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Ortholog Gene (ortholog + gene)

Distribution by Scientific Domains

Life Sciences	50%

Selected Abstracts

Assessment of the Two Helicobacter pylori ,-1,3-Fucosyltransferase Ortholog Genes for the Large-Scale Synthesis of LewisX Human Milk Oligosaccharides by Metabolically Engineered Escherichia coli

BIOTECHNOLOGY PROGRESS, Issue 2 2004
Claire Dumon
We previously described a bacterial fermentation process for the in vivo conversion of lactose into fucosylated derivatives of lacto- N -neotetraose Gal(,1,4)GlcNAc(,1,3)Gal(,1,4)Glc (LNnT). The major product obtained was lacto- N -neofucopentaose-V Gal(,1,4)GlcNAc(,1,3)Gal(,1,4)[Fuc(,1,3)]Glc, carrying fucose on the glucosyl residue of LNnT. Only a small amount of oligosaccharides fucosylated on N -acetylglucosaminyl residues and thus carrying the LewisX group (LeX) was also produced. We report here a fermentation process for the large-scale production of LeX oligosaccharides. The two fucosyltransferase genes futA and futB of Helicobacter pylori (strain 26695) were compared in order to optimize fucosylation in vivo. futA was found to provide the best activity on the LNnT acceptor, whereas futB expressed a better LeX activity in vitro. Both genes were expressed to produce oligosaccharides in engineered Escherichia coli ( E. coli) cells. The fucosylation pattern of the recombinant oligosaccharides was closely correlated with the specificity observed in vitro, FutB favoring the formation of LeX carrying oligosaccharides. Lacto- N -neodifucohexaose-II Gal(,1,4)[Fuc(,1,3)]GlcNAc(,1,3)Gal(,1,4)[Fuc(,1,3)]Glc represented 70% of the total oligosaccharide amount of futA -on-driven fermentation and was produced at a concentration of 1.7 g/L. Fermentation driven by futBled to equal amounts of both lacto- N -neofucopentaose-V and lacto- N -neofucopentaose-II Gal(,1,4)[Fuc(,1,3)]GlcNAc(,1,3)Gal(,1,4)Glc, produced at 280 and 260 mg/L, respectively. Unexpectedly, a noticeable proportion (0.5 g/L) of the human milk oligosaccharide 3-fucosyllactose Gal(,1,4)[Fuc(,1,3)]Glc was produced in futA -on-driven fermentation, underlining the activity of fucosyltransferase FutA in E.coli and leading to a reassessment of its activity on lactose. All oligosaccharides produced by the products of both fut genes were natural compounds of human milk. [source]

Genomic structure and expression analysis of the RNase , family ortholog gene in the insect Ceratitis capitata

FEBS JOURNAL, Issue 24 2008
Theodoros N. Rampias
Cc RNase is the founding member of the recently identified RNase , family, which is represented by a single ortholog in a wide range of animal taxonomic groups. Although the precise biological role of this protein is still unknown, it has been shown that the recombinant proteins isolated so far from the insect Ceratitis capitata and from human exhibit ribonucleolytic activity. In this work, we report the genomic organization and molecular evolution of the RNase , gene from various animal species, as well as expression analysis of the ortholog gene in C. capitata. The high degree of amino acid sequence similarity, in combination with the fact that exon sizes and intronic positions are extremely conserved among RNase , orthologs in 15 diverse genomes from sea anemone to human, imply a very significant biological function for this enzyme. In C. capitata, two forms of RNase , mRNA (0.9 and 1.5 kb) with various lengths of 3, UTR were identified as alternative products of a single gene, resulting from the use of different polyadenylation signals. Both transcripts are expressed in all insect tissues and developmental stages. Sequence analysis of the extended region of the longer transcript revealed the existence of three mRNA instability motifs (AUUUA) and five poly(U) tracts, whose functional importance in RNase , mRNA decay remains to be explored. [source]

Molecular analysis of the serine/threonine kinase Akt and its expression in the mosquito Aedes aegypti

INSECT MOLECULAR BIOLOGY, Issue 3 2003
M. A. Riehle
Abstract A key component of the insulin-signalling pathway, the protein kinase Akt, was identified and cloned as a cDNA from ovaries of the mosquito Aedes aegypti. An ortholog gene was found in the Anopheles gambiae genome database, and like other Akts, both mosquito Akts possess pleckstrin homology domains for membrane binding and a serine/threonine kinase domain. When Ae. aegypti ovaries were treated with bovine insulin in vitro, a putative Akt was threonine-phosphorylated, as expected for Akts. AaegAKT was only expressed in embryos for the first 6 h after oviposition and in ovaries before and during a gonotrophic cycle. [source]