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The International Gene Trap Consortium Website: a portal to all publicly available gene trap cell lines in mouse.

Gene trapping is a method of generating murine embryonic stem (ES) cell lines containing insertional mutations in known and novel genes. A number of international groups have used this approach to create sizeable public cell line repositories available to the scientific community for the generation of mutant mouse strains. The major gene trapping groups worldwide have recently joined together to centralize access to all publicly available gene trap lines by developing a user-oriented Website for the International Gene Trap Consortium (IGTC). This collaboration provides an impressive public informatics resource comprising approximately 45 000 well-characterized ES cell lines which currently represent approximately 40% of known mouse genes, all freely available for the creation of knockout mice on a non-collaborative basis. To standardize annotation and provide high confidence data for gene trap lines, a rigorous identification and annotation pipeline has been developed combining genomic localization and transcript alignment of gene trap sequence tags to identify trapped loci. This information is stored in a new bioinformatics database accessible through the IGTC Website interface. The IGTC Website (www.genetrap.org) allows users to browse and search the database for trapped genes, BLAST sequences against gene trap sequence tags, and view trapped genes within biological pathways. In addition, IGTC data have been integrated into major genome browsers and bioinformatics sites to provide users with outside portals for viewing this data. The development of the IGTC Website marks a major advance by providing the research community with the data and tools necessary to effectively use public gene trap resources for the large-scale characterization of mammalian gene function.

Animals↗

Predicted roles for hypothetical proteins in the low-temperature expressed proteome of the Antarctic archaeon Methanococcoides burtonii.

Using liquid chromatography-mass spectrometry, 528 proteins were identified that are expressed during growth at 4 degrees C in the cold adapted archaeon, Methanococcoides burtonii. Of those, 135 were annotated previously as unique or conserved hypothetical proteins. We have performed a comprehensive, integrated analysis of the latter proteins using threading, InterProScan, predicted subcellular localization and visualization of conserved gene context across multiple prokaryotic genomes. Functional information was obtained for 55 proteins, providing new insight into the physiology of M. burtonii. Many of the proteins were predicted to be involved in DNA/RNA binding or modification and cell signaling, suggesting a complex, uncharacterized regulatory network controlling cellular processes during growth at low-temperature. Novel enzymatic functions were predicted for several proteins, including a putative candidate gene for the posttranslational modification of the key methanogenesis enzyme coenzyme M methyl reductase. A bacterial-like CRISPR locus was identified as a strong candidate for archaeal-bacterial lateral gene transfer. Gene context analysis proved a valuable augmentation to the other predictive methods in several cases, by revealing conserved gene associations and annotations in other microbial genomes. Our results underscore the importance of addressing the "hypothetical protein problem" for a complete understanding of cell physiology.

Adaptation, Physiological↗

Trends between gene content and genome size in prokaryotic species with larger genomes.

Although the evolution process and ecological benefits of symbiotic species with small genomes are well understood, these issues remain poorly elucidated for free-living species with large genomes. We have compared 115 completed prokaryotic genomes by using the Clusters of Orthologous Groups database to determine whether there are changes with genome size in the proportion of the genome attributable to particular cellular processes, because this may reflect both cellular and ecological strategies associated with genome expansion. We found that large genomes are disproportionately enriched in regulation and secondary metabolism genes and depleted in protein translation, DNA replication, cell division, and nucleotide metabolism genes compared to medium- and small-sized genomes. Furthermore, large genomes do not accumulate noncoding DNA or hypothetical ORFs, because the portion of the genome devoted to these functions remained constant with genome size. Traits other than genome size or strain-specific processes are reflected by the dispersion around the mean for cell functions that showed no correlation with genome size. For example, Archaea had significantly more genes in energy production, coenzyme metabolism, and the poorly characterized category, and fewer in cell membrane biogenesis and carbohydrate metabolism than Bacteria. The trends we noted with genome size by using Clusters of Orthologous Groups were confirmed by our independent analysis with The Institute for Genomic Research's Comprehensive Microbial Resource and Kyoto Encyclopedia of Genes and Genomes' Orthology annotation databases. These trends suggest that larger genome-sized species may dominate in environments where resources are scarce but diverse and where there is little penalty for slow growth, such as soil.

