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At least 415 records · Page 23Linked to original sources
PubMed2001

Transposon tagging in maize.

Through recent government- and industry-sponsored efforts, several forward and reverse genetic screening programs have emerged over the past few years to aid in the genetic dissection of gene function in maize. Despite a US maize crop valued at $18.4 billion last year (http://www.ncga.com/03world/main/US_crop_value_2000.html) and rich genetic history, maize has taken a back seat to Arabidopsis thaliana as the model genetic system for plants over the past decade. With a fully sequenced genome, short generation time and small size, studies of Arabidopsis have provided plant scientists with a molecular framework for hormonal, developmental and environmental signaling pathways in plants. As investigations into Arabidopsis continue, our capacity to engineer biochemical pathways and alter plant physiological responses will become increasingly sophisticated. Nevertheless, approximately 130 million years have passed since monocot and higher eudicot lineages diverged. Thus, our ability to engineer agronomically important monocot grasses such as maize, rice and wheat will become increasingly limited by our lack of understanding of the physiological and morphological differences that have evolved in the monocots and higher eudicots. The sophisticated transposon collections now being generated for maize are but one of several recent projects (http://www.nsf.gov/bio/pubs/awards/genome01.htm) to provide grass researchers with essential tools for genome analysis. Because grain crops are such a closely related group, it is hoped that many of the findings made in one grass will be directly applicable to understanding the biology of another. The goal of this review is to highlight the recent developments in maize transposon-based gene characterization programs and provide a critical examination of the advantages and disadvantages each system offers.

DNA Transposable Elements↗
PubMed2004

Transformation of Fusarium oxysporum by particle bombardment and characterisation of the resulting transformants expressing a GFP transgene.

Fusarium is the causative agent of a variety of economically significant vascular wilt diseases of vegetables, flowers and field crops. The completion of the first Fusarium genome and the availability of an EST database now provides a platform for both forward and reverse genetic approaches to ascribe gene function in this phytopathogen. To underpin these strategies effective gene transfer procedures will be required. Here we describe an efficient and robust procedure for Fusarium oxysporum transformation based on particle bombardment. We utilised this procedure to introduce a chimeric gene comprised of the Aspergillus nidulans Pgdp promoter fused to a GFP reporter gene. A transformation efficiency of 45 transformants per mug of plasmid DNA was routinely achieved. The Pgdp promoter directed strong cytoplasmic expression of the GFP marker in transformed F. oxysporum monitored via fluorescence and confocal microscopy. A pathogenicity assay undertaken on Arabidopsis seedlings with selected transformants revealed that virulence was retained following transformation. Moreover, in a similar fashion to wild-type F. oxysporum, these transformants activated three distinct Arabidopsis defence gene promoter::luciferase fusions, which defined specific defence gene subsets.

Arabidopsis↗
PubMed2005

[Dercum's disease: a severe complication in a rare disease. A case report].

Dercum's disease or adiposis dolorasa is unusual and unknown. Four symptoms are typical. It is characterized by painful subcutaneous fatty tumors in postmenopausal woman. We present this disease through the study of an uncommon clinical case: a sceptic choc following the "steato-cutaneous-necrosis" of a fatty tumor. The disease remains rare. The etiology is to this day unknown and different hypothesis (endocrinous, metabolic, genetics) are put forward. Multiple complications can occur but severe septicemia is rare. The treatment can be medical (loss of weight, corticoids, intravenous lidocaine) or surgical (surgical excision or liposuction).

Adiposis Dolorosa↗
PubMed2006

Peroxisomal beta-oxidation--a metabolic pathway with multiple functions.

Fatty acid degradation in most organisms occurs primarily via the beta-oxidation cycle. In mammals, beta-oxidation occurs in both mitochondria and peroxisomes, whereas plants and most fungi harbor the beta-oxidation cycle only in the peroxisomes. Although several of the enzymes participating in this pathway in both organelles are similar, some distinct physiological roles have been uncovered. Recent advances in the structural elucidation of numerous mammalian and yeast enzymes involved in beta-oxidation have shed light on the basis of the substrate specificity for several of them. Of particular interest is the structural organization and function of the type 1 and 2 multifunctional enzyme (MFE-1 and MFE-2), two enzymes evolutionarily distant yet catalyzing the same overall enzymatic reactions but via opposite stereochemistry. New data on the physiological roles of the various enzymes participating in beta-oxidation have been gathered through the analysis of knockout mutants in plants, yeast and animals, as well as by the use of polyhydroxyalkanoate synthesis from beta-oxidation intermediates as a tool to study carbon flux through the pathway. In plants, both forward and reverse genetics performed on the model plant Arabidopsis thaliana have revealed novel roles for beta-oxidation in the germination process that is independent of the generation of carbohydrates for growth, as well as in embryo and flower development, and the generation of the phytohormone indole-3-acetic acid and the signal molecule jasmonic acid.

