.

Aged↗

PubMed1997

Genomic evolution of the distal Mhc class I region on mouse Chr 17.

A 5-Mb YAC contig, partly supplemented with BAC contigs, was created from the distal Mhc class I region on mouse Chr 17. The gene order of Znf173-Tctex5-Mog-D17Tu42-D17Leh 89 is conserved between mouse and human but not the physical distance, supporting the independent expansion of Mhc class I genes in the so-called accordion model of Mhc evolution. The distal H2-M region includes the breakpoint of conserved synteny between mouse and human as well as the In(17)4 t-inversion. The H2-M region is rich in L1 repeats, implying that the insertion of L1 repeats may be associated with the evolutionary flexibility to break a chromosome.

Animals↗

PubMed1993

A common proviral integration region, fit-1, in T-cell tumors induced by myc-containing feline leukemia viruses.

Feline leukemia viruses carrying transduced v-myc genes (myc-FeLV) induce tumors of clonal origin, suggesting that activated myc alone is not sufficient for tumorigenesis. To investigate the hypothesis that insertional mutagenesis plays a role by activating genes which collaborate with v-myc, we looked for evidence of common proviral integration sites in these tumors. By inverse polymerase chain reaction we identified a 6-kb domain, designated fit-1, in which FeLV proviruses were inserted in four of nine (44%) T-cell tumors induced by myc-FeLV. The fit-1 locus was mapped to feline chromosome B2 and appears to be distinct from known oncogenes located on this chromosome. Fit-1 represents a novel common proviral integration region which may harbor a cellular gene which acts in concert with the myc gene in T-cell tumorigenesis.

Animals↗

PubMed1999

[Isolation and genetic analysis of double hyperunstable systems in Drosophila melanogaster].

Hyperunstable mutations were described previously at the yellow locus of Drosophila melanogaster. These mutations are related to the insertion of the complex sequence containing two deleted copies of the P element at the termini and central unique regions from different sites of the X chromosome. In this work, double hyperunstable mutations at loci yellow and scute were obtained. These events were shown to occur from the inversion induced by the P elements located at the loci yellow and scute.

Alleles↗

PubMed1999

Intramolecular transposition of insertion sequence IS91 results in second-site simple insertions.

A series of plasmids carrying an IRL-kan-IRR transposable cassette, in which IRL and IRR are the left- and right-terminal sequences of IS91, have been constructed. These cassettes could be complemented for transposition with similar efficiency when IS91 transposase was provided either in cis or in trans. A total of 87% of IS91 transposition products were simple insertions of the element, while the remaining 13% were plasmid fusions and co-integrates. When transposase expression was induced from an upstream lac promoter, transposition frequency increased approximately 100-fold. An open reading frame (ORF) present upstream of the transposase gene, ORF121, could be involved in target selection, as mutations affecting this ORF were altered in their insertion specificity. Intramolecular rearrangements were analysed by looking at transposition events disrupting a chloramphenicol resistance gene (cat ) located outside the transposable cassette. Plasmid instability resulting from insertion of an extra copy of IRL-kan-IRR within the cat gene was observed; transposition products contained a second copy of the cassette inserted either as a direct or as an inverted repeat. No deletion or inversion of the intervening DNA was observed. These results could be explained as a consequence of intramolecular transposition of IS91 according to a model of rolling-circle transposition.

Chloramphenicol Resistance↗

PubMed1999

[Isolating the ends of yeast artificial chromosome by inverse polymerase chain reaction].

OBJECTIVE: To establish a highly efficient method for isolating yeast artificial chromosome(YAC) ends. METHODS: Based on the sequence of TAC vector, the frequent cutting enzymes were used to cleave within the vector and the genomic insert to generate relatively small fragments,which were ligated and subsequently amplified using vector primers that are in inverse orientation. The PCR products were purified and sequenced. RESULTS 8 YAC termini were isolated from YAC 776E2,964C5,11D8 and 8D1. CONCLUSION: The results suggest that inverse PCR be an efficient method for isolating YAC termini.

Chromosomes, Artificial, Yeast↗

PubMed2003

Football boot insoles and sensitivity to extent of ankle inversion movement.

BACKGROUND: The capacity of the plantar sole of the foot to convey information about foot position is reduced by conventional smooth boot insoles, compared with barefoot surface contact. OBJECTIVE: To test the hypothesis that movement discrimination may be restored by inserting textured replacement insoles, achieved by changing footwear conditions and measuring the accuracy of judgments of the extent of ankle inversion movement. METHODS: An automated testing device, the ankle movement extent discrimination apparatus (AMEDA), developed to assess active ankle function in weight bearing without a balance demand, was used to test the effects of sole inserts in soccer boots. Seventeen elite soccer players, the members of the 2000 Australian Women's soccer squad (34 ankles), took part in the study. Subjects were randomly allocated to start testing in: bare feet, their own football boots, own football boot and replacement insole, and on the left or right side. Subjects underwent six 50 trial blocks, in which they completed all footwear conditions. The sole inserts were cut to size for each foot from textured rubber "finger profile" sheeting. RESULTS: Movement discrimination scores were significantly worse when subjects wore their football boots and socks, compared with barefoot data collected at the same time. The substitution of textured insoles for conventional smooth insoles in the football boots was found to restore movement discrimination to barefoot levels. CONCLUSIONS: The lower active movement discrimination scores of athletes when wearing football boots with smooth insoles suggest that the insole is one aspect of football boot and sport shoe design that could be modified to provide the sensory feedback needed for accurate foot positioning.