Animals↗

Characterization of the mouse brain proteome using global proteomic analysis complemented with cysteinyl-peptide enrichment.

We report a global proteomic approach for analyzing brain tissue and for the first time a comprehensive characterization of the whole mouse brain proteome. Preparation of the whole brain sample incorporated a highly efficient cysteinyl-peptide enrichment (CPE) technique to complement a global enzymatic digestion method. Both the global and the cysteinyl-enriched peptide samples were analyzed by SCX fractionation coupled with reversed phase LC-MS/MS analysis. A total of 48,328 different peptides were confidently identified (>98% confidence level), covering 7792 nonredundant proteins ( approximately 34% of the predicted mouse proteome). A total of 1564 and 1859 proteins were identified exclusively from the cysteinyl-peptide and the global peptide samples, respectively, corresponding to 25% and 31% improvements in proteome coverage compared to analysis of only the global peptide or cysteinyl-peptide samples. The identified proteins provide a broad representation of the mouse proteome with little bias evident due to protein pI, molecular weight, and/or cellular localization. Approximately 26% of the identified proteins with gene ontology (GO) annotations were membrane proteins, with 1447 proteins predicted to have transmembrane domains, and many of the membrane proteins were found to be involved in transport and cell signaling. The MS/MS spectrum count information for the identified proteins was used to provide a measure of relative protein abundances. The mouse brain peptide/protein database generated from this study represents the most comprehensive proteome coverage for the mammalian brain to date, and the basis for future quantitative brain proteomic studies using mouse models. The proteomic approach presented here may have broad applications for rapid proteomic analyses of various mouse models of human brain diseases.

Animals↗

Prediction of the coding sequences of unidentified human genes. XXI. The complete sequences of 60 new cDNA clones from brain which code for large proteins.

As an extension of a sequencing project of human cDNA clones which encode large proteins of unidentified genes, we herein present the entire sequences of 60 cDNA clones for the genes named KIAA1879-KIAA1938. The cDNA clones were isolated from size-fractionated cDNA libraries derived from human fetal brain, adult whole brain and amygdala, and their protein-coding sequences were predicted. Thirty-seven cDNA clones entirely sequenced in this study were selected as cDNAs which have coding potentiality by in vitro transcription/translation experiments, and the remaining 23 cDNA clones were chosen by computer-assisted analysis of terminal sequences of cDNAs. The average sizes of the inserts and corresponding open reading frames of cDNA clones analyzed here were 4.5 kb and 2.2 kb (733 amino acid residues), respectively. Sequence analyses against the public databases enabled us to annotate the functions of the predicted products of the 25 genes; 84% of these predicted gene products (21 gene products) were classified into proteins related to cell signaling/communication, nucleic acid management, and cell structure/motility. In addition to the sequence information about these 60 genes, their expression profiles were also studied in some human tissues including brain regions by reverse transcription-coupled polymerase chain reaction, products of which were quantified by enzyme-linked immunosorbent assay.

Adult↗

FindTarget: software for subtractive genome analysis.

In silico subtractive/differential genome analysis is a powerful approach for identifying genus- or species-specific genes, or groups of genes that are responsible for a unique phenotype. By this method, one searches for genes present in one group of bacteria and absent in another group. A software package has been developed, named FindTarget, that has a user-friendly web interface to facilitate differential genome analysis. The user chooses the genomes to compare, the similarity criteria and the thresholds to decide if a gene has a counterpart in another genome. The searches are based on BLASTP comparisons of proteomes. FindTarget also includes access to sequences, coloured multiple alignments, phylogenetic trees of conserved proteins and links to public annotated databases which provide a means for validation of the results. To illustrate this approach, a FindTarget search for genes putatively involved in the specificity of cell envelope synthesis of Gram-negative bacteria is presented. The results show that most of the identified genes are clearly involved in cell wall processes, underlining the power of such an approach in general and that of FindTarget in particular.

