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Biomedical subjects

Kunio Inoue

Publications and source records attributed to Kunio Inoue.

5 recordsLinked to original sources
PubMed2003

A vertebrate RNA-binding protein Fox-1 regulates tissue-specific splicing via the pentanucleotide GCAUG.

Alternative splicing is one of the central mechanisms that regulate eukaryotic gene expression. Here we report a tissue-specific RNA-binding protein, Fox-1, which regulates alternative splicing in vertebrates. Fox-1 bound specifically to a pentanucleotide GCAUG in vitro. In zebrafish and mouse, fox-1 is expressed in heart and skeletal muscles. As candidates for muscle-specific targets of Fox-1, we considered two genes, the human mitochondrial ATP synthase gamma-subunit gene (F1gamma) and the rat alpha-actinin gene, because their primary transcripts contain several copies of GCAUG. In transfection experiments, Fox-1 induced muscle-specific exon skipping of the F1gamma gene via binding to GCAUG sequences upstream of the regulated exon. Fox-1 also regulated mutually exclusive splicing of the alpha-actinin gene, antagonizing the repressive effect of polypyrimidine tract-binding protein (PTB). It has been reported that GCAUG is essential for the alternative splicing regulation of several genes including fibronectin. We found that Fox-1 promoted inclusion of the fibronectin EIIIB exon. Thus, we conclude that Fox-1 plays key roles in both positive and negative regulation of tissue-specific splicing via GCAUG.

Actinin↗
PubMed2002

Regulation of alternative splicing of alpha-actinin transcript by Bruno-like proteins.

BACKGROUND: The Bruno-like or CELF proteins, such as mammalian CUGBP1 and Etr-3, Xenopus EDEN-BP, and Drosophila Bruno (Bru), are regulators of gene expression at the post-transcriptional level, and contain three RNA-recognition motifs (RRMs). It has been shown that mammalian CUGBP1 and Etr-3 regulate alternative splicing of cardiac troponin T pre-mRNA via binding to CUG-triplet repeats. RESULTS: Using in vitro selection and UV-crosslinking experiments, we found that zebrafish Bruno-like proteins bound to repeat elements of uridine and purine (termed UREs). It is known that non-muscle (NM) and smooth muscle (SM) exons of the rat alpha-actinin gene are used in a mutually exclusive manner. Transfection experiments in mammalian cells showed that zebrafish Brul and Etr-3 induced the muscle-specific splicing of rat alpha-actinin pre-mRNA via binding to the URE at the branch point upstream of the NM exon. In contrast, zebrafish Etr-1 promoted skipping of both the NM and SM exons in a manner which was not dependent on URE-binding. CONCLUSIONS: Our results showed that Bruno-like proteins bind to UREs and regulate the alternative splicing of alpha-actinin pre-mRNA. Members of the Bruno family play multiple roles in splicing regulation.

Actinin↗
PubMed2002

Zebrafish DAZ-like protein controls translation via the sequence 'GUUC'.

BACKGROUND: In many species, DAZ homologous genes encode RNA-binding proteins containing two conserved motifs, namely the RNA-recognition motif (RRM) and the DAZ motif. Genetic analysis and gene disruption studies have demonstrated that DAZ family proteins play important roles in gametogenesis. However, little is known about the biochemical functions of DAZ family proteins. RESULTS: Using in vitro selection and UV-crosslinking experiments, we identified the sequence 'GUUC' as the target RNA sequence of zebrafish DAZ-like protein (zDAZL). In transfection experiments, zDAZL protein activated translation in a manner dependent on the binding sequence in the 3'UTR of the Drosophila twine gene or zDazl gene. Moreover, it is highly likely that the zDAZL protein associates with polysomes through the DAZ motif in vivo, and that the association with polysomes is indispensable for translational activation. CONCLUSIONS: This is the first report that the DAZ family protein directly promotes the translation of the target mRNAs in vertebrates. This study provides important insights into the molecular mechanisms underlying the post-transcriptional regulation of DAZ family proteins in gametogenesis.

3' Untranslated Regions↗
PubMed2002

The germ cell lineage identified by vas-mRNA during the embryogenesis in goldfish.

vas RNA has been identified in germ-line cells and its precursors in zebrafish, with the result that the germ-line lineage can be traced throughout embryogenesis. In the present study, we described vas localization and the migration of vas-positive cells in goldfish, using whole mount in situ hybridization. The signals of vas mRNA localization appeared at the marginal part of the first to third cleavage planes. The eight signals were detected during the period from the 8- cells to the 512-cell stage. At the late-blastula stage, additional numbers of vas-positive cells were observed, suggesting the proliferation of these cells. At the segmentation period, vas-positive cells showed a long extended distribution along the embryonic axis, but did not form any clusters. vas-positive cells were occasionally distributed at the head region, especially around the future otic vesicle. These signals were inherited to the primordial germ cells, suggesting that vas-positive cells were primordial germ cells (PGCs) in goldfish.

Animals↗