Adult↗

PubMed1997

ES cell cycle rates affect gene targeting frequencies.

We have investigated the gene targeting frequency at the hprt locus in a range of embryonic stem cell lines selected for variations in cell cycle parameters. Our results show that targeting frequency varies with cell line by as much as 12-fold between nonisogenic lines and 3-fold between isogenic lines and that a nonisogenic line can support homologous recombination events by up to 21-fold more frequently than an isogenic line. This variation is consistent with both insertion and replacement vectors. These results can be explained by an inverse linear correlation of targeting frequencies with cell doubling times. Additionally, by reducing serum concentration in the culture medium the mean cell doubling time for R1 ES cells can be increased from 11.4 to 15.7 h, with a subsequent 15-fold decrease in gene targeting frequency. This change fits the correlation found for the different nonisogenic cell lines. Our observations have important implications when performing gene targeting experiments and explain some of the variation noted between experiments.

Animals↗

PubMed2000

Identification of Actinobacillus pleuropneumoniae virulence genes using signature-tagged mutagenesis in a swine infection model.

Actinobacillus pleuropneumoniae is a significant respiratory pathogen of swine causing a severe and often fatal fibrinous hemorrhagic bronchopneumonia with significant economic losses resulting from chronic as well as acute infections. This study describes the application of a signature-tagged mutagenesis (STM) system to identify in vivo critical genes of A. pleuropneumoniae. Twenty pools representing over 800 A. pleuropneumoniae mutants were screened in a natural-host porcine infection model and presumptive attenuated mutants were selected. The identity of the disrupted gene in each mutant was determined using an inverse PCR approach to amplify DNA sequences adjacent to the transposon insertion, followed by sequencing of the PCR product and comparison to bacterial databases. In vitro and in vivo competitive indices were determined for each unique mutant, and a total of 20 unique, attenuating gene disruptions were identified including insertions into homologues of genes involved in biosynthesis, virulence determinants, regulation, translation and unknown functions. Three of the genes required for virulence of A. pleuropneumoniae in this study were also identified in a previous STM study of Pasteurella multocida. Seven of the STM-derived mutants were also evaluated for their potential as live vaccine strains and provided good protection against homologous challenge.

Actinobacillus Infections↗

PubMed1986

Xenotropic virus-related restriction patterns of non-H-2 histocompatibility mutant mice strains.

The relationship between alteration in the number of xenotropic virus-related sequences and non-H-2 histocompatibility (H) mutations in mice was investigated. Mutant classifications included gain, loss, and loss-gain mutations. Genomic DNA from a panel of non-H-2 H mutant strains on the C57BL/6 and BALB/c backgrounds was digested with a set of restriction enzymes with varying numbers of sites within endogenous xenotropic-related sequences. The digested DNA was then resolved on agarose gels. Southern blots of digested DNA were hybridized with the pXenv probe specific for the env sequence of xenotropic viral sequences. The number of hybridizing bands varied from 7 to 19, depending on the restriction enzyme and inbred background. Most mutant strains were identical in their restriction patterns to the respective background strains. However, two B6 mutant strains, KH84 and HZ54, differed from C57BL/6 at a single band which appeared to be inherited from BALB/c in the derivation of the two congenic strains. The HZ43 strain lacked a male-specific band shared by both C57BL/6 and BALB/c; this loss was evidently independent of the original mutation which was observed to be autosomal. However, the KH148B and KH84 strains on the C57BL/6 background lacked single B6 bands. Both mutants were classified as gain mutants. An examination of previous reciprocal graft rejection patterns and retrovirus linkage to non-H-2 H loci indicated a strong inverse relationship between a linked retroviral sequence and presentation of a non-H-2 H antigen. This inverse correlation is consistent with reports of gene inactivation following retroviral insertion.

Animals↗

PubMed1988

Carbon fibre reinforcement for chronic lateral ankle instability.

Flexible carbon fibre implants have been used in 40 cases of chronic ankle instability. The carbon fibre implant permits retention of inversion, does not interfere with peroneal function and is simple to insert. Thirty-seven cases were available for review 46 months after surgery. In 35 cases normal stability had been restored, and 22 patients continued to have an excellent result when reviewed. In 13 cases the implant was subsequently removed, and where no other stabilizing operation was carried out instability recurred. The problems necessitating implant removal have been recognized, and the technique modified to prevent their recurring.

Adult↗

PubMed1991

Yeast artificial chromosome cloning of a two-megabase-size contig within chromosomal band 18q21 establishes physical linkage between BCL2 and plasminogen activator inhibitor type-2.

The construction of large-scale physical maps requires efficient approaches to generate new probes and link informative markers. The mapping of a human chromosomal segment was initiated by using the 18q21.3 probes, plasminogen activator inhibitor type-2 (PLANH2) and BCL2, to screen a yeast artificial chromosome (YAC) library. An inverse polymerase chain reaction technique rescued genomic ends of the YAC inserts. These new probes were used in a chromosomal walking strategy which established that the PLANH2 gene was 600 kb telomeric and in the opposite transcriptional orientation to that of BCL2. Overall, 16 YACs with a mean size of approximately 300 kb were analyzed using rare-cutting restriction endonucleases and 10 end-rescued probes. A contiguous map within 18q21.3 that spans approximately 2 Mb was assembled. This establishes the feasibility of using YACs in the efficient cloning and physical surveying of expanses of the human genome lacking closely spaced, genetic landmarks.

Animals↗