Bacterial Proteins↗

Gene expression profiling of bone marrow stromal cells from juvenile, adult, aged and osteoporotic rats: with an emphasis on osteoporosis.

PURPOSE: Osteoporosis is a multi-factorial, age-related disease with a complex etiology and mode of regulation involving a large numbers of genes. To better understand the possible relationships among genes, we fingerprinted genes in a rat model induced by ovariectomy to determine differences among osteoporotic, non-osteoporotic, aged and juvenile rats. METHODS: We applied genome wide cDNA microarray technology to analyze genes expressed in bone marrow mesenchymal stromal cells (BMSC) and compared non-osteoporotic adult vs. osteoporotic, non-osteoporotic adult vs. aged, and non-osteoporotic adult vs. juvenile. Rigorous statistical analysis of functional annotation (EASE program) identified over-represented biological and molecular functions with significant group wide changes (p< or =0.05). Some of the expressed genes were further confirmed by quantitative RT-PCR (reverse transcription-polymerase chain reaction). RESULTS: Differences in gene expression were observed by identifying transcripts selected by t-test that were consistently changed by a minimum of two-fold. There were 195 transcripts that showed an increased expression and 109 transcripts that showed decreased expression relative to the osteoporotic condition. Of these, 75% transcripts were unknown gene products or ESTs (expressed sequence tag). A number of genes found in the aged and juvenile groups were not present in the osteoporotic rats. Functional clustering of the genes using the EASE bioinformatics program revealed that transcripts in osteoporosis were associated with signal transduction, lipid metabolism, protein metabolism, ionic and protein transport, neuropeptide and G protein signaling pathways. Although some of the genes have previously been shown to play a key role in osteoporosis, several genes were uniquely identified in this study and likely play a role in developing aged related osteoporosis that could have compelling implications in the development of new diagnostic strategies and therapeutics for osteoporosis. CONCLUSIONS: These data suggest that osteoporosis is associated with changes of multiple novel gene expression and that numerous pathways could play important roles in osteoporosis pathogenesis.

Age Factors↗

A relevant in vitro eukaryotic live-cell system for the evaluation of plasmodial protein localization.

Understanding the functional genomics and proteomics of plasmodia underpins the development of new approaches to antimalarial chemotherapy. Although genome databanks (e.g. PlasmoDB) and biocomputing tools (e.g. PlasMit, PlasmoAP, PATS) are useful in providing a global albeit predictive view of the myriad of about 5000 genes, only 40% are annotated, with few cases of endorsed subcellular localizations of the corresponding proteins in animal models. Progress in plasmodial protein trafficking has been hampered by the lack of a simple yet reliable method for studying subcellular localization of plasmodial proteins. In this study, we have used a combination of fluorescent markers, organelle-specific probes, phase contrast microscopy, and confocal microscopy to locate a selection of signal peptides from 10 plasmodial proteins in CHO-K1 cells. These eukaryotic cells serve as an in vitro living system for studying the cellular destinations of four mitochondrial-targeted TCA cycle proteins (citrate synthase, CS; isocitrate dehydrogenase, ICDH; branched chain alpha-keto-acid dehydrogenase E1alpha subunit, BCKDH; succinate dehydrogenase flavoprotein-subunit, SDH), two nuclear-targeted proteins (histone deacetylase, HDAC; RNA polymerase, RPOL), two apicoplast-targeted proteins (pyruvate kinase 2, PK2; glutamate dehydrogenase, GDH), and two cytoplasmic resident proteins (malate dehydrogenase, MDH; glycerol kinase, GK). The respective localizations of these malarial proteins have complied with the selected molecular targets, viz. mitochondrial, nuclear and cytoplasmic. Interestingly, MDH that is widely known to be resident in eukaryotic mitochondria was found to be cytoplasmic, probably due to the absence of molecular target sequences. Since the localization of plasmodial proteins is central to the authentication of their pathophysiological roles, this experimental system will serve as a useful a priori approach.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗

Normalized cDNA libraries from a porcine model of orthopedic implant-associated infection.

