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The ori sequences of the mitochondrial genomes of 20 wild-type strains of Saccharomyces cerevisiae were compared with those of the previously studied strain A (de Zamaroczy et al., 1984). The seven canonical ori sequences of this strain appear to be present in all strains tested, but in most strains ori1 is replaced by an extensively rearranged ori1 1 sequence, and an additional ori sequence, ori8, is present between the oxi3 and the 15S RNA genes; one strain, B, lacks ori4. The location and orientation of ori sequences of three strains, B, C and K, were found to be the same as in strain A. The primary structures of four ori sequences from three different strains (ori1 of strain J69-1B, ori3 and ori5 of strain K, ori6 of strain D273-10B) were found to be identical with the corresponding ori sequences previously investigated. Hybridization experiments with different on probes indicated a conservation of ori2–ori7 sequences in all strains tested. The primary structure of a petite genome derived from strain B and carrying ori1 1 is reported and discussed.  相似文献   

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Nishizawa Y  Yabuki T  Fukuda E  Wakagi T 《FEBS letters》2005,579(11):2319-2322
A hyperthermophilic and aerobic crenarchaeon, Aeropyrum pernix K1, has two sets of genes possibly encoding 2-oxoacid:ferredoxin oxidoreductases. One is encoded in open reading frames (ORFs) ape2126 and ape2128, and the other in ORFs ape1473 and ape1472. The two sets of genes were expressed. The product enzymes, Ape2126/2128 and Ape1473/1472, showed optimal temperatures of 105 and over 110 degrees C, and optimal pHs of 8.5 and 9.0, respectively, using pyruvate as a substrate. Pyruvate, 2-oxobutyrate, and glyoxylate were the best substrates for both enzymes, and additionally Ape1473/1472 was able to act on 2-oxoglutarate, suggesting the enzyme operates in the TCA cycle.  相似文献   

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Accurate cDNA data is useful to validate gene structures in a genome. We sequenced 35 189 expressed sequence tags (ESTs) obtained from the highly destructive rice blast fungus, Magnaporthe grisea. Our custom-made computational programs mapped these ESTs on the M. grisea genome sequence, and reconstructed gene structures as well as protein-coding regions. As a result, we predicted 4480 protein-coding sequences, which were more accurate than ab initio predictions. Moreover, cross-species comparisons suggested that our predicted proteins were nearly complete. The cDNA clones obtained in this study will be important for further experimental studies. Our genome annotation is available at http://www.mg.dna.affrc.go.jp/.  相似文献   

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Phosphoethanolamine N-methyltransferase (PEAMT) is involved in choline biosynthesis in plants. The 5′ untranslated region (UTR) of several PEAMT genes was found to contain an upstream open reading frame (uORF). We generated transgenic Arabidopsis calli that expressed a chimeric gene constructed by fusing the 5′ UTR of the Arabidopsis PEAMT gene (AtNMT1) upstream of the β-glucuronidase gene. The AtNMT1 uORF was found to be involved in declining levels of the chimeric gene mRNA and repression of downstream β-glucuronidase gene translation in the calli when the cells were treated with choline. Further, we discuss the role of the uORF.  相似文献   

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Genes of the Schlafen family, first discovered in mouse, are expressed in hematopoietic cells and are involved in immune processes. Previous results showed that they are candidate genes for two major phenomena: meiotic drive and embryonic lethality (DDK syndrome). However, these genes remain poorly understood, mostly due to the limitations imposed by their similarity, close location and the potential functional redundancy of the gene family members.  相似文献   

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Onion can be used in experimental observation of mitotic cell division in plant science because its chromosome is large and easy to observe. However, molecular genetic studies are difficult in onion because of its large genome size, and only limited information of onion genes has been available to date. Here we cloned and characterized an onion homologue of mitotic RAD21 gene, AcRAD21-1, to develop a molecular marker of mitosis. The N-terminal, middle, and C-terminal regions of deduced AcRAD21-1 protein sequence were conserved with Arabidopsis SYN4/AtRAD21.3 and rice OsRAD21-1, whereas three characteristic types of repetitive motifs (Repeat-1, Repeat-2/2′, and Repeat-3) were observed between the conserved regions. Such inserted repetitive amino acid sequences enlarge the AcRAD21-1 protein into almost 200 kDa, which belongs to the largest class of plant proteins. Genomic organization of the AcRAD21-1 locus was also determined, and the possibility of tandem exon duplication in Repeat-2 was revealed. Subsequently, the polyclonal antiserum was raised against the N-terminal region of AcRAD21-1, and purified by affinity chromatography. Immunohistochemical analysis with the purified antibody successfully showed localization of AcRAD21-1 in onion mitosis, suggesting that it can be used as a molecular marker visualizing dynamic movement of cohesin.  相似文献   

