Search results for "ORFS"
showing 10 items of 26 documents
The IStron CdISt1 of Clostridium difficile: molecular symbiosis of a group I intron and an insertion element
2003
Abstract The IStron CdISt1 was first discovered as an insertion into the tcdA gene of the clinical isolate C34. It combines structural and functional properties of a group I intron at its 5′-end with those of an insertion element at its 3′-end. Up to date four different types could be found, mainly differing in their IS-element portions. Contrasting classical group I introns, CdISt1 is always integrated in ORFs encoding bacterial protein. In case CdISt1 had only the IS-element function such insertion would inactivate the protein encoded by the host gene. It is only due to the self-splicing activity of the group I intron parts that CdISt1 integration does not abolish protein function. Both e…
A chimeric ribozyme in Clostridium difficile combines features of group I introns and insertion elements
2002
CdlSt1, a DNA insertion of 1975 bp, was identified within tcdA-C34, the enterotoxin gene of the Clostridium difficile isolate C34. Located in the catalytic domain A1-C34, Cd/St1 combines features of two genetic elements. Within the first 434 nt structures characteristic for group I introns were found; encoding the two transposase-like proteins tlpA and tlpB nucleotides 435-1975 represent the remainder of a IS605-like insertion element. We show that the entire CdlSt1 is accurately spliced from tcdA-C34 primary transcripts and that purified TcdA-C34 toxin is of regular size and catalytic activity. A search for CdlSt1-related sequences demonstrates that the element is widespread in toxinogenic…
Transcriptional and Structural Study of a Region of Two Convergent Overlapping Yeast Genes
1999
The exceptionally close packing of many yeast genes and other chromosomal elements raises the question of how those elements are functionally insulated. All published work shows that natural insulators are very effective, but transcriptional interference (TI) occurs if they are mutated or if their natural context is altered. Mechanisms to avoid TI are poorly understood, but are thought to involve an interplay of cis sequences and trans factors in a chromatin context. We have studied the case of two convergent closely packed ORFs (56 bp of separation) in chromosome IX of Saccharomyces cerevisiae. mRNAs from POT1 and YIL161w overlap by up to 115 nt. Convergent transcription causes a small but…
Isolation of a putative prolyl-tRNA synthetase (CaPRS) gene fromCandida albicans
1997
We have isolated a 4·0-kb fragment from a genomic library of Candida albicans which contained two open reading frames (ORFs). One of them is homologous to a prolyl-tRNA synthetase that catalyses the charging of a specific tRNA by proline (CaPRS). A deduced sequence of 575 amino acids representing a polypeptide of 66·2 kDa was determined. A FASTA search indicated that the CaPRSp had an overall similarity of 54·4% with the product of a Saccharomyces cerevisiae ORF (YER087) and 43·8% with the prolyl-tRNA synthetase of Escherichia coli (COLIPRO). Consensus Class II aminoacyl-tRNA synthetase sequences were identified by the PROSITE program. CaPRS was localized to chromosome R of the C. albicans …
The Nucleotide Sequence of a 39 kb Segment of Yeast Chromosome IV: 12 New Open Reading Frames, Nine Known Genes and One Gene for Gly-tRNA
1997
The complete nucleotide sequence of a 39 090 bp segment from the left arm of yeast chromosome IV was determined. Twenty-one open reading frames (ORFs) longer than 100 amino acids and a Gly-tRNA gene were discovered. Nine of the 21 ORFs (D0892, D1022, D1037, D1045, D1057, D1204, D1209, D1214, D1219) correspond to the previously sequenced Saccharomyces cerevisiae genes for the NAD-dependent glutamate dehydrogenase (GDH), the secretory component (SHR3), the GABA transport protein (UGA4), the high mobility group-like protein (NHP2), the hydroxymethylbilane synthase (HEM3), the methylated DNA protein-cysteine S-methyltransferase (MGT1), a putative sugar transport protein, the Shm1 protein (SHM1)…
Paaudžu problēmas Gētes jaunā Vērtera ciešanās un Plencdorfa Jaunā Vērtera jaunās ciešanas
2018
Maģistra darba tēma ir paaudžu problēmas Johana Volfganga fon Gētes romānā ''Jaunā Vertera ciešanas'' un Ulriha Plencdorfa ''Jaunā V. jaunās ciešanas'', pamatojoties uz šo divu darbu salīdzinājumu. Maģistra darba pirmajā daļā ir apskatītas Gētes un Plencdorfa biogrāfijas, lai saprastu, kas stāv aiz šiem bestselleriem. Tālāk abi autori tiek izskatīti kā viņu laika pārstāvji, proti, Gēte kā 18. gadsimta pārstāvis un Plencdorfs kā 20. gadsimta pārstāvis. Analizējot šo tēmu, atklājas, ka abas grāmatas bija ļoti populāras lasītāju vidū, taču valdības un tās pārstāvju viedoklis nebija pozitīvs. Darba otrajā daļā ir apskatīti vēsturiski notikumi Gētes dzīves laikā un pirms grāmatas sastādīšanas, t…
Direct sequencing of human gut virome fractions obtained by flow cytometry
2015
The sequence assembly of the human gut virome encounters several difficulties. A high proportion of human and bacterial matches is detected in purified viral samples. Viral DNA extraction results in a low DNA concentration, which does not reach the minimal limit required for sequencing library preparation. Therefore, the viromes are usually enriched by whole genome amplification, which is, however, prone to the development of chimeras and amplification bias. In addition, as there is a very wide diversity of gut viral species, very extensive sequencing efforts must be made for the assembling of whole viral genomes. We present an approach to improve human gut virome assembly by employing a mo…
ICTV Virus Taxonomy Profile: Polycipiviridae
2019
Polycipiviridae is a family of picorna-like viruses with non-segmented, linear, positive-sense RNA genomes of approximately 10–12 kb. Unusually for viruses within the order Picornavirales, their genomes are polycistronic, with four (or more) consecutive 5′-proximal open reading frames (ORFs) encoding structural (and possibly other) proteins and a long 3′ ORF encoding the replication polyprotein. Members of species within the family have all been detected in ants or via arthropod transcriptomic datasets. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the Polycipiviridae, which is available at www.ictv.global/report/polycipiviridae.
FEDRO: a software tool for the automatic discovery of candidate ORFs in plants with c →u RNA editing
2019
RNA editing is an important mechanism for gene expression in plants organelles. It alters the direct transfer of genetic information from DNA to proteins, due to the introduction of differences between RNAs and the corresponding coding DNA sequences. Software tools successful for the search of genes in other organisms not always are able to correctly perform this task in plants organellar genomes. Moreover, the available software tools predicting RNA editing events utilise algorithms that do not account for events which may generate a novel start codon. We present Fedro, a Java software tool implementing a novel strategy to generate candidate Open Reading Frames (ORFs) resulting from Cytidi…
A DNA region ofTorulaspora delbrueckii containing theHIS3 gene: sequence, gene order and evolution
2003
We cloned a genomic DNA fragment of the yeast Torulaspora delbrueckii by complementation of a Saccharomyces cerevisiae his3 mutant strain. DNA sequence analysis revealed that the fragment contained two complete ORFs, which share a high similarity with S. cerevisiae His3p and Mrp51p, respectively. The cloned TdHIS3 gene fully complemented the his3 mutation of S. cerevisiae, confirming that it encodes for the imidazoleglycerol-phosphate dehydrate of T. delbrueckii. Two additional ORFs, with a high homology to S. cerevisiae PET56 and DED1 genes, were mapped upstream and downstream from TdHIS3 and TdMRP51, respectively. This genetic organization is analogous to that previously found in Saccharo…