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Putative Homologues (putative + homologue)
Selected AbstractsTranscriptome analysis of bud burst in sessile oak (Quercus petraea)NEW PHYTOLOGIST, Issue 4 2006Jérémy Derory Summary ,,Expression patterns of hundreds of transcripts in apical buds were monitored during bud flushing in sessile oak (Quercus petraea), in order to identify genes differentially expressed between the quiescent and active stage of bud development. ,,Different transcriptomic techniques combining the construction of suppression subtractive hybridization (SSH) libraries and the monitoring of gene expression using macroarray and real-time reverse transcriptase polymerase chain reaction (RT-PCR) were performed to dissect bud burst, with a special emphasis on the onset of the process. ,,We generated 801 expressed sequence tags (ESTs) derived from six developmental stages of bud burst. Macroarray experiment revealed a total of 233 unique transcripts exhibiting differential expression during the process, and a putative function was assigned to 65% of them. Cell rescue/defense-, metabolism-, protein synthesis-, cell cycle- and transcription-related transcripts were among the most regulated genes. Macroarray and real-time RT-PCR showed that several genes exhibited contrasted expressions between quiescent and swelling buds, such as a putative homologue of the transcription factor DAG2 (Dof Affecting Germination 2), previously reported to be involved in the control of seed germination in Arabidopsis thaliana. ,,These differentially expressed genes constitute relevant candidates for signaling pathway of bud burst in trees. [source] Cloning and expression of a geranylgeranyl diphosphate synthase gene: insights into the synthesis of termite defence secretionINSECT MOLECULAR BIOLOGY, Issue 1 2007Masaru Hojo Abstract In Nasutitermes takasagoensis, a termite in which soldiers perform specialized chemical defence, Nts19-1 gene is highly expressed exclusively in soldier head. In this study, two types of transcripts for this gene were obtained, and the full-length cDNAs were determined by rapid amplification of cDNA ends (RACE). These transcripts were putative homologues of the geranylgeranyl diphosphate (GGPP) synthase gene, involved in the condensation of dimethylallyl diphosphate with isopentenyl diphosphate in the isoprenoid biosynthetic pathway. The genes were thus termed NtGGPPS1. GGPP is a precursor of diterpenes in plants. In situ hybridization localized NtGGPPS1 expression to the epidermal secretory cells of the frontal gland reservoir where many kinds of diterpenes are produced, suggesting that NtGGPPS1 is involved in the biosynthesis of defence secretion. [source] Accumulation of Defence Response-related and Unique Expressed Sequence Tags during the Incompatible Interaction in the Oryza sativa,Magnaporthe oryzae PathosystemJOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2009Rekha Dixit Abstract Resistance gene-dependent accumulation of expressed sequence tags (ESTs) was studied in a blast resistant, Oryza sativa ssp. indica cv. Tetep after challenge inoculation with an incompatible race of Magnaporthe oryzae. The nucleotide sequence of 287 randomly selected cDNA clones from the rice cDNA library constructed from the RNA isolated after challenge inoculation of the host was obtained and submitted in NCBI Genbank (Accession Nos. DN475717,DN475431). Of these, 184 (63%) ESTs were highly representative of the rice transcriptomes. A set of 178 unique transcripts was identified after assembly of 287 ESTs into unigenes. These unigenes were categorized into 17 functional groups. Analysis of this EST library illustrated a broad functional representation. Twenty-one unigenes were identified as putative homologues of the genes that were up regulated during host,pathogen interaction. Similarity search of 178 unigenes with NCBI database of 14 plants unigenes showed similarity ranging from 29,100%. The unigenes obtained in this study were physically located on the pseudomolecules of rice genome. This information can be used for determining the arrays of genes being expressed during Oryza sativa,M. oryzae interactions, which will be helpful in understanding the molecular basis of disease resistance. [source] Genomic tools and cDNA derived markers for butterfliesMOLECULAR ECOLOGY, Issue 9 2005ALEXIE PAPANICOLAOU Abstract The Lepidoptera have long been used as examples in the study of evolution, but some questions remain difficult to resolve due to a lack of molecular genetic data. However, as technology improves, genomic tools are becoming increasingly available to tackle unanswered evolutionary questions. Here we have used expressed sequence tags (ESTs) to develop genetic markers for two Müllerian mimic species, Heliconius melpomene and Heliconius erato. In total 1363 ESTs were generated, representing 330 gene objects in H. melpomene and 431 in H. erato. User-friendly bioinformatic tools were used to construct a nonredundant database of these putative genes (available at http://www.heliconius.org), and annotate them with blast similarity searches, InterPro matches and Gene Ontology terms. This database will be continually updated with EST sequences for the Papilionideae as they become publicly available, providing a tool for gene finding in the butterflies. Alignments of the Heliconius sequences with putative homologues derived from Bombyx mori or other public data sets were used to identify conserved PCR priming sites, and develop 55 markers that can be amplified