S. B. Hasegawa

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Exposure to asbestos is a known etiological factor in malignant mesothelioma (MM). However, in vitro cell culture studies have provided paradoxical evidence that asbestos exposure to mesothelial cells causes cytotoxicity or apoptosis rather than malignant transformation. Although it has been shown that the iron associated with asbestos participates in the(More)
Tetrahymena ribozymes hold promise for repairing genetic disorders but are largely limited by their modest splicing efficiency and low production of final therapeutic proteins. Ribozyme evolution in intact living mammalian cells would greatly facilitate the discovery of new ribozyme variants with high in vivo activity, but no such strategies have been(More)
The Tetrahymena trans-splicing ribozyme can edit RNA in a sequence-specific manner, but its efficiency needs to be improved for any functional rescues. This communication describes a simple method that uses a bacterial enzyme beta-lactamase to report trans-splicing activity of Tetrahymena ribozyme in single living mammalian cells by fluorescence microscopy(More)
Noninvasive imaging of specific mRNAs in living subjects promises numerous biological and medical applications. Common strategies use fluorescently or radioactively labelled antisense probes to detect target mRNAs through a hybridization mechanism, but have met with limited success in living animals. Here we present a novel molecular imaging approach based(More)
The internal guiding sequence (IGS) is normally located at the 5' end of trans-splicing ribozymes that are derived from the Tetrahymena group I intron, and is required for the recognition of substrate RNAs and for trans-splicing reactions. Here, we separated the Tetrahymena group I intron at the L2 loop to produce two fragments: the IGS-containing(More)
The detection of mRNA expression in vivo can reveal essential information about basic biology and disease processes. Current methods primarily involve the use of labeled (with fluoro-phores or radioactive isotopes) antisense oligomers, based on a one-to-one receptor–ligand type of interaction without robust signal amplification, such as molecular beacons.(More)
For tumor radiotherapy, the in vivo detection of early cellular responses is important for predicting therapeutic efficacy. Mn(2+) is used as a positive contrast agent in manganese-enhanced MRI (MEMRI) and is expected to behave as a mimic of Ca(2+) in many biologic systems. We conducted in vitro and in vivo MRI experiments with Mn(2+) to investigate whether(More)
H-ferritin (HF) is a core subunit of the iron storage protein ferritin, and plays a central role in the regulation of cellular iron homeostasis. Recent studies revealed that ferritin and HF are involved in a wide variety of iron-independent functions, including regulating biological processes during physiological and pathological conditions, and can be(More)
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