Staphylococcal infections that result from an alteration in a patient's immune response at the surgical site are a major problem in procedures that incorporate biomaterials in trauma surgery and joint replacement. Diagnosis of infection based on pathogen detection is difficult and exacerbated by increasing numbers of partially or totally resistant strains of nosocomial pathogens, particularly Staphylococcus aureus. Expression profiling of a host's cellular immune response could facilitate the identification of the pathways involved in pathogen recognition and eradication and could lead to more rational design of drugs and therapies. To this end, we constructed and characterized ten individually tagged and directionally cloned cDNA libraries from peripheral blood cells (PBC), spleen (Sp), thymus (Th), lymph node (LN), and bone marrow (BM) from immunologically naive and challenged pigs as part of an implant-associated orthopedic model of deep infection. Three of these libraries were normalized at C(0)(t) values 5, 10, 20, and 30. The libraries comprise more than 20 million primary transformants with an average insert length >1.4 kb. Cluster analysis of 7620 ESTs revealed 1029 clusters containing an average of 3.6 sequences and 3846 singletons. Gene discovery is estimated to be approximately 64%. Searches of public databases resulted in 49.3% annotated porcine sequences, of which 22.2% had significant homologies to ESTs from a variety of species, and 28.5% were without a significant match in any public database. We also identified 9.1% ESTs as involved in host cell and organism defense and 11.5% related to cell signaling and communication. These sequences, together with the 28.5% appearing as novel, are of specific interest to the infectious disease process.

Amino Acid Sequence↗

Confirmation of the expression of a large set of conserved hypothetical proteins in Shewanella oneidensis MR-1.

High-throughput "omic" technologies have allowed for a relatively rapid, yet comprehensive analysis of the global expression patterns within an organism in response to perturbations. In the current study, 9503 different tryptic peptides were identified with high confidence from capillary liquid chromatography-mass spectrometry analysis of 26 chemostat cultures of Shewanella oneidensis MR-1 under various conditions. Using at least one distinctive and a total of two total peptide identifications per protein, we detected the expression of 758 conserved hypothetical proteins. This included 359 such proteins previously described [Kolker, E., Picone, A.F., Galperin, M.Y., Romine, M.F., Higdon, R., Makarova, K.S., Kolker, N., Anderson, G.A., Qiu, X., Auberry, K.J., Babnigg, G., Beliaev, A.S., Edlefsen, P., Elias, D.A., Gorby, Y.A., Holzman, T., Klappenbach, J.A., Konstantinidis, K.T., Land, M.L., Lipton, M.S., McCue, L.A., Monroe, M., Pasa-Tolic, L., Pinchuk, G., Purvine, S., Serres, M.H., Tsapin, S., Zakrajsek, B.A., Zhu, W., Zhou, J., Larimer, F.W., Lawrence, C.E., Riley, M., Collart, F.R., Yates, J.R., III, Smith, R.D., Giometti, C.S., Nealson, K.H., Fredrickson, J.K., Tiedje, J.M., 2005. Global profiling of Shewanella oneidensis MR-1: expression of hypothetical genes and improved functional annotations. Proc Natl Acad Sci U S A 102, 2099-2104] with an additional 399 reported herein for the first time. The latter 399 proteins ranged from 5.3 to 208.3 kDa, with 44 being of 100 amino acid residues or less. Using a combination of information including peptide detection in cells grown under specific culture conditions and predictive algorithms such as PSORT and PSORT-B, possible/plausible functions are proposed for some conserved hypothetical proteins. Such proteins were found not only to be expressed, but 19 were only expressed under certain culturing conditions, thereby providing insight into potential functions. These findings also impact the genomic annotation for S. oneidensis MR-1 by confirming that these genes code for expressed proteins. Our results indicate that 399 proteins can now be upgraded from "conserved hypothetical protein" to "expressed protein in Shewanella," 19 of which appeared to be expressed under specific culture conditions.

Bacterial Proteins↗

The 630-kb lung cancer homozygous deletion region on human chromosome 3p21.3: identification and evaluation of the resident candidate tumor suppressor genes. The International Lung Cancer Chromosome 3p21.3 Tumor Suppressor Gene Consortium.