from genomic DNA in both H. erato and H. melpomene. These markers will be used for comparative linkage mapping in Heliconius and will have applications in other phylogenetic and genomic studies in the Lepidoptera. [source] The galactokinase of Hypocrea jecorina is essential for cellulase induction by lactose but dispensable for growth on d -galactoseMOLECULAR MICROBIOLOGY, Issue 4 2004Bernhard Seiboth Summary Lactose is the only soluble carbon source which can be used economically for the production of cellulases or heterologous proteins under cellulase expression signals by Hypocrea jecorina (=Trichoderma reesei). Towards an understanding of lactose metabolism and its role in cellulase formation, we have cloned and characterized the gal1 (galactokinase) gene of H. jecorina, which catalyses the first step in d -galactose catabolism. It exhibits a calculated Mr of 57 kDa, and shows moderate identity (about 40%) to its putative homologues of Saccharomyces cerevisiae and Kluyveromyces lactis. Gal1 is a member of the GHMP family, shows conservation of a Gly/Ser rich region involved in ATP binding and of amino acids (Arg 51, Glu 57, Asp 60, Asp 214, Tyr 270) responsible for galactose binding. A single transcript was formed constitutively during the rapid growth phase on all carbon sources investigated and accumulated to about twice this level during growth on d -galactose, l -arabinose and their corresponding polyols. Deletion of gal1 reduces growth on d -galactose but does only slightly affect growth on lactose. This is the result of the operation of a second pathway for d -galactose catabolism, which involves galactitol as an intermediate, and whose transient concentration is strongly enhanced in the delta- gal1 strain. In this pathway, galactitol is catabolised by the lad1 -encoded l -arabinitol-4-dehydrogenase, because a gal1/lad1 double delta-mutant failed to grow on d -galactose. In the delta- gal1 strain, induction of the Leloir pathway gene gal7 (encoding galactose-1-phosphate uridylyltransferase) by d -galactose, but not by l -arabinose, is impaired. Induction of cellulase gene expression by lactose is also impaired in a gal1 deleted strain, whereas their induction by sophorose (the putative cellulose-derived inducer) was shown to be normal, thus demonstrating that galactokinase is a key enzyme for cellulase induction during growth on lactose, and that induction by lactose and sophorose involves different mechanisms. [source] Comparison of the sequences of the Aspergillus nidulans hxB and Drosophila melanogaster ma-l genes with nifS from Azotobacter vinelandii suggests a mechanism for the insertion of the terminal sulphur atom in the molybdopterin cofactorMOLECULAR MICROBIOLOGY, Issue 1 2000Laïla Amrani The molybdopterin cofactor (MoCF) is required for the activity of a variety of oxidoreductases. The xanthine oxidase class of molybdoenzymes requires the MoCF to have a terminal, cyanolysable sulphur ligand. In the sulphite oxidase/nitrate reductase class, an oxygen is present in the same position. Mutations in both the ma-l gene of Drosophila melanogaster and the hxB gene of Aspergillus nidulans result in loss of activities of all molybdoenzymes that necessitate a cyanolysable sulphur in the active centre. The ma-l and hxB genes encode highly similar proteins containing domains common to pyridoxal phosphate-dependent cysteine transulphurases, including the cofactor binding site and a conserved cysteine, which is the putative sulphur donor. Key similarities were found with NifS, the enzyme involved in the generation of the iron,sulphur centres in nitrogenase. These similarities suggest an analogous mechanism for the generation of the terminal molybdenum-bound sulphur ligand. We have identified putative homologues of these genes in a variety of organisms, including humans. The human homologue is located in chromosome 18.q12. [source] cDNA-AFLP reveals genes differentially expressed during the hypersensitive response of cassavaMOLECULAR PLANT PATHOLOGY, Issue 2 2005BENJAMIN P. KEMP SUMMARY The tropical staple cassava is subject to several major diseases, such as cassava bacterial blight, caused by Xanthomonas axonopodis pv. manihotis. Disease-resistant genotypes afford the only practical solution, yet despite the global importance of this crop, little is known about its defence mechanisms. cDNA-AFLP was used to isolate cassava genes differentially expressed during the hypersensitive reaction (HR) of leaves in response to an incompatible Pseudomonas syringae pathovar. Seventy-eight transcript-derived fragments (TDFs) showing differential expression (c. 75% up-regulated, 25% down-regulated) were identified. Many encoded putative homologues of known defence-related genes involved in signalling (e.g. calcium transport and binding, ACC oxidases and a WRKY transcription factor), cell wall strengthening (e.g. cinnamoyl coenzyme A reductase and peroxidase), programmed cell death (e.g. proteases, 26S proteosome), antimicrobial activity (e.g. proteases and ,-1,3-glucanases) and the production of antimicrobial compounds (e.g. DAHP synthase and cytochrome P450s). Full-length cDNAs including a probable matrix metalloprotease and a WRKY transcription factor were isolated from six TDFs. RT-PCR or Northern blot analysis showed HR-induced TDFs were maximally expressed at 24 h, although some were produced by 6 h; some were induced, albeit more slowly, in response to wounding. This work begins to reveal potential defence-related genes of this understudied, major crop. [source] | ||||||||||