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K. Hill  C. Boone  M. Goebl  R. Puccia  A. M. Sdicu    H. Bussey 《Genetics》1992,130(2):273-283
We have cloned, sequenced and disrupted the KRE2 gene of Saccharomyces cerevisiae, identified by killer-resistant mutants with a defective cell wall receptor for the toxin. The KRE2 gene is close to PHO8 on chromosome 4, and encodes a predicted 49-kD protein, Kre2p, that probably enters the secretory pathway. Haploid cells carrying a disruption of the KRE2 locus grow more slowly than wild-type cells at 30 degrees, and fail to grow at 37 degrees. At 30 degrees, kre2 mutants showed altered N-linked glycosylation of proteins, as the average size of N-linked outer chains was reduced. We identified two other genes, YUR1 on chromosome 10, and KTR1 on chromosome 15, whose predicted products share 36% identity with Kre2p over more than 300 amino acid residues. Yur1p has an N-terminal signal sequence like Kre2p, while Ktr1p has a predicted topology consistent with a type 2 membrane protein. In all cases the conserved regions of these proteins appear to be on the lumenal side of secretory compartments, suggesting related function. KRE2, KTR1 and YUR1 define a new yeast gene family.  相似文献   

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Estuarine tapertail anchovy (Coilia nasus, junior synonym C. ectenes) is a widely distributed and commercially important aquaculture species, although its growth in aquaculture settings is so slow as to pose a serious practical problem. In order to understand the molecular mechanisms of growth, we cloned the myostatin gene in C. nasus (CnMSTN) by homologous cloning methods. Its full-length cDNA is 2252 bp, with a 1125-bp open reading frame (ORF) that encodes a 374-amino acid protein. The CnMSTN protein is predicted to contain domains typical of MSTN, including a TGFb-propeptide domain and a TGFB domain. Gene expression patterns were detected by RT-qPCR. CnMSTN is expressed strongly in the muscle and brain, and comparatively lower in the gills, liver, spleen, intestine, trunk kidney and head kidney. The effects of stress on the muscle and brain MSTN levels were evaluated by RT-qPCR. CnMSTN in the muscle was positively regulated by loading and transport stress, but brain CnMSTN expression was not affected. We found NaCl could reduce the death rate caused by loading and transporting stress, and in this group, CnMSTN mRNA expression in the muscle revealed increased, but decreased in the brain. Further, in the fasting experiment, the CnMSTN mRNA revealed decrease in the muscle, on the contrary, it showed increase in the brain. Selection upon variants of the MSTN gene has shown great potential in breeding work for mammals, and our results provide the basic knowledge for breeding of C. nasus.  相似文献   

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Chromatin assembly factor I (CAF-I) is a three-subunit histone-binding complex conserved from the yeast Saccharomyces cerevisiae to humans. Yeast cells lacking CAF-I (cacΔ mutants) have defects in heterochromatic gene silencing. In this study, we showed that deletion of HIR genes, which regulate histone gene expression, synergistically reduced gene silencing at telomeres and at the HM loci in cacΔ mutants, although hirΔ mutants had no silencing defects when CAF-I was intact. Therefore, Hir proteins are required for an alternative silencing pathway that becomes important in the absence of CAF-I. Because Hir proteins regulate expression of histone genes, we tested the effects of histone gene deletion and overexpression on telomeric silencing and found that alterations in histone H3 and H4 levels or in core histone stoichiometry reduced silencing in cacΔ mutants but not in wild-type cells. We therefore propose that Hir proteins contribute to silencing indirectly via regulation of histone synthesis. However, deletion of combinations of CAC and HIR genes also affected the growth rate and in some cases caused partial temperature sensitivity, suggesting that global aspects of chromosome function may be affected by the loss of members of both gene families.  相似文献   

