Characterization of a radish introgression carrying the Ogura fertility restorer gene Rfo in rapeseed,using the Arabidopsis genome sequence and radish genetic mapping

The radish Rfo gene restores male fertility in radish or rapeseed plants carrying Ogura cytoplasmic male-sterility. This system was first discovered in radish and was transferred to rapeseed for the production of F1 hybrid seeds. We aimed to identify the region of the Arabidopsis genome syntenic to the Rfo locus and to characterize the radish introgression in restored rapeseed. We used two methods: amplified consensus genetic markers (ACGMs) in restored rapeseed plants and construction of a precise genetic map around the Rfo gene in a segregating radish population. The use of ACGMs made it possible to detect radish orthologs of Arabidopsis genes in the restored rapeseed genome. We identified radish genes, linked to Rfo in rapeseed and whose orthologs in Arabidopsis are carried by chromosomes 1, 4 and 5. This indicates several breaks in colinearity between radish and Arabidopsis genomes in this region. We determined the positions of markers relative to each other and to the Rfo gene, using the progeny of a rapeseed plant with unstable meiotic transmission of the radish introgression. This enabled us to produce a schematic diagram of the radish introgression in rapeseed. Markers which could be mapped both on radish and restored rapeseed indicate that at least 50 cM of the radish genome is integrated in restored rapeseed. Using markers closely linked to the Rfo gene in rapeseed and radish, we identified a contig spanning six bacterial artificial chromosome (BAC) clones on Arabidopsis chromosome 1, which is likely to carry the orthologous Rfo gene.Electronic Supplementary Material Supplementary material is available in the online version of this article at Communicated by H. C. BeckerS. Giancola and S. Marhadour contributed equally to this work     

Fusion with the fused: a new role for interleukin-4 in the building of muscle

In this issue of Cell, G. Pavlath and coworkers demonstrate a novel role for Interleukin-4 (IL-4) in regulating the fusion of myoblasts with differentiated myotubes. The authors demonstrate that NFATc2 signaling in newly formed myotubes induces IL-4 expression and secretion which promotes myoblast fusion with pre-existing myotubes.     

Kinetic study of azole-bridged dinuclear platinum(II) complexes reacting with a hairpin-stabilized double-stranded oligonucleotide

The cytotoxic dinuclear platinum(II) complexes [[cis-Pt(NH(3))(2)](2)(mu-OH)(mu-pz)](NO(3))(2) (pz=pyrazolate) (1) and [[cis-Pt(NH(3))(2)](2)(mu-OH)(mu-1,2,3-ta-N1,N2)](NO(3))(2) (1,2,3-ta=1,2,3-triazolate) (2), were allowed to react with the hairpin-stabilized double-stranded oligonucleotide d(TATGGCATT(4)ATGCCATA), to determine the amounts of intrastrand and interstrand DNA adducts. The reaction kinetics was investigated by reversed-phase HPLC, and the resulting products were analyzed using mass spectroscopy combined with enzymatic digestion, and Maxam-Gilbert sequencing. The reaction of 1 results in the formation of the 1,2-intrastrand d(GG) adduct as the major final product. The two most abundant products of 2 were identified as isomeric 1,2-intrastrand d(GG) adducts differing probably in platinum coordination to the triazole ring. No GG-interstrand crosslinks were detected with either compound. d(GGC)-d(GCC) sequences of DNA do thus not appear to represent significant targets for forming interstrand crosslinks with either 1 or 2.     

Proteomics application exercise of the Swiss Proteomics Society: report of the SPS'02 session

After the success of the mass spectrometry (MS) round table that was held at the first Swiss Proteomics Society congress (SPS'01) in Geneva, the SPS has organized a proteomics application exercise and allocated a full session at the SPS'02 congress. The main objective was to encourage the exchange of expertise in protein identification, with a focus on the use of mass spectrometry, and to create a bridge between the users' questions and the instrument providers' solutions. Two samples were sent to fifteen interested labs, including academic groups and MS hardware providers. Participants were asked to identify and partially characterize the samples. They consisted of a complex mixture of peptide/proteins (sample A) and an almost pure recombinant peptide carrying post-translational modifications (sample B). Sample A was an extract of snake venom from the species Bothrops jararaca. Sample B was a recombinant and modified peptide derived from the shrimp Penaeus vannamei penaeidin 3a. The eight labs that returned results reported the use of a wide range of MS instrumentation and techniques. They mentioned a variety of time and manpower allocations. The origin of sample A was generally identified together with a number of database protein entries. The difficulty of the sample identification lay in the incomplete knowledge of the Bothrops species genome sequence and is discussed. Sample B was generally and correctly identified as penaeidin. However, only one group reported the full primary structure. Interestingly, the approaches were again varied and are discussed in the text.     

