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At least 343 records · Page 19Linked to original sources

Comparative analysis of mouse NotI linking clones with mouse and human genomic sequences and transcripts.

NotI cleavage sites are frequently associated with CpG islands that identify the 5' regulatory sites of functional genes in the genome. Therefore we analyzed a sample of 22 NotI linking clones prepared from mouse brain DNA, to determine whether these mouse NotI site associated clones could be used for comparative analysis of mouse and human genomes by cross-reaction with both mouse and human genomic DNA and RNA in Southern and Northern hybridization. We further examined whether we could establish the identity of these clones with known genes by comparing the nucleotide sequences surrounding the NotI site with the GenBank database. We observed that 70% of the clones cross-hybridized with human DNA and that 4 of 11 tested clones (36%) detected a transcript in human HeLa cells RNA whereas 73% clones (8/11) detected transcripts in mouse RNAs from one or more organs. Single pass sequence analysis was successful on 16 of 19 clones. The GC content in these sequence was very high (48.8% to 73.8%) suggesting that 12 of 16 sequenced clones contained a CpG island. Three out of 19 clones showed significant similarity with previously analyzed mouse gene sequences in GenBank, including the mouse rRNA gene family, cathepsin and the scip POU-domain genes. In addition, two sequences showed significant similarity to the human and rabbit protein phosphatase 2A-beta subunit and the human transforming growth factor-beta. Thus, 5 of 16 clones showed homology with identified genes. These results and the recent work of using RLGS methods for genetic mapping indicate that NotI linking clones can be used to efficiently cross reference a comparative analysis of the mouse and human genomic maps.

Animals↗

Genetic diversity of ospC in a local population of Borrelia burgdorferi sensu stricto.

The outer surface protein, OspC, is highly variable in Borrelia burgdorferi sensu stricto, the agent of Lyme disease. We have shown that even within a single population OspC is highly variable. The variation of ospA and ospC in the 40 infected deer ticks collected from a single site on Shelter Island, New York, was determined using PCR-SSCP. There is very strong apparent linkage disequilibrium between ospA and ospC alleles, even though they are located on separate plasmids. Thirteen discernible SSCP mobility classes for ospC were identified and the DNA sequence for each was determined. These sequences, combined with 40 GenBank sequences, allow us to define 19 major ospC groups. Sequences within a major ospC group are, on average, <1% different from each other, while sequences between major ospC groups are, on average, approximately 20% different. The tick sample contains 11 major ospC groups, GenBank contains 16 groups, with 8 groups found in both samples. Thus, the ospC variation within a local population is almost as great as the variation of a similar-sized sample of the entire species. The Ewens-Watterson-Slatkin test of allele frequency showed significant deviation from the neutral expectation, indicating balancing selection for these major ospC groups. The variation represented by major ospC groups needs to be considered if the OspC protein is to be used as a serodiagnostic antigen or a vaccine.

Alleles↗

Molecular cloning of eukaryotic glycoprotein and glycolipid glycosyltransferases: a survey.

The rapidity with which molecular sequence data are gathered continues to grow. The result is that, for many workers, it is increasingly difficult to keep abreast of the current state of play of molecular cloning, even for those genes that encode proteins of special interest. The clear success of the various worldwide genome projects has made this even more apparent, and by the end of 1996 the complete determination of the nucleotide sequences of the genomes of two eukaryotes, Saccharomyces cerevisiae and Caenorhabditis elegans, will have either been completed or will be nearing completion. This article is an attempt to provide, in an easily accessible format, a compilation of genes and cDNAs that have been sequenced and deposited in GenBank that encode transferase enzymes involved in eukaryotic glycoprotein or glycolipid biosynthesis. The full sequence information can be easily retrieved from a databank, e.g. GenBank, using the relevant accession number(s).

Animals↗

The development of a high-density canine microarray.