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We isolated a temperature-sensitive mutant, hrd4-1, deficient in ER-associated degradation (ERAD). The HRD4 gene was identical to NPL4, a gene previously implicated in nuclear transport. Using a diverse set of substrates and direct ubiquitination assays, our analysis revealed that HRD4/NPL4 is required for a poorly characterized step in ERAD after ubiquitination of target proteins but before their recognition by the 26S proteasome. Our data indicate that this lack of proteasomal processing of ubiquitinated proteins constitutes the primary defect in hrd4/npl4 mutant cells and explains the diverse set of hrd4/npl4 phenotypes. We also found that each member of the Cdc48p-Ufd1p-Npl4p complex is individually required for ERAD.  相似文献   

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The product of gene A of the small icosahedral DNA phage S13 has been found to be needed for single-stranded DNA synthesis in vivo in addition to its previously known role in progeny replicative-form DNA synthesis.  相似文献   

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Two Arthrobacter nicotinovorans molybdenum enzymes hydroxylate the pyridine ring of nicotine. Molybdopterin cytosine dinucleotide (MCD) was determined to be a cofactor of these enzymes. A mobA gene responsible for the formation of MCD could be identified and its function shown to be required for assembly of the heterotrimeric molybdenum enzymes.  相似文献   

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Ankyrin-G (AnkG) coordinates protein composition of diverse membrane domains, including epithelial lateral membranes and neuronal axon initial segments. However, how AnkG itself localizes to these membrane domains is not understood. We report that AnkG remains on the plasma membrane in Madin-Darby canine kidney (MDCK) cells grown in low calcium, although these cells lack apical-basal polarity and exhibit loss of plasma membrane association of AnkG partners, E-cadherin and β2-spectrin. We subsequently demonstrate using mutagenesis and mass spectrometry that AnkG is S-palmitoylated exclusively at Cys-70, which is located in a loop of the first ankyrin repeat and is conserved in the vertebrate ankyrin family. Moreover, C70A mutation abolishes membrane association of 190-kDa AnkG in MDCK cells grown in low calcium. C70A 190-kDa AnkG fails to restore biogenesis of epithelial lateral membranes in MDCK cells depleted of endogenous AnkG. In addition, C70A 270-kDa AnkG fails to cluster at the axon initial segment of AnkG-depleted cultured hippocampal neurons and fails to recruit neurofascin as well as voltage-gated sodium channels. These effects of C70A mutation combined with evidence for its S-palmitoylation are consistent with a requirement of palmitoylation for targeting and function of AnkG in membrane domain biogenesis at epithelial lateral membranes and neuronal axon initial segments.  相似文献   

19.
DYF-1 is a highly conserved protein essential for ciliogenesis in several model organisms. In Caenorhabditis elegans, DYF-1 serves as an essential activator for an anterograde motor OSM-3 of intraflagellar transport (IFT), the ciliogenesis-required motility that mediates the transport of flagellar precursors and removal of turnover products. In zebrafish and Tetrahymena DYF-1 influences the cilia tubulin posttranslational modification and may have more ubiquitous function in ciliogenesis than OSM-3. Here we address how DYF-1 biochemically interacts with the IFT machinery by using the model organism Chlamydomonas reinhardtii, in which the anterograde IFT does not depend on OSM-3. Our results show that this protein is a stoichiometric component of the IFT particle complex B and interacts directly with complex B subunit IFT46. In concurrence with the established IFT protein nomenclature, DYF-1 is also named IFT70 after the apparent size of the protein. IFT70/CrDYF-1 is essential for the function of IFT in building the flagellum because the flagella of IFT70/CrDYF-1–depleted cells were greatly shortened. Together, these results demonstrate that IFT70/CrDYF-1 is a canonical subunit of IFT particle complex B and strongly support the hypothesis that the IFT machinery has species- and tissue-specific variations with functional ramifications.  相似文献   

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The origin of novel protein-coding genes de novo was once considered so improbable as to be impossible. In less than a decade, and especially in the last five years, this view has been overturned by extensive evidence from diverse eukaryotic lineages. There is now evidence that this mechanism has contributed a significant number of genes to genomes of organisms as diverse as Saccharomyces, Drosophila, Plasmodium, Arabidopisis and human. From simple beginnings, these genes have in some instances acquired complex structure, regulated expression and important functional roles. New genes are often thought of as dispensable late additions; however, some recent de novo genes in human can play a role in disease. Rather than an extremely rare occurrence, it is now evident that there is a relatively constant trickle of proto-genes released into the testing ground of natural selection. It is currently unknown whether de novo genes arise primarily through an ‘RNA-first’ or ‘ORF-first’ pathway. Either way, evolutionary tinkering with this pool of genetic potential may have been a significant player in the origins of lineage-specific traits and adaptations.  相似文献   

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