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A Blanchetot

Publications and source records attributed to A Blanchetot.

17 recordsLinked to original sources
PubMed2002

PCV2 replicase transcripts in infected porcine kidney (PK15) cells.

The Circoviridae family includes small viruses containing circular single strand DNA. There are two circoviruses described in pigs. Porcine Circovirus 2 (PCV2) has been linked to a disease termed Postweaning Multisystemic Wasting Syndrome (PMWS) whereas a close relative of this virus, termed PCV type 1 (PCV1) has been considered a non-pathogenic contaminant of the PK15 cell line. Rolling circle replication of small DNA viruses like circoviruses is mediated by a replicase (Rep) gene that is transcribed into different mRNAs by an alternative splicing mechanism. In PCV1, two transcripts Rep and Rep' implicated in DNA replication, have been identified from infected cells. These transcripts are the product of a single gene with Rep' having a different carboxyl end than Rep. Sequence comparison shows that there is a high degree of homology for the Rep gene in both viruses. In this article, we have identified three different transcripts by RT-PCR in PCV2 infected PK15 cells. Two of them have homology with their PCV1 counterparts and the third transcript, termed Rep", corresponds to another spliced version of the Rep gene. This transcript, unique to PCV2, encodes for a protein of 80 aminoacids in frame with the Rep sequence.

Amino Acid Sequence↗
PubMed2000

Representational differential analysis detects amplification of satellite sequences in postweaning multisystemic wasting syndrome of pigs.

Representational difference analysis (RDA) was used as a molecular approach to identify unique sequences associated with postweaning multisystemic wasting syndrome (PMWS) in pigs. Three rounds of subtractive hybridization and amplification between driver DNA extracted from normal pigs and tester DNA from PMWS-affected animals were performed. The final product corresponding to sequences associated with PMWS in pigs was analyzed using agarose gel electrophoresis, and 9 fragments were visualized after staining with ethidium bromide. Eight recombinants were successively cloned and sequenced, and the results were then compared with existing databases. Most of the PMWS clones isolated were satellite sequences from pig centrometric regions and 1 was a microsatellite sequence. One clone represented a microsatellite sequence, and 2 clones showed no homology with any gene found in the databases. The sequence comparison data did not reveal any homology with an infectious agent such as a virus or a bacterium. In the present experimental setting, it was concluded that PMWS in pigs triggers molecular changes such as an amplification of genomic regions containing repeated sequences.

Animals↗
PubMed1995

Identification of a mariner element from the tsetse fly, Glossina palpalis palpalis.

In the present study, the polymerase chain reaction was used initially to demonstrate the presence of mariner sequences in seven species/subspecies of tsetse flies. DNA hybridization experiments show mariner sequences to be dispersed within the tsetse genome and that there are large variations in copy numbers among the various taxa. A genomic library was used to isolate and characterize a full-length mariner element from G. p. palpalis. The results indicate that this element is 1257 bp in length, flanked by two 32 bp inverted repeats differing at only one position, and belongs to the mellifera subfamily. The nucleotide sequence that is translated into a reading frame of 337 amino acids requires the introduction of two frame shifts and one stop codon to maximize sequence homology with a mariner element from Drosophila erecta. Based on this evidence, we conclude that the G. p. palpalis mariner element clearly represents a non-functional transposable element and that the protein product is not an active transposase.

Amino Acid Sequence↗
PubMed1994

Isolation and characterization of hypervariable sequences from tsetse fly genome.