DNA microarrays can give global transcriptional views of cellular responses to disease, development, nutrition, and other biological states. They can be used to elucidate biological networks, develop diagnostics, and identify genetic targets and molecular mechanisms. The technology is widely used and can be a valuable complement to more "disease-centric" focused arrays. For these reasons, Nestlé designed a custom canine Affymetrix microarray representing transcripts from multiple tissues for use in areas where a more focused microarray had not already been developed. Sufficient numbers of sequences representing messenger RNAs (mRNAs) or expressed sequence tags (ESTs) is integral for the design of a global microarray chip. This chip was designed using public domain sequences (GenBank) and sequences from a proprietary canine EST database. In order to enrich the chip with annotated transcripts, both of these sequence sets were BLASTed against the nonredundant protein database. The sequences on the microarray were isolated from more than 48 different tissues. The final compliment of sequences had sequences unique to GenBank (3160), unique to the proprietary EST database (17,620), and present in both sources (1996). In comparison with human sequences (RefSeq), 74% of the canine sequences matched a human sequence.

Animals↗

Comparison of Al-induced gene expression in sensitive and tolerant soybean cultivars.

In order to identify genes involved in soybean resistance to aluminium (Al) stress differential gene expression patterns of Al-stressed and non-stressed tolerant and sensitive soybean cultivars were compared. Out of eight described genes, potentially related to mechanisms of aluminium stress, only phosphoenolpyruvate carboxylase (PEPC) revealed enhanced expression in roots of tolerant as compared to sensitive soybean cultivars under stress conditions. Additionally, two novel full-length cDNA sequences, homologous to translationally controlled tumour proteins (TCTP, clone 58, GenBank accession number AF421558) and inosine-5'-monophosphate dehydrogenases (IMPDH, clone 633, GenBank accession number AF421559) with enhanced expression of the corresponding genes only in roots of Al-tolerant soybean cultivar under stress conditions were isolated and characterized. For functional analysis full-length cDNA 633 was transferred in Arabidopsis thaliana. Only 6% of the seedlings from the wild type survived Al stress, whereas 86% of transgenics were vital demonstrating superiority in stress protection. Compared with the wild type, transgenic plants showed diminished Al penetration into the roots after the stress treatment especially in the division and elongation zones of the roots. Formation of numerous lateral roots in transgenic plants with low elicited callose accumulation under stress conditions indicated ability of the IMPDH homologue to mediate aluminium tolerance in transgenic plants. Possible functional activities of Al up-regulated genes in resistance mechanisms are discussed.

Aluminum↗

The sequence asymmetry of the Escherichia coli chromosome appears to be independent of strand or function and may be evolutionarily conserved.

I have examined potential determinants of the asymmetric distribution of nucleotide sequences in the genome of Escherichia coli as cataloged in GenBank release 44. I have used the frequency of occurrence of all possible tetranucleotides in a given sequence catalog or derivative as a comparative measure of asymmetry. The GenBank-cataloged strand and its complement show statistically similar (not complementary) distributions. The distribution is statistically similar in comparisons between the protein coding subset and the total genome, the coding subset and selected non-coding genes, the coding subset and the remainder of the DNA, and the coding subset and stable RNA sequences. I have compared the distribution in the genome of E. coli with the distributions found in the cataloged genomes of Salmonella typhimurium, Bacillus subtilis, and of coliphages lambda and T7. The distribution summed in both strands of the cataloged DNA differs statistically only in comparisons with lytic bacteriophage T7 because only the two strands of T7 show statistically dissimilar distributions. Despite similarities in tetranucleotide distribution, the pattern of codon complementarity in B. subtilis is different than that documented for E. coli. Thus, sequence asymmetry does not seem related to specific DNA function or to documented similarities or differences in codon bias. The sequence asymmetry of the E. coli genome may thus reflect a hitherto unsuspected pattern impressed on both strands of DNA which is or can be packaged into bacterial genomes.

Bacillus subtilis↗

Predictive motifs derived from cytosine methyltransferases.

Thirteen bacterial DNA methyltransferases that catalyze the formation of 5-methylcytosine within specific DNA sequences possess related structures. Similar building blocks (motifs), containing invariant positions, can be found in the same order in all thirteen sequences. Five of these blocks are highly conserved while a further five contain weaker similarities. One block, which has the most invariant residues, contains the proline-cysteine dipeptide of the proposed catalytic site. A region in the second half of each sequence is unusually variable both in length and sequence composition. Those methyltransferases that exhibit significant homology in this region share common specificity in DNA recognition. The five highly conserved motifs can be used to discriminate the known 5-methylcytosine forming methyltransferases from all other methyltransferases of known sequence, and from all other identified proteins in the PIR, GenBank and EMBL databases. These five motifs occur in a mammalian methyltransferase responsible for the formation of 5-methylcytosine within CG dinucleotides. By searching the unidentified open reading frames present in the GenBank and EMBL databases, two potential 5-methylcytosine forming methyltransferases have been found.