We used overlapping and nested homozygous deletions, contig building, genomic sequencing, and physical and transcript mapping to further define a approximately 630-kb lung cancer homozygous deletion region harboring one or more tumor suppressor genes (TSGs) on chromosome 3p21.3. This location was identified through somatic genetic mapping in tumors, cancer cell lines, and premalignant lesions of the lung and breast, including the discovery of several homozygous deletions. The combination of molecular manual methods and computational predictions permitted us to detect, isolate, characterize, and annotate a set of 25 genes that likely constitute the complete set of protein-coding genes residing in this approximately 630-kb sequence. A subset of 19 of these genes was found within the deleted overlap region of approximately 370-kb. This region was further subdivided by a nesting 200-kb breast cancer homozygous deletion into two gene sets: 8 genes lying in the proximal approximately 120-kb segment and 11 genes lying in the distal approximately 250-kb segment. These 19 genes were analyzed extensively by computational methods and were tested by manual methods for loss of expression and mutations in lung cancers to identify candidate TSGs from within this group. Four genes showed loss-of-expression or reduced mRNA levels in non-small cell lung cancer (CACNA2D2/alpha2delta-2, SEMA3B [formerly SEMA(V), BLU, and HYAL1] or small cell lung cancer (SEMA3B, BLU, and HYAL1) cell lines. We found six of the genes to have two or more amino acid sequence-altering mutations including BLU, NPRL2/Gene21, FUS1, HYAL1, FUS2, and SEMA3B. However, none of the 19 genes tested for mutation showed a frequent (>10%) mutation rate in lung cancer samples. This led us to exclude several of the genes in the region as classical tumor suppressors for sporadic lung cancer. On the other hand, the putative lung cancer TSG in this location may either be inactivated by tumor-acquired promoter hypermethylation or belong to the novel class of haploinsufficient genes that predispose to cancer in a hemizygous (+/-) state but do not show a second mutation in the remaining wild-type allele in the tumor. We discuss the data in the context of novel and classic cancer gene models as applied to lung carcinogenesis. Further functional testing of the critical genes by gene transfer and gene disruption strategies should permit the identification of the putative lung cancer TSG(s), LUCA, Analysis of the approximately 630-kb sequence also provides an opportunity to probe and understand the genomic structure, evolution, and functional organization of this relatively gene-rich region.

Carcinoma, Non-Small-Cell Lung↗

Structure of a helically extended SH3 domain of the T cell adapter protein ADAP.

The adapter protein ADAP (FYB/SLAP-130) provides a critical link between T cell receptor (TCR) signaling and cell adhesion via the activation of integrins. The C-terminal 70 residues of ADAP show homology to SH3 domains; however, conserved residues of the fold are absent. An alignment and annotation of this domain has therefore been elusive. We have solved the three-dimensional structure of the ADAP C-terminal domain by NMR spectroscopy and show that it represents an altered SH3 domain fold. An N-terminal, amphipathic helix makes extensive contacts to residues of the regular SH3 domain fold, and thereby a composite surface with unusual surface properties is created. We propose this SH3 domain variant to be classified as a helically extended SH3 domain (hSH3 domain) and show that the ADAP-hSH3 domain can no longer bind conventional proline-rich peptides.

Adaptor Proteins, Signal Transducing↗

Actin binding LIM protein 3 (abLIM3).

LIM domain proteins were demonstrated to play key roles in various biological processes such as embryonic development, cell lineage determination, and cancer differentiation. Actin binding LIM protein 1 (abLIM1) was reported to be localized in a genomic region often deleted in human cancers and suggested to be involved in axon guidance. Recently, existence of a second family member was reported, actin binding LIM protein 2. By means of computational biology and comparative genomics, we now characterized an additional, third member of the actin binding LIM protein subgroup, actin binding LIM protein 3 (abLIM3). The human mRNA sequence was previously annotated as differentially regulated in hepatoblastoma compared to normal livers. Conservation of key structural features of abLIM1 and abLIM2, four LIM domains and a VHD domain, suggested comparable biological function of abLIM3 as a linker between actin cytoskeleton and cell signaling pathways. AbLIM3 was found to be conserved in vertebrates, as orthologous sequences were characterized for mouse, fish, and frog. In addition, we report the existence of abLIM2 orthologs in fish and frog, suggesting a similar degree of evolutionary conservation. The intracellular localization of the abLIM3 protein was predicted to be nuclear by means of Reinhardt's neural network and the k-nearest neighbor algorithm. The corresponding abLIM3 gene was localized to chromosome 5q32 and spanned 119 kb, organized in 24 exons. An RT-PCR based expression profile available from the human unidentified gene-encoded (HUGE) database demonstrated highest expression for abLIM3 in heart, lung, liver, and brain/cerebellum accompanied by lower expression in multiple other tissues. Furthermore, abLIM3 was expressed in fetal liver, CNS, and spinal cord.