Acetyl-CoA C-Acyltransferase↗
PubMed2006

RNA interference in cancer.

In the recent years, RNA interference (RNAi) has emerged as a major regulatory mechanism in eukaryotic gene expression. The realization that changes in the levels of microRNAs are directly associated with cancer led to the recognition of a new class of tumor suppressors and oncogenes. Moreover, RNAi has been turned into a potent tool for artificially modulating gene expression through the introduction of short interfering RNAs. A plethora of individual inhibitory RNAs as well as several large collections of these reagents have been generated. The systems for stable and regulated expression of these molecules emerged as well. These tools have helped to delineate the roles of various cellular factors in oncogenesis and tumor suppression and laid the foundation for new approaches in gene discovery. Furthermore, successful inhibition of tumor cell growth by RNAi aimed at oncogenes in vitro and in vivo supports the enthusiasm for potential therapeutic applications of this technique. In this article we review the evidence of microRNA involvement in cancer, the use of short interfering RNAs in forward and reverse genetics of this disease, and as well as both the benefits and limitations of experimental RNAi.

Animals↗
PubMed2006

CEACAMs: their role in physiology and pathophysiology.

Carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) belong to a group of mammalian immunoglobulin-related glycoproteins. They are involved in cell-cell recognition and modulate cellular processes that range from the shaping of tissue architecture and neovascularization to the regulation of insulin homeostasis and T-cell proliferation. CEACAMs have also been identified as receptors for host-specific viruses and bacteria in mice and humans, respectively, making these proteins an interesting example of pathogen-host co-evolution. Forward and reverse genetics in the mouse now provide powerful novel models to elucidate the action of CEACAM family members in vivo.

Animals↗
PubMed2004

Bioinformatics: harvesting information for plant and crop science.

Bioinformatics is an integral aspect of plant and crop science research. Developments in data management and analytical software are reviewed with an emphasis on applications in functional genomics. This includes information resources for Arabidopsis and crop species, and tools available for analysis and visualisation of comparative genomic data. Approaches used to explore relationships between plant genes and expressed sequences are compared, including use of ontologies. The impact of bioinformatics in forward and reverse genetics is described, together with the potential from data mining. The role of bioinformatics is explored in the wider context of plant and crop science.

Algorithms↗
PubMed2006

Xenopus as a model system for vertebrate heart development.

The African clawed frog, Xenopus laevis, is a valuable model system for studies of vertebrate heart development. In the following review, we describe a range of embryological and molecular methodologies that are used in Xenopus research and discuss key discoveries relating to heart development that have been made using this model system. We also discuss how the sequence of the Xenopus tropicalis genome provides a valuable tool for identification of orthologous genes and for identification of evolutionarily conserved promoter elements. Finally, both forward and reverse genetic approaches are currently being applied to Xenopus for the study of vertebrate heart development.

Animals↗
PubMed2005

A whole lotta jumpin' goin' on: new transposon tools for vertebrate functional genomics.

Genome sequences of vertebrate model organisms are becoming available, fuelling the next challenging phase of research: annotating all of the genes with functional information. The functional annotation of all of the approximately 35 000 genes in mammals will undoubtedly require complementing the technologies of forward and reverse genetics in mutagenesis screens. Two recent articles report on the construction of retrotransposable elements that efficiently 'jump' in mammalian cells. These new elements hold great promise as useful vectors for insertional mutagenesis screens in the mouse.

Animals↗
PubMed2005

The dual nature of homologous recombination in plants.

Homologous recombination creates covalent linkages between DNA in regions of highly similar or identical sequence. Recent results from several laboratories, many of them based on forward and reverse genetics in Arabidopsis, give insights into the mechanisms of the enzymatic machinery and the involvement of chromatin in somatic and meiotic DNA recombination. Also, signaling pathways and interconnections between repair pathways are being discovered. In addition, recent work shows that biotic and abiotic influences from the environment can dramatically affect plant genomes. The resulting changes in the DNA sequence, exerted at the level of somatic or meiotic tissue, might contribute to evolution.

Arabidopsis↗
PubMed2006

High-throughput zebrafish histology.

The morphological effects of mutation and disease are often critical to our understanding of normal and abnormal function. The power and popularity of zebrafish as a forward and reverse genetic vertebrate model system, combined with its small size, have made it an ideal model in which to study the genetics of histologically scorable phenotypes. The presence of multiple tissue types in this organism's small larvae also makes it a potentially important model for toxicological analysis. Studying histological phenotypes is greatly enhanced by high-throughput methods of histology. Here, we describe details of high-throughput histology of the zebrafish using larval arrays, along with recent advances in mold design and discussion of work in progress that will lead to easier ways for people in the field to more rapidly score phenotypes in arrays. These detailed descriptions, together with the troubleshooting guide, should enable any laboratory with ties to a histology facility to perform high-throughput histology of zebrafish.