A Glossina brevipalpis Newstead genomic library, constructed using a Charomid 9-36 vector, was used to isolate putative clones that hybridize to polymorphic regions of the tsetse genome. Five types of probes, that reveal individual DNA polymorphic in humans and higher animal species, were used to screen 300 tsetse Charomid clones; 15% of the clones hybridized with at least one probe. Twenty four recombinants were further characterized by Southern blotting hybridization using DNA isolated from individual tsetse fly from Glossina morsitans centralis Machado. Two classes of DNA profiles were obtained upon hybridization with the recombinant inserts. The first, termed the "multilocus profile" displayed a complex DNA pattern of multiple components whilst the second, referred to as the "single locus profile" revealed one or two bands in each individual. Of the 24 recombinant inserts tested, 13 were multilocus probes and the remainder were single locus probes, each of which hybridized to a single location when G. m. centralis DNA had been cleaved with EcoRI. These single locus probes revealed a low level of genetic variability among individual flies from an inbred colony. The hybridization profiles using multilocus and single locus probes were also obtained on DNA from individual Glossina palpalis palpalis Robineau-Desvoidy and Glossina palpalis gambienis Vanderplank and some of the G. brevipalpis recombinant clones also detected multilocus profiles in honey bees and man.

Animals↗
PubMed1994

Genetic variability and segregation analysis in Glossina moristans moristans (Diptera: Glossinidae) using DNA fingerprinting.

DNA hybridization, using the M13 sequence as a probe, was used to analyze the genetic variability in four inbred lines of the tsetse fly Glossina morsitans morsitans Westwood. An average of 11.2 bands (ranging from 2 to 10 kb) were found per fly. An average of nine loci were detected in each line; 40% of the loci were polymorphic and the mean heterozygosity per locus varied from 0.098 to 0.29. Averaging the data across the four inbred lines, the band sharing estimates were 82.5% in males and 81.2% in females, and the mean band frequency estimates were 0.71 and 0.70 for males and females, respectively. Segregation of fragments, determined in "three generation" pedigrees, conformed to expected Mendelian ratios and two of seven fragments studied were linked to an X chromosome marker gene, ocra (body color).

Animals↗
PubMed1993

Genetic analysis by DNA fingerprinting in tsetse fly genomes.

Genomic DNA from tsetse flies (Diptera: Glossinidae: Glossina Wiedemann) was analyzed by hybridization using the whole M13 phage as a probe to reveal DNA fingerprinting (DNAfp) profiles. Intrapopulation variability, measured by comparison of DNAfp profiles of tsetse flies from a large colony of G. brevipalpis, showed a high degree of polymorphism similar to that found in other animal species. Different lines of G. m. morsitans, G. m. centralis, G. m. submorsitans, G. p. palpalis and G. p. gambiensis established from small colonies displayed less genetic variability than the G. brevipalpis population. The analysis of pedigree relationships within an inbred line of G. m. centralis conformed to a Mendelian inheritance pattern. In the pedigree presented no mutations were observed, one fragment was linked to the X chromosome, and three fragment sets were linked, but most fragments showed independent segregation. M13 revealed no characteristic DNAfp profile differences between the subgenus Glossina and the subgenus Nemorhina, but a conserved distribution pattern was found in the laboratory colonies within each subspecies. M13 also revealed line specific DNA fragments that may be useful as genetic markers to expand the present linkage map of G. m. morsitans.

Animals↗
PubMed1992

Genetic variability in the social bee Lasioglossum marginatum and a cryptic undescribed sibling species, as detected by DNA fingerprinting and allozyme electrophoresis.

DNA fingerprints (DNAfp) were obtained for three widely separated samples of bee related to Lasioglossum marginatum using the M13 sequence as a probe. Bee samples were obtained from France (three localities separated by at most 20 km), Greece and India. All European populations exhibited almost identical profiles with similarity indices (S) of over 98% within a French sample, 94% among Greek bees and 90% between Greek and French bees. The DNAfp profiles of Indian bees showed more polymorphism (intrapopulation S = 77%) and were quite dissimilar to the European samples (S = 55% and 56% to French and Greek samples, respectively). The similarity between populations separated by over 2000 km is higher than among unrelated individuals within a population in two other bee species and the tsetse fly. Data from allozyme electrophoresis shows parallel variation to that obtained with DNAfp and the genetic differences between Indian and European samples are strikingly large (Indian and European populations shared no alleles at 14 out of 47 loci surveyed) such that no more than one species must be involved. Nonetheless, the samples are indistinguishable morphologically. We argue that chronically low effective population size in these species results in low levels of genetic variability and that this, combined with a genetic bottleneck during the speciation event and colonization of Europe, may have resulted in both the extremely low levels of DNAfp variation in European bees and the large number of fixed allelic differences between European and Indian samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

DNA fingerprinting analysis in the solitary bee Megachile rotundata: variability and nest mate genetic relationships.