Amino Acid Sequence↗

Neural network detects errors in the assignment of mRNA splice sites.

The use of databanks in genetic research assumes reliability of the information they contain. Currently, error-detection in the manually or electronically entered data contained in the nucleotide sequence databanks at EMBL, Heidelberg and GenBank at Los Alamos is limited. We have used a subset of sequences from these databanks to train neural networks to recognize pre-mRNA splicing signals in human genes. During the training on 33 human genes from the EMBL databank seven genes appeared to disturb the learning process. Subsequent investigation revealed discrepancies from the original published papers, for three genes. In four genes, we found wrongly assigned splicing frames of introns. We believe this to be a reflection of the fact that splicing frames cannot always be unambiguously assigned on the basis of experimental data. Thus incorrect assignment appear both due to mere typographical misprints as well as erroneous interpretation of experiments. Training on 241 human sequences from GenBank revealed nine new errors. We propose that such errors could be detected by computer algorithms designed to check the consistency of data prior to their incorporation in databanks.

Algorithms↗

Codon usage tabulated from the international DNA sequence databases.

The codon usage in individual protein genes has been calculated using the nucleotide sequence obtained from the GenBank Genetic Sequence Database. Sum of the codon use of each organism has been also calculated. The data files can be obtained from anonymous ftp sites of DDBJ, DISC and EBI. The list of codon usage of genes in organisms was made searchable by name of organism through a web site. The compilation has been synchronized with a major release of GenBank.

Base Sequence↗

FlyNets and GIF-DB, two internet databases for molecular interactions in Drosophila melanogaster.

GIF-DB and FlyNets are two WWW databases describing molecular (protein-DNA, protein-RNA and protein-protein) interactions occuring in the fly Drosophila melanogaster (http://gifts.univ-mrs.fr/GIFTS_home_page.html ). GIF-DB is a specialised database which focuses on molecular interactions involved in the process of embryonic pattern formation, whereas FlyNets is a new and more general database, the long-term goal of which is to report on any published molecular interaction occuring in the fly. The information content of both databases is distributed in specific lines arranged into an EMBL- (or GenBank-) like format. These databases achieve a high level of integration with other databases such as FlyBase, EMBL, GenBank and SWISS-PROT through numerous hyperlinks. In addition, we also describe SOS-DGDB, a new collection of annotated Drosophila gene sequences, in which binding sites for regulatory proteins are directly visible on the DNA primary sequence and hyperlinked both to GIF-DB and TRANSFAC database entries.

Animals↗

EpoDB: a prototype database for the analysis of genes expressed during vertebrate erythropoiesis.

EpoDB is a database of genes expressed in vertebrate red blood cells. It is also a prototype for the creation of cell and tissue-specific databases from multiple external sources. The information in EpoDB obtained from GenBank, SWISS-PROT, Transfac, TRRD and GERD is curated to provide high quality data for sequence analysis aimed at understanding gene regulation during erythropoiesis. New protocols have been developed for data integration and updating entries. Using a BLAST-based algorithm, we have grouped GenBank entries representing the same gene together. This sequence similarity protocol was also used to identify new entries to be included in EpoDB. We have recently implemented our database in Sybase (relational tables) in addition to SICStus Prolog to provide us with greater flexibility in asking complex queries that utilize information from multiple sources. New additions to the public web site (http://www.cbil.upenn.edu/epodb) for accessing EpoDB are the ability to retrieve groups of entries representing different variants of the same gene and to retrieve gene expression data. The BLAST query has been enhanced by incorporating BLASTView, an interactive and graphical display of BLAST results. We have also enhanced the queries for retrieving sequence from specified genes by the addition of MEME, a motif discovery tool, to the integrated analysis tools which include CLUSTALW and TESS.

