Benjamin Lacroix

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Polyglutamylation is a posttranslational modification that generates glutamate side chains on tubulins and other proteins. Although this modification has been shown to be reversible, little is known about the enzymes catalyzing deglutamylation. Here we describe the enzymatic mechanism of protein deglutamylation by members of the cytosolic carboxypeptidase(More)
Polyglutamylases are enzymes that form polyglutamate side chains of variable lengths on proteins. Polyglutamylation of tubulin is believed to regulate interactions of microtubules (MTs) with MT-associated proteins and molecular motors. Subpopulations of MTs are differentially polyglutamylated, yet only one modifying enzyme has been discovered in mammals. In(More)
Posttranslational glutamylation of tubulin is present on selected subsets of microtubules in cells. Although the modification is expected to contribute to the spatial and temporal organization of the cytoskeleton, hardly anything is known about its functional relevance. Here we demonstrate that glutamylation, and in particular the generation of long(More)
Two Norway spruce (Picea abies Karst.) clones, one resistant and the other susceptible to mass inoculation with Ophiostoma polonicum Siem., were compared with regard to their phenolic compositions and chalcone synthase (CHS) and stilbene synthase activities of their phloem before and at 6 and 12 d after artificial inoculation with sterile malt agar or O.(More)
A solution to the problem of library screening is analysed. We examine how to retrieve those clones that are positive for a single copy landmark from a whole library while performing only a minimum number of laboratory tests: the clones are arranged on a matrix (i.e in 2 dimensions) and pooled according to the rows and columns. A fingerprint is determined(More)
In order to study the effect of glucose on the differentiation of cultured human colon cancer cells, a subpopulation of HT-29 cells was selected for its capacity to grow in the total absence of sugar. These cells (Glc-cells) exhibit, after confluency, an enterocytic differentiation, in contrast to cells grown with glucose (Glc+ cells), which always remain(More)
The present study is concerned with a multilevel approach to human colon organogenesis, involving scanning and transmission electron microscopy together with brush border enzymology. The results emphasize the particular developmental pattern of sucrase activity which appears towards 11 weeks, increases at 14 weeks, begins to decrease around 28 weeks and(More)
An experimental model was designed to analyze the effect of fetal gut mesenchyme on the cytodifferentiation of crypt cells and of embryonic progenitor cells. The cells used were the rat intestinal crypt cell line, IEC-17, and primary cell cultures prepared form isolated 14-day-old fetal intestinal endoderm (EC). Both cultures prepared from isolated(More)
The microtubule-associated protein TOGp, which belongs to a widely distributed protein family from yeasts to humans, is highly expressed in human tumors and brain tissue. From purified components we have determined the effect of TOGp on thermally induced tubulin association in vitro in the presence of 1 mm GTP and 3.4 m glycerol. Physicochemical parameters(More)
Physical mapping of the human genome has until now been envisioned through single chromosome strategies. We demonstrate that by using large insert yeast artificial chromosomes (YACs) a whole genome approach becomes feasible. YACs (22,000) of 810 kb mean size (5 genome equivalents) have been fingerprinted to obtain individual patterns of restriction(More)