The most conventional approach for evaluating genetic variability in an insect population involves assessing the degree of enzyme polymorphism. Hymenoptera display a relatively low level of genetic variability compared with most insect species. DNA probes consisting of tandemly repeated sequences are powerful tools for detecting polymorphisms when employed to develop DNA fingerprinting (DNAfp) profiles in a wide range of organisms. This report describes genetic variability in the solitary bee species Megachile rotundata as assessed by DNAfp using the M13 sequence and a synthetic oligonucleotide sequence homologous to a hypervariable region of the alpha-globin gene. DNAfp comparisons among offspring were used to analyze genealogical structure in M. rotundata nests. The results indicate that polyandry, by a large number of males, is not a common phenomenon in M. rotundata bee species. In the present analysis, it is likely that the broods raised in single nests are mostly the offspring of one singly mated female. However, the data does not preclude that for certain nests two males could have been involved in the mating process.

Animals↗
PubMed1991

A Musca domestica satellite sequence detects individual polymorphic regions in insect genome.

A recombinant plasmid, pHMd.24, was constructed which contains an array of a 24 bp sequence from the genome of the Musca domestica. This sequence hybridizes to sites occurring at various genomic locations in different housefly strains. The pHMd.24 insert has a structural organisation similar to satellite DNA sequences and hybridizes to homologous repeated sequences representing a small fraction of the M. domestica genome. Interestingly, this clone reveals polymorphic fragments from DNA isolated from single houseflies, thus generating an insect DNA fingerprint. In addition, the segregation of the fragments detected by hybridisation in a M. domestica pedigree indicates a transmission that follows mendelian inheritance.

Animals↗
PubMed1991

Genetic variability of a satellite sequence in the dipteran Musca domestica.

A Musca domestica satellite sequence that hybridizes to multiple sites in the the genome has been characterised. The cloned sequence, with a structural organisation similar to other satellite DNA, contains at least 50 repeats of a 24 bp unit. This insect-specific satellite hybridizes to sites occurring at different locations and represents only a minor fraction of the M. domestica genome. Polymorphic fragments from DNA isolated from single houseflies have been obtained, generating individual specific DNA fingerprints. In addition, pedigree analysis confirms that the DNA fingerprint fragments are inherited in a Mendelian fashion and originate from multiple, apparently dispersed, loci.

Animals↗
PubMed1986

The mouse myoglobin gene. Characterisation and sequence comparison with other mammalian myoglobin genes.

Seal myoglobin (Mb) exons 1 and 3 were used as probes to isolate the functional mouse Mb gene. This gene has a very low level of Mb expression in skeletal muscle. Although it is shorter, the mouse Mb gene displays the common organisation found in human and seal Mb genes. In addition, we have defined blocks of conserved sequences in the 5' flanking region by comparison with other mammalian Mb genes. Moreover, about 10(3) bases upstream of the cap site we identified a repetitive B1 element directly associated with two overlapping open reading frames, containing a putative polyadenylation signal. A polypyrimidine-rich region has also been located upstream from the gene.

Animals↗
PubMed1984

The human myoglobin gene: a third dispersed globin locus in the human genome.

Human myoglobin is specified by a single gene. Unique sequence DNA probes were isolated from the cloned gene and used to test for the presence of the human myoglobin gene in a series of human rodent somatic cell hybrids containing various complements of human chromosomes. The myoglobin gene cosegregated with human chromosome 22. Somatic cell hybrids containing translocation chromosomes carrying part of chromosome 22 were used to locate the myoglobin gene to the region 22q11----22q13. The myoglobin gene is therefore not linked to the alpha-globin gene cluster on chromosome 16 or the beta-globin cluster on chromosome 11, and represents a third dispersed globin locus in the human genome.

Animals↗
PubMed1984

Metabolism of tRNA in near-ultraviolet-illuminated Escherichia coli. The tRNA repair hypothesis.