Animals↗

Plant cis-acting regulatory DNA elements (PLACE) database: 1999.

PLACE (http://www.dna.affrc.go.jp/htdocs/PLACE/) is a database of nucleotide sequence motifs found in plant cis-acting regulatory DNA elements. Motifs were extracted from previously published reports on genes in vascular plants. In addition to the motifs originally reported, their variations in other genes or in other plant species in later reports are also compiled. Documents for each motif in the PLACE database contains, in addition to a motif sequence, a brief definition and description of each motif, and relevant literature with PubMed ID numbers and GenBank accession numbers where available. Users can search their query sequences for cis-elements using the Signal Scan program at our web site. The results will be reported in one of the three forms. Clicking the PLACE accession numbers in the result report will open the pertinent motif document. Clicking the PubMed or GenBank accession number in the document will allow users to access to these databases, and to read the of the literature or the annotation in the DNA database. This report summarizes the present status of this database and available tools.

Arabidopsis↗

Grasping at molecular interactions and genetic networks in Drosophila melanogaster using FlyNets, an Internet database.

FlyNets (http://gifts.univ-mrs.fr/FlyNets/FlyNets_home_page.++ +html) is a WWW database describing molecular interactions (protein-DNA, protein-RNA and protein-protein) in the fly Drosophila melanogaster. It is composed of two parts, as follows. (i) FlyNets-base is a specialized database which focuses on molecular interactions involved in Drosophila development. The information content of FlyNets-base is distributed among several specific lines arranged according to a GenBank-like format and grouped into five thematic zones to improve human readability. The FlyNets database achieves a high level of integration with other databases such as FlyBase, EMBL, GenBank and SWISS-PROT through numerous hyperlinks. (ii) FlyNets-list is a very simple and more general databank, the long-term goal of which is to report on any published molecular interaction occuring in the fly, giving direct web access to corresponding s in Medline and in FlyBase. In the context of genome projects, databases describing molecular interactions and genetic networks will provide a link at the functional level between the genome, the proteome and the transcriptome worlds of different organisms. Interaction databases therefore aim at describing the contents, structure, function and behaviour of what we herein define as the interactome world.

Animals↗

Caenorhabditis elegans mRNAs that encode a protein similar to ADARs derive from an operon containing six genes.

The Caenorhabditis elegans T20H4.4 open reading frame (GenBank accession no. U00037) predicted by Genefinder encodes a 367 amino acid protein that is 32-35% identical to the C-terminal domain of adenosine deaminases that act on RNA. We show that T20H4.4 cDNAs (GenBank accession no. AF051275) encode a larger 495 amino acid protein that is extended at its N-terminus to include a single double-stranded RNA-binding motif, and that T20H4.4 occupies the second position in a six-gene operon (5'-T20H4.5, T20H4.4, R151.8A, R151.8B, R151.7, R151.6-3'). Ten different spliced-leader (SL) sequences were found attached to T20H4.4 mRNAs, including SL1, SL2 and eight SL2-like leaders that include two new variants. Characterization of cDNAs derived from all six genes confirmed the essential features of C.elegans operons: intercistronic distances in the range of 104-257 nt between the upstream polyadenylation sites and the downstream trans -splice sites; SL2, or SL2-like leaders, attached to the downstream mRNAs. Polycistronic mRNA fragments revealed a 5'-untranslated region (5'-UTR) >705 nt. The 5'-UTR is removed in mature mRNAs from the first gene (T20H4.5) and replaced primarily by SL1, and to a lesser extent by SL2. Our study provides new information regarding operons and how they are processed.

5' Untranslated Regions↗

The distribution of RNA motifs in natural sequences.

Functional analysis of genome sequences has largely ignored RNA genes and their structures. We introduce here the notion of 'ribonomics' to describe the search for the distribution of and eventually the determination of the physiological roles of these RNA structures found in the sequence databases. The utility of this approach is illustrated here by the identification in the GenBank database of RNA motifs having known binding or chemical activity. The frequency of these motifs indicates that most have originated from evolutionary drift and are selectively neutral. On the other hand, their distribution among species and their location within genes suggest that the destiny of these motifs may be more elaborate. For example, the hammerhead motif has a skewed organismal presence, is phylogenetically stable and recent work on a schistosome version confirms its in vivo biological activity. The under-representation of the valine-binding motif and the Rev-binding element in GenBank hints at a detrimental effect on cell growth or viability. Data on the presence and the location of these motifs may provide critical guidance in the design of experiments directed towards the understanding and the manipulation of RNA complexes and activities in vivo.