Amino Acid Sequence↗

An atlas of differential gene expression during early Xenopus embryogenesis.

We have carried out a large-scale, semi-automated whole-mount in situ hybridization screen of 8369 cDNA clones in Xenopus laevis embryos. We confirm that differential gene expression is prevalent during embryogenesis since 24% of the clones are expressed non-ubiquitously and 8% are organ or cell type specific marker genes. Sequence analysis and clustering yielded 723 unique genes displaying a differential expression pattern. Of these, 18% were already described in Xenopus, 47% have homologs and 35% are lacking significant sequence similarity in databases. Many of them encode known developmental regulators. We classified 363 of the 723 genes for which a Gene Ontology annotation for molecular function could be attributed and found 'DNA binding' and 'enzyme' the most represented terms. The most common protein domains encoded in these embryonic, differentially expressed genes are the homeobox and RNA Recognition Motif (RRM). Fifty-nine putative orthologs of human disease genes, and 254 organ or cell specific marker genes were identified. Markers were found for nasal placode and archenteron roof, organs for which a specific marker was previously unavailable. Markers were also found for novel subdomains of various other organs. The tissues for which most markers were found are muscle and epidermis. Expression of cell cycle regulators fell in two classes, containing proliferation-promoting and anti-proliferative genes, respectively. We identified 66 new members of the BMP4, chromatin, endoplasmic reticulum, and karyopherin synexpression groups, thus providing a first glimpse of their probable cellular roles. Cluster analysis of tissues to measure tissue relatedness yielded some unorthodox affinities besides expectable lineage relationships. In conclusion, this study represents an atlas of gene expression patterns, which reveals embryonic regionalization, provides novel marker genes, and makes predictions about the functional role of unknown genes.

Animals↗

Differential responses of stress genes to low dose-rate gamma irradiation.

In the past, most mechanistic studies of ionizing radiation response have employed very large doses, then extrapolated the results down to doses relevant to human exposure. It is becoming increasingly apparent, however, that this does not give an accurate or complete picture of the effects of most environmental exposures, which tend to be of low dose and protracted over time. We have initiated direct studies of low dose exposures, and using the relatively responsive ML-1 cell line, have shown that changes in gene expression can be triggered by doses of gamma-rays of 10 cGy and less in human cells. We have now extended these studies to investigate the effects on gene induction of reducing the rate of irradiation. In the ML-1 human myeloid leukemia cell line, we have found that reducing the dose rate over three orders of magnitude results in some protection against the induction of apoptosis, but still causes linear induction of the p53-regulated genes CDKN1A, GADD45A, and MDM2 between 2 and 50 cGy. Reducing the rate of exposure reduces the magnitude of induction of CDKN1A and GADD45A, but not the magnitude or duration of cell cycle delay. In contrast, MDM2 is induced to the same extent regardless of the rate of dose delivery. Microarray analysis has identified additional low dose-rate-inducible genes, and indicates the existence of two general classes of low dose-rate responders in ML-1. One group of genes is induced in a dose rate-dependent fashion, similar to GADD45A and CDKN1A. Functional annotation of this gene cluster indicates a preponderance of genes with known roles in apoptosis regulation. Similarly, a group of genes with dose rate-independent induction, such as seen for MDM2, was also identified. The majority of genes in this group are involved in cell cycle regulation. This apparent differential regulation of stress signaling pathways and outcomes in response to protracted radiation exposure has implications for carcinogenesis and risk assessment, and could not have been predicted from classical high dose studies.