The relA+-dependent stringent response is an important component of the mechanism of the near-ultraviolet-induced growth delay. However, the behaviour of the intracellular level of ppGpp is unexpected [Thomas et al. (1981) Eur. J. Biochem. 118, 381-387] and this led us to examine the metabolism of tRNAs during the illumination period and the growth lag that follows. Analysis of the gel electrophoresis migration profiles of tRNA molecules, synthesized prior to the illumination period, provides no evidence for tRNA degradation. Rather, it is suggestive of the rearrangement of some cross-linked tRNA species during the growth lag. By the same technique the neosynthesis of one or several tRNA species escaping the stringent response could be ruled out at the beginning of the growth lag. The behaviour of the cross-linked tRNAs was followed by a chromatographic procedure allowing the quantitative evaluation of the 8-13 link present in vivo. Upon illumination of growing cells, one observes an initial linear increase of the 8-13 link content. Unexpectedly this is followed during the illumination period by an abrupt decrease. The 8-13 link content then remains stable. The data above suggest that part of the 8-13 link (25-40%) is eliminated from tRNA without degradation of the molecules involved. A tRNA repair hypothesis is proposed: elimination of the 8-13 link would occur by scission of the N1-C1' glycosidic bonds at positions 8 and 13 of tRNA. It would be followed by reinsertion of uracil and cytosine in their respective positions.

Binding Sites↗
PubMed1984

Organization of the human myoglobin gene.

Cross-hybridization of the grey seal myoglobin gene to human DNA detected a single human myoglobin gene plus an extensive family of sequences apparently related to the central exon of this gene. The functional human gene is 10.4 kb long and has a haemoglobin-like three exon/two intron structure with long non-coding regions similar to its seal homologue. At least 300 bp of 5'-flanking region are closely homologous between the two genes, with the exception of a divergent purine-rich region 68-114 bp upstream of the cap site. A diverged tandem repetitive sequence based on (GGAT)165 is located 1100-1750 bp upstream from the gene; internal homology units within this sequence suggest sequence homogenization by gene microconversions. A second 33-bp tandem repeat element in the first intron is flanked by a 9-bp direct repeat, shares homology with other tandem repetitive elements in the human genome and may represent a novel form of transposable element.

Animals↗
PubMed1983

The seal myoglobin gene: an unusually long globin gene.

The tetrameric haemoglobins of vertebrates are encoded by alpha- and beta-globin gene families which arose during evolution by a succession of gene duplications, commencing with an alpha beta globin gene duplication which occurred about 500 Myr ago, early in the evolution of the vertebrates. All functional alpha- and beta- globin genes analysed so far share common features, including coding sequence homologies and the presence of two introns within the coding sequence at locations which correlate with interdomain boundaries within globin polypeptides. Here we describe the isolation and characterization of an additional diverged member of the globin gene family, the seal myoglobin gene. We show that monomeric myoglobin, which diverged from haemoglobin about 600-800 Myr ago before the appearance of tetrameric haemoglobins, is also specified by a gene containing two introns at positions precisely homologous to haemoglobin introns. Unlike vertebrate haemoglobin genes, however, the noncoding regions of the seal myoglobin gene are remarkably long.

Amino Acid Sequence↗
PubMed1982

Molecular cloning of seal myoglobin mRNA.

Grey seal skeletal muscle containing high levels of myoglobin was used to prepare poly(A)+ RNA. In vitro translation of this RNA produced a range of polypeptides including myoglobin. cDNA was prepared by reverse transcription of muscle poly(A)+ RNA and cloned into the plasmid pAT 153. 4% of cDNA recombinants were shown to contain myoglobin cDNA inserts. DNA sequence analysis of one clone (pSM 178) which contained a relatively large myoglobin cDNA insert showed an incomplete cDNA comprising the terminal 293 nucleotides of 3' non-translated mRNA sequences. Hybridization experiments using this myoglobin cDNA indicated that seal myoglobin is coded by a single gene which is transcribed to give a 1400 nucleotide mRNA considerably longer than related haemoglobin mRNAs.

Animals↗