Shorebird community variations indicative of a general perturbation in the Mont-Saint-Michel bay (France)

The Mont-Saint-Michel bay located on the East Atlantic Flyway is the first site in France for wintering shorebirds, with, on average, 53,000 individuals in January. Seven species represent 96% of that community: dunlin (Calidris alpina), knot (Calidris canutus), oystercatcher (Haematopus ostralegus), curlew (Numenius arquata), grey plover (Pluvialis squatarola), bar-tailed godwit (Limosa lapponica) and black-tailed godwit (Limosa limosa). The international bird census organised by Wetlands International in mid-January gave us the opportunity to study, for a 23 years period, population variations in the bay. Despite a quite good carrying capacity, we showed that the decreasing proportion of 4 species in the bay relative to the other French populations may indicate a general perturbation of the bay. We discuss the different hypotheses to explain that observation.     

Association of the Golgi UDP-galactose transporter with UDP-galactose:ceramide galactosyltransferase allows UDP-galactose import in the endoplasmic reticulum

UDP-galactose reaches the Golgi lumen through the UDP-galactose transporter (UGT) and is used for the galactosylation of proteins and lipids. Ceramides and diglycerides are galactosylated within the endoplasmic reticulum by the UDP-galactose:ceramide galactosyltransferase. It is not known how UDP-galactose is transported from the cytosol into the endoplasmic reticulum. We transfected ceramide galactosyltransferase cDNA into CHOlec8 cells, which have a defective UGT and no endogenous ceramide galactosyltransferase. Cotransfection with the human UGT1 greatly stimulated synthesis of lactosylceramide in the Golgi and of galactosylceramide in the endoplasmic reticulum. UDP-galactose was directly imported into the endoplasmic reticulum because transfection with UGT significantly enhanced synthesis of galactosylceramide in endoplasmic reticulum membranes. Subcellular fractionation and double label immunofluorescence microscopy showed that a sizeable fraction of ectopically expressed UGT and ceramide galactosyltransferase resided in the endoplasmic reticulum of CHOlec8 cells. The same was observed when UGT was expressed in human intestinal cells that have an endogenous ceramide galactosyltransferase. In contrast, in CHOlec8 singly transfected with UGT 1, the transporter localized exclusively to the Golgi complex. UGT and ceramide galactosyltransferase were entirely detergent soluble and form a complex because they could be coimmunoprecipitated. We conclude that the ceramide galactosyltransferase ensures a supply of UDP-galactose in the endoplasmic reticulum lumen by retaining UGT in a molecular complex.     

Reinvestigation of the <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> genome annotation by comparison to the genome of a related fungus: <Emphasis Type="Italic">Ashbya gossypii</Emphasis>

Background  

The recently sequenced genome of the filamentous fungus Ashbya gossypii revealed remarkable similarities to that of the budding yeast Saccharomyces cerevisiae both at the level of homology and synteny (conservation of gene order). Thus, it became possible to reinvestigate the S. cerevisiae genome in the syntenic regions leading to an improved annotation.     

The mbk-2 kinase is required for inactivation of MEI-1/katanin in the one-cell Caenorhabditis elegans embryo

The Caenorhabditis elegans early embryo is widely used to study the regulation of microtubule-related processes. In a screen for mutants affecting the first cell division, we isolated a temperature-sensitive mutation affecting pronuclear migration and spindle positioning, phenotypes typically linked to microtubule or centrosome defects. In the mutant, microtubules are shorter and chromosome segregation is impaired, while centrosome organization appears normal. The mutation corresponds to a strong loss of function in mbk-2, a conserved serine/threonine kinase. The microtubule-related defects are due to the postmeiotic persistence of MEI-1, a homologue of the microtubule-severing protein katanin. In addition, P-granule distribution is abnormal in mbk-2 mutants, consistent with genetic evidence that mbk-2 has other functions and with the requirement of mbk-2 activity at the one-cell stage. We propose that mbk-2 potentiates the degradation of MEI-1 and other proteins, possibly via direct phosphorylation.