Adenosine Triphosphate↗

Database resources of the National Center for Biotechnology Information.

In addition to maintaining the GenBank(R) nucleic acid sequence database, the National Center for Biotechnology Information (NCBI) provides data analysis and retrieval and resources that operate on the data in GenBank and a variety of other biological data made available through NCBI's Web site. NCBI data retrieval resources include Entrez, PubMed, LocusLink and the Taxonomy Browser. Data analysis resources include BLAST, Electronic PCR, OrfFinder, RefSeq, UniGene, Database of Single Nucleotide Polymorphisms (dbSNP), Human Genome Sequencing pages, GeneMap'99, Davis Human-Mouse Homology Map, Cancer Chromosome Aberration Project (CCAP) pages, Entrez Genomes, Clusters of Orthologous Groups (COGs) database, Retroviral Genotyping Tools, Cancer Genome Anatomy Project (CGAP) pages, SAGEmap, Online Mendelian Inheritance in Man (OMIM) and the Molecular Modeling Database (MMDB). Augmenting many of the Web applications are custom implementations of the BLAST program optimized to search specialized data sets. All of the resources can be accessed through the NCBI home page at: http://www.ncbi.nlm.nih. gov

Animals↗

The IDB and IEDB: intron sequence and evolution databases.

A non-redundant database of nuclear, protein-encoding, genomic DNA sequences highlighting nuclear pre-mRNA introns was constructed using information contained in the SWISS-PROT and GenBank sequence databases. This Intron DataBase (IDB) contains information about (i) introns (including nucleotide sequence, location, phase, length, GC content and consensus-sequence rule violations), (ii) exons (including nucleo-tide sequence, length and GC content), (iii) protein coding regions (including amino acid sequence and length), and (iv) descriptive information about the source gene and organism (including gene designations and species taxonomy). The Intron Evolution DataBase (IEDB) provides a statistical analysis of the exon and intron sequences catalogued in IDB as well as data concerning intron penetration (relative number of coding regions with introns), density (number of introns per kb of total coding sequence DNA), distribution, and consensus sequences for each species present in IDB. This supplement is provided to furnish insights into the phylogenetic distribution and evolution of introns. Both databases are extensively cross-referenced to the SWISS-PROT and GenBank databases. IDB currently contains information on over 63 000 genes and 154 000 introns; IEDB summarizes information on over 2800 species. IDB and IEDB will be updated twice a year and are available via the internet (http://nutmeg.bio.indiana. edu/intron/index.html ).

Base Sequence↗

EID: the Exon-Intron Database-an exhaustive database of protein-coding intron-containing genes.

To aid studies of molecular evolution and to assist in gene prediction research, we have constructed an Exon-Intron Database (EID) in FASTA format. Currently, the database is derived from GenBank release 112, and it contains 51 289 protein-coding genes (287 209 exons) that harbor introns, along with extensive descriptions of each gene and its DNA and protein sequences, as well as splice motif information. There is 17% redundancy inherited from GenBank-a purge at the 99% identity level reduced the database to 42 460 genes (243 589 exons). We have created subdatabases of genes whose intron positions have been experimentally determined. One such database, constructed by comparing genomic and mRNA sequences, contains 11 242 genes (62 474 exons). A larger database of 22 196 genes (105 595 exons) was constructed by selecting on keywords to eliminate computer-predicted genes. By examining the two nucleotides adjacent to the intron boundary, we infer that there is a 2% rate of errors or other deviations from the standard GTellipsisAG motif in nuclear genes. This criterion can be used to eliminate 4921 genes from the overall database. Various tools are provided to enable generation of user-specific subsets of the EID. The EID distribution can be obtained from http://mcb.harvard.edu/gilbert/EID

Base Sequence↗