Apoptosis↗

The contribution of farm animals to human health.

Farm animals and their products have a longstanding and successful history of providing significant contributions to human nutrition, clothing, facilitation of labour, research, development and medicine and have thus been essential in improving life expectancy and human health. With the advent of transgenic technologies the potential of farm animals for improving human health is growing and many areas remain to be explored. Recent breakthroughs in reproductive technologies, such as somatic cloning and in vitro embryo production, and their merger with molecular genetic tools, will further advance progress in this field. Here, we have summarized the contribution of farm animals to human health, covering the production of antimicrobial peptides, dietary supplements or functional foods, animals used as disease models and the contribution of animals to solving urgent environmental problems and challenges in medicine such as the shortage of human cells, tissues and organs and therapeutic proteins. Some of these areas have already reached the level of preclinical testing or commercial application, others will be further advanced only when the genomes of the animals concerned have been sequenced and annotated. Provided the necessary precautions are being taken, the transmission of pathogens from animals to humans can be avoided to provide adequate security. Overall, the promising perspectives of farm animals and their products warrant further research and development in this field.

Animal Structures↗

Cloning and functional analysis of cDNAs with open reading frames for 300 previously undefined genes expressed in CD34+ hematopoietic stem/progenitor cells.

Three hundred cDNAs containing putatively entire open reading frames (ORFs) for previously undefined genes were obtained from CD34+ hematopoietic stem/progenitor cells (HSPCs), based on EST cataloging, clone sequencing, in silico cloning, and rapid amplification of cDNA ends (RACE). The cDNA sizes ranged from 360 to 3496 bp and their ORFs coded for peptides of 58-752 amino acids. Public database search indicated that 225 cDNAs exhibited sequence similarities to genes identified across a variety of species. Homology analysis led to the recognition of 50 basic structural motifs/domains among these cDNAs. Genomic exon-intron organization could be established in 243 genes by integration of cDNA data with genome sequence information. Interestingly, a new gene named as HSPC070 on 3p was found to share a sequence of 105bp in 3' UTR with RAF gene in reversed transcription orientation. Chromosomal localizations were obtained using electronic mapping for 192 genes and with radiation hybrid (RH) for 38 genes. Macroarray technique was applied to screen the gene expression patterns in five hematopoietic cell lines (NB4, HL60, U937, K562, and Jurkat) and a number of genes with differential expression were found. The resource work has provided a wide range of information useful not only for expression genomics and annotation of genomic DNA sequence, but also for further research on the function of genes involved in hematopoietic development and differentiation.

Alternative Splicing↗

Developmental expression of 2489 gene clusters during pig embryogenesis: an expressed sequence tag project.

Identification of mRNAs that are present at early stages of embryogenesis is critical for a better understanding of development. To this end, cDNA libraries were constructed from germinal vesicle-stage oocytes, in vivo-produced four-cell- and blastocyst-stage embryos, and from in vitro-produced four-cell- and blastocyst-stage embryos. Randomly picked clones (10 848) were sequenced from the 3' end and those of sufficient quality (8066, 74%) were clustered into groups of sequence similarity (>95% identity), resulting in 2489 clusters. The sequence of the longest representative expressed sequence tag (EST) of each cluster was compared with GenBank and TIGR. Scores below 200 were considered unique, and 1114 (44.8%) did not have a match in either database. Sequencing from the 5' end yielded 12 of 37 useful annotations, suggesting that one third of the 1114 might be identifiable, still leaving over 700 unique ESTs. Virtual Northerns compared between the stages identified numerous genes where expression appears to change from the germinal vesicle oocyte to the four-cell stage, from the four-cell to blastocyst stage, and between in vitro- and in vivo-derived four-cell- and blastocyst-stage embryos. This is the first large-scale sequencing project on early pig embryogenesis and has resulted in the discovery of a large number of genes as well as possible stage-specific expression. Because many of these ESTs appear to not be in the public databases, their addition will be useful for transcriptional profiling experiments conducted on early pig embryos.

Animals↗