Animals↗
PubMed2002

Functional genomics: the coming of age for Tetrahymena thermophila.

Over the past decade, researchers have manipulated the unique biology of Tetrahymena thermophila to generate a premier experimental organism for functional genomic analysis. A diverse array of DNA transformation methods have spearheaded in vivo strategies for discovering and dissecting universal eukaryotic processes, such as telomere addition and chromatin remodeling. Compartmentalization of this protist's genome into two functionally distinct nuclei - the silent 'germline' micronucleus and the transcriptionally active macronucleus - provides a powerful means for controlling the expression of transgenes. Heterokaryons that silently harbor homozygous recessive mutations (including lethal ones) in the germline have been exploited. The coupling of forward and reverse genetic approaches with genomics-based methods for gene discovery presents a bright future for research in this rising model eukaryote.

Animals↗
PubMedDate not supplied

How to characterize meiotic functions in plants?

Our understanding of plant meiosis is rapidly increasing thanks to the model Arabidopsis thaliana. Here we present the results of a screening for meiotic mutants carried out with a library containing 30,719 T-DNA insertion lines. An average of one mutant per 1000 lines was recovered. Several phenotypic classes could be distinguished and are presented. In parallel, 39 proteins known to be involved in meiosis in non-plant organisms were chosen and a search was performed for homologue sequences in the completed Arabidopsis thaliana genome. Approximately 30% of the meiotic related sequences showed similarities with one or several Arabidopsis putative genes. The relevance of forward versus reverse genetics in order to characterize meiotic functions is discussed.

Arabidopsis↗
PubMed2001

Strategies to identify transport systems in plants.

Since the first molecular structures of plant transporters were discovered over a decade ago, considerable advances have been made in the study of plant membrane transport, but we still do not understand transport regulation. The genes encoding the transport systems in the various cell membranes are still to be identified, as are the physiological roles of most transport systems. A wide variety of complementary strategies are now available to study transport systems in plants, including forward and reverse genetics, proteomics, and in silico exploitation of the huge amount of information contained in the completely known genomic sequence of Arabidopsis.

Amino Acid Sequence↗
PubMed2004

A PCR-based assay to detect hAT-like transposon sequences in plants.

Despite their potential as endogenous tools for forward and reverse genetics, members of the hobo, Ac, Tam3 (or hAT) superfamily of transposable elements have been characterized in but a limited number of plant species. To expedite their isolation, we developed a PCR-based assay for the detection of hAT-like transposon sequences in plants which was applied to isolate and initially characterize such sequences from Petunia hybrida, Phaseolus vulgaris, Bambusa vulgaris, Brassica napus and Rhododendron simsii.

DNA Transposable Elements↗
PubMed2003

Technicolour transgenics: imaging tools for functional genomics in the mouse.

Over the past decade, a battery of powerful tools that encompass forward and reverse genetic approaches have been developed to dissect the molecular and cellular processes that regulate development and disease. The advent of genetically-encoded fluorescent proteins that are expressed in wild type and mutant mice, together with advances in imaging technology, make it possible to study these biological processes in many dimensions. Importantly, these technologies allow direct visual access to complex events as they happen in their native environment, which provides greater insights into mammalian biology than ever before.

Animals↗
PubMed2005

Storage reserve mobilization in germinating oilseeds: Arabidopsis as a model system.

Germinating oilseeds break down fatty acids through peroxisomal beta-oxidation and convert the carbon into soluble carbohydrates through the glyoxylate cycle and gluconeogenesis. This interconversion is unique among higher eukaryotes. Using a combination of forward and reverse genetic screens, we have isolated mutants that compromise fatty acid breakdown at each step. These mutants exhibit characteristic, yet nonidentical, seedling establishment phenotypes that can be rescued by the provision of an alternative carbon source. In addition, we have recently shown that Arabidopsis seed's lipid breakdown occurs in two distinct tissues, the embryo and endosperm. The utilization of endospermic lipid reserves requires gluconeogenesis and transport of the resulting sugars to the germinating embryo. We discuss the potential of the Arabidopsis endosperm tissue as a simplified model system for the study of germination and lipid breakdown in germinating oilseeds.

Arabidopsis↗
PubMed2005

A role of SAND-family proteins in endocytosis.

Caenorhabditis elegans has recently been used as an attractive model system to gain insight into mechanisms of endocytosis in multicellular organisms. A combination of forward and reverse genetics has identified a number of new membrane trafficking factors. Most of them have mammalian homologues which function in the same transport events. We describe a novel C. elegans gene sand-1, whose loss of function causes profound endocytic defects in many tissues. SAND-1 belongs to a conserved family of proteins present in all eukaryotic species, whose genome is sequenced. However, SAND family has not been previously characterized in metazoa. Our comparison of C. elegans SAND-1 and its yeast homologue, Mon1p, showed a conserved role of the SAND-family proteins in late steps of endocytic transport.

Animals↗