MediGene

About: MediGene is a company organization based out in Planegg, Germany. It is known for research contribution in the topics: Antigen & Epitope. The organization has 196 authors who have published 135 publications receiving 5314 citations.

Analysis of 1.9 Mb of contiguous sequence from chromosome 4 of Arabidopsis thaliana

Abstract: The plant Arabidopsis thaliana (Arabidopsis) has become an important model species for the study of many aspects of plant biology. The relatively small size of the nuclear genome and the availability of extensive physical maps of the five chromosomes provide a feasible basis for initiating sequencing of the five chromosomes. The YAC (yeast artificial chromosome)-based physical map of chromosome 4 was used to construct a sequence-ready map of cosmid and BAC (bacterial artificial chromosome) clones covering a 1.9-megabase (Mb) contiguous region, and the sequence of this region is reported here. Analysis of the sequence revealed an average gene density of one gene every 4.8 kilobases (kb), and 54% of the predicted genes had significant similarity to known genes. Other interesting features were found, such as the sequence of a disease-resistance gene locus, the distribution of retroelements, the frequent occurrence of clustered gene families, and the sequence of several classes of genes not previously encountered in plants.

Multiplex Human Papillomavirus Serology Based on In Situ-Purified Glutathione S-Transferase Fusion Proteins,

Abstract: Background: More than 100 different human papillomaviruses (HPVs) can cause proliferative diseases, many of which are malignant, such as cervical cancer. HPV serology is complex because infection and disease lead to distinct type-specific antibody responses. Using bead-based technology, we have developed an assay platform that allows the simultaneous detection of antibodies against up to 100 in situ affinity–purified recombinant HPV proteins. Methods: Twenty-seven HPV proteins were expressed as glutathione S -transferase fusion proteins and affinity-purified in one step by incubation of glutathione-displaying beads in bacterial lysate. Spectrally distinct bead sets, each carrying one particular antigen, were mixed, incubated with serum, and differentiated in a flow cytometer-like analyzer (xMAP; Luminex Corp). Antibodies bound to the antigens were detected via fluorescent secondary reagents. We studied 756 sera from 2 case-control studies of cervical cancer. Results: Glutathione S -transferase fusion proteins bound with high affinity to glutathione-displaying beads ( K d = 6.9 × 10−9 mol/L). The dynamic range of multiplex serology covered 1.5 orders of magnitude, and antibodies were detected at serum dilutions >1:1 000 000. Imprecision (median CV) was ≤5.4%, and assay reproducibility was high ( R 2 = 0.97). Results on clinical samples showed high concordance with ELISA (κ = 0.846), but multiplex serology exhibited increased detection of weak antibody responses. Antibodies to the E6 oncoproteins of the rare HPV types 52 and 58 were associated with cervical cancer ( P <0.001). Conclusion: Multiplex serology enables antibody analyses of large numbers of sera against up to 100 antigens in parallel and has the potential to replace ELISA technology.

The nucleotide sequence of Saccharomyces cerevisiae chromosome VII.

Abstract: Here we report the sequence of 569,202 base pairs of Saccharomyces cerevisiae chromosome V. Analysis of the sequence revealed a centromere, two telomeres and 271 open reading frames (ORFs) plus 13 tRNAs and four small nuclear RNAs. There are two Ty1 transposable elements, each of which contains an ORF (included in the count of 271). Of the ORFs, 78 (29%) are new, 81 (30%) have potential homologues in the public databases, and 112 (41%) are previously characterized yeast genes.

Mammosphere culture of metastatic breast cancer cells enriches for tumorigenic breast cancer cells

Abstract: The identification of potential breast cancer stem cells is of importance as the characteristics of stem cells suggest that they are resistant to conventional forms of therapy. Several techniques have been proposed to isolate or enrich for tumorigenic breast cancer stem cells, including (a) culture of cells in non-adherent non-differentiating conditions to form mammospheres and (b) sorting of the cells by their surface phenotype (expression of CD24 and CD44). We have cultured metastatic cells found in pleural effusions from breast cancer patients in non-adherent conditions without serum to form mammospheres. Dissociated cells from these mammospheres were used to determine the tumorigenicity of these cultures. Expression of CD24 and CD44 on uncultured cells and mammospheres derived from the pleural effusions was documented. We found that the majority (20/27) of the pleural effusions tested contained cells capable of forming mammospheres of varying sizes that could be passaged. After dissociation and plating with serum onto adherent dishes, the cells can differentiate, as determined by the increased expression of cytokeratins and MUC1. Analysis of surface expression of CD24 and CD44 on uncultured cells from 21 of the samples showed that the cells from some samples separated into two populations, but some did not. The proportion of cells that could be considered CD44+/CD24low/- was highly variable and did not appear to correlate with the ability to form the larger mammospheres. Of eight pleural effusion mammospheres tested in severe combined immunodeficiency disease (SCID) mice, four were found to induce tumours when only 5,000 or fewer cells were injected, whereas the same number of uncultured cells did not form tumours. The ability to induce tumours appeared to correlate with the ability to produce the larger mammospheres. Uncultured cells from a highly tumorigenic sample (PE14) were uniformly negative for surface expression of both CD24 and CD44. This paper shows, for the first time, that mammosphere culture of pleural effusions enriches for cells capable of inducing tumours in SCID mice. The data suggest that mammosphere culture of these metastatic cells could provide a highly appropriate model for studying the sensitivity of the tumorigenic 'stem' cells to therapeutic agents and for further characterisation of the tumour-inducing subpopulation of breast cancer cells.

DNA helicase‐mediated packaging of adeno‐associated virus type 2 genomes into preformed capsids

Abstract: Helicases not only catalyse the disruption of hydrogen bonding between complementary regions of nucleic acids, but also move along nucleic acid strands in a polar fashion. Here we show that the Rep52 and Rep40 proteins of adeno-associated virus type 2 (AAV-2) are required to translocate capsid-associated, single-stranded DNA genomes into preformed empty AAV-2 capsids, and that the DNA helicase function of Rep52/40 is essential for this process. Furthermore, DNase protection experiments suggest that insertion of AAV-2 genomes proceeds from the 3' end, which correlates with the 3'-->5' processivity demonstrated for the Rep52/40 helicase. A model is proposed in which capsid-immobilized helicase complexes act as molecular motors to 'pump' single-stranded DNA across the capsid boundary.