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2 results on '"Laboratory of Chromosome Instability and Dynamics"'

1. The Bracovirus Genome of the Parasitoid Wasp Cotesia congregata Is Amplified within 13 Replication Units, Including Sequences Not Packaged in the Particles

Author

Jean-Michel Drezen, Georges Periquet, Cristina Ferrás, Annie Bézier, Faustine Louis, Catherine Dupuy, Institut de recherche sur la biologie de l'insecte UMR7261 (IRBI), Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), Laboratory of Chromosome Instability and Dynamics, IBMC, and Université de Tours-Centre National de la Recherche Scientifique (CNRS)

Subjects
food.ingredient, Concatemer, Immunology, Molecular Sequence Data, Wasps, Genome, Viral, Biology, Microbiology, Genome, Parasitoid wasp, 03 medical and health sciences, chemistry.chemical_compound, food, Proviruses, Virology, Manduca, Cotesia congregata, Animals, Replicon, Symbiosis, Gene, 030304 developmental biology, Genetics, 0303 health sciences, Base Sequence, 030302 biochemistry & molecular biology, fungi, Gene Amplification, Virion, [SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology, biology.organism_classification, 3. Good health, Genome Replication and Regulation of Viral Gene Expression, chemistry, Polydnaviridae, Insect Science, DNA, Viral, Nucleic Acid Conformation, Female, Bracovirus, DNA
Abstract

The relationship between parasitoid wasps and polydnaviruses constitutes one of the few known mutualisms between viruses and eukaryotes. Viral particles are injected with the wasp eggs into parasitized larvae, and the viral genes thus introduced are used to manipulate lepidopteran host physiology. The genome packaged in the particles is composed of 35 double-stranded DNA (dsDNA) circles produced in wasp ovaries by amplification of viral sequences from proviral segments integrated in tandem arrays in the wasp genome. These segments and their flanking regions within the genome of the wasp Cotesia congregata were recently isolated, allowing extensive mapping of amplified sequences. The bracovirus DNAs packaged in the particles were found to be amplified within more than 12 replication units. Strikingly, the nudiviral cluster, the genes of which encode particle structural components, was also amplified, although not encapsidated. Amplification of bracoviral sequences was shown to involve successive head-to-head and tail-to-tail concatemers, which was not expected given the nudiviral origin of bracoviruses.

Published
2013
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2. Expression analysis of MLH3, MLH1, and MSH4 in maturation arrest.

Author

Ferrás C, Fernandes S, Silva J, Barros A, and Sousa M

Subjects
Azoospermia genetics, Azoospermia metabolism, Chromosomes, Human, Y genetics, DNA blood, DNA Mutational Analysis, Gene Deletion, Gene Expression, Humans, Male, Meiosis, Microsatellite Instability, MutL Protein Homolog 1, MutL Proteins, Spermatocytes metabolism, Adaptor Proteins, Signal Transducing genetics, Azoospermia pathology, Carrier Proteins genetics, Cell Cycle Proteins genetics, DNA Mismatch Repair genetics, Nuclear Proteins genetics, Spermatocytes pathology
Abstract

The expression of DNA mismatch repair (DMMR) genes in patients with maturation arrest (MA) was analyzed. Samples were subjected to mutL homolog 3 (MLH3) mutation analysis by denaturing high-performance liquid chromatography/sequencing and quantification of MMR expression in testicular tissue by real-time polymerase chain reaction (PCR). Microsatellite instability assays were negative. Two missense and 1 intronic mutations were found. The missense mutation 2531C/T (P844 L), predicted to affect MLH3 function, was found in 3 MA cases in association with the intronic variant IVS9 + 66G/A. Relative messenger RNA (mRNA) quantification identified 2 patients who overexpressed MLH3, 1 of them also overexpressing mutL homolog 1 (MLH1). The latter also presented the 2531C/T-IVS9 + 66G/A mutation. In conclusion, we suggest that a predominance of MLH3 expression might favor the MLH1/MLH3 complex which then would compete with the MLH1/PMS2 complexes. This could convey disruption of the relative stoichiometry between MLH1/MLH3 and MLH1/PMS2 complexes, thus causing meiosis failure, as MLH1/PMS2 complexes are supposed to replace MLH1/MLH3 during diplonema.

Published
2012
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