Search results for "Direct repeat"
showing 8 items of 8 documents
In vitro evolution of an atrazine-degrading population under cyanuric acid selection pressure: Evidence for the selective loss of a 47kb region on th…
2011
International audience; The adaptation of microorganisms to pesticide biodegradation relies on the recruitment of catabolic genes by horizontal gene transfer and homologous recombination mediated by insertion sequences (IS). This environment-friendly function is maintained in the degrading population but it has a cost which could diminish its fitness. The loss of genes in the course of evolution being a major mechanism of ecological specialization, we mimicked evolution in vitro by sub-culturing the atrazine-degrading Pseudomonas sp. ADP in a liquid medium containing cyanuric acid as the sole source of nitrogen. After 120 generations, a new population evolved, which replaced the original on…
Fast Isolation by AFLP of Sequences Containing Repeats
2013
Fast isolation by AFLP of sequences containing repeats (FIASCO) is a rapid and simple method for separating microsatellite-containing DNA fragments from genomic DNA de novo. The method takes the advantage of the amplified fragment length polymorphism (AFLP) technique that relies on effective digestion-ligation reaction. The repeat-containing fragments are selectively hybridized to biotinylated probes and harvested by streptavidin-coated magnetic beads. The enriched microsatellite-containing fragments can be cloned and sequenced to yield a variety of microsatellite loci for applications in many different fields in molecular genetics.
Requirement of the Lactobacillus casei MaeKR two-component system for L-malic acid utilization via a malic enzyme pathway.
2009
ABSTRACTLactobacillus caseican metabolizel-malic acid via malolactic enzyme (malolactic fermentation [MLF]) or malic enzyme (ME). Whereas utilization ofl-malic acid via MLF does not support growth, the ME pathway enablesL. caseito grow onl-malic acid. In this work, we have identified in the genomes ofL. caseistrains BL23 and ATCC 334 a cluster consisting of two diverging operons,maePEandmaeKR, encoding a putative malate transporter (maeP), an ME (maeE), and a two-component (TC) system belonging to the citrate family (maeKandmaeR). Homologous clusters were identified inEnterococcus faecalis,Streptococcus agalactiae,Streptococcus pyogenes, andStreptococcus uberis. Our results show that ME is …
Construction of a Trp commercial baker?s yeast strain by using food-safe-grade dominant drug resistance cassettes
2003
We have designed a food-safe-grade module for gene disruptions in commercial baker's yeast strains, which contains the G418 resistance cassette, KanMX4, flanked by direct repeats from the MEL1 gene of Saccharomyces cerevisiae. This module was used to obtain a Trp(-) auxotrophic mutant of the polyploid HY strain by successive targeting to the TRP1 locus and later in vivo excision of the kan(r) marker. Southern blot analysis indicated that HY contains five copies of the TRP1 gene. However, after four disruption rounds, a strain named HYtrpM(4), unable to grow in the absence of tryptophan, was selected. Southern and Northern analysis of HYtrpM(4) cells showed that a remaining functional wild-t…
Intronic L1 insertion and F268S, novel mutations in RPS6KA3 (RSK2) causing Coffin-Lowry syndrome
2003
Two novel mutations of the ribosomal S6 kinase 2 gene (also known as RSK2) have been identified in two unrelated patients with Coffin–Lowry syndrome. The first mutation consists of a de novo insertion of a 5′-truncated LINE-1 element at position −8 of intron 3, which leads to a skipping of exon 4, leading to a shift of the reading frame and a premature stop codon. The L1 fragment (2800 bp) showed a rearrangement with a small deletion, a partial inversion of the ORF 2, flanked by short direct repeats which duplicate the acceptor splice site. However, cDNA analysis of the patient shows that both sites are apparently not functional. The second family showed the nucleotide change 803T>C in exon…
Fitness drift of an atrazine-degrading population under atrazine selection pressure.
2008
International audience; Pseudomonas sp. ADP harbouring the atrazine catabolic plasmid ADP1 was subcultured in liquid medium containing atrazine as sole source of nitrogen. After approximately 320 generations, a new population evolved which replaced the initial population. This newly evolved population grew faster and degraded atrazine more rapidly than the initial population. Plasmid profiles and Southern blot analyses revealed that the evolved strain, unlike the ancestral strain, presented a tandem duplication of the atzB gene encoding the second enzyme of the atrazine catabolic pathway responsible for the transformation of hydroxyatrazine to N-isopropylammelide. This duplication resulted …
Drosophila melanogaster histone H2B retropseudogene is inserted into a region rich in transposable elements.
1998
We have isolated and characterized the genomic sequence of a Drosophila melanogaster histone H2B pseudogene that is localized outside of the cluster of the replication-dependent histone genes and has all the properties of a retropseudogene. It is highly homologous to the transcribed region of the D. melanogaster histone H2B gene, but not to its flanking regions, and is surrounded by short direct repeats. The pseudogene contains several point mutations that preclude its translation. The sequence of the 3' region of this pseudogene is compatible with the hypothesis that the 3' terminal stem-loop structure of the histone H2B mRNA has served as a primer for the reverse transcription event from …
The Mu1 transposable element of maize contains two promoter signals recognized by the Escherichia coli RNA polymerase.
1990
The galactokinase (GalK) expression plasmid vector system pKO-1 has been used to screen for promoter elements in the maize transposable element Mu1 that function in Escherichia coli. Two transcriptional start points, named S1 and S2, were identified, which are located in the two direct repeats of the transposable element. This paper demonstrates that sequence elements exist in a plant transposable element which function as prokaryotic promotors.