Takuya Umehara

Learn More
Persistent infection with hepatitis C virus (HCV) is a major cause of liver diseases such as chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. Here we report that inhibition of heat shock protein 90 (Hsp90) is highly effective in suppressing HCV genome replication. In HCV replicon cells, HCV replication was reduced by Hsp90 inhibitors and by(More)
The hepatitis C virus (HCV) non-structural protein 3 (NS3) is a multifunctional enzyme with protease and helicase activities. It is essential for HCV proliferation and is therefore a target for anti-HCV drugs. Previously, we obtained RNA aptamers that inhibit either the protease or helicase activity of NS3. During the present study, these aptamers were used(More)
The hepatitis C virus non-structural protein 3 (HCV NS3) possesses both protease and helicase activities that are essential for viral replication. In a previous study, we obtained RNA aptamers that specifically and efficiently inhibited NS3 protease activity (G9 aptamers). In order to add helicase-inhibition capability, we attached (U)14 to the 3'-terminal(More)
Lipids are key components in the viral life cycle that affect host-pathogen interactions. In this study, we investigated the effect of HCV infection on sphingolipid metabolism, especially on endogenous SM levels, and the relationship between HCV replication and endogenous SM molecular species. We demonstrated that HCV induces the expression of the genes(More)
The internal ribosome entry site (IRES) is important for translation of hepatitis C virus (HCV) mRNA and has a unique RNA structure containing conserved domains I to IV. To investigate the function of domain II, we selected RNA aptamers that bind to domain II of HCV IRES by applying a simple and convenient selection method using a hybridized tag for fixing(More)
BACKGROUND Although no potential homologues of multicellular apoptotic genes (e.g. Bax, Bak, Bcl-2, caspases and p53) have been identified in a unicellular eukaryote, previous reports contain several implications of the apoptotic behaviour of yeasts (i.e. Saccharomyces cerevisiae and Schizosaccharomyces pombe). Therefore, whether or not yeast undergoes(More)
O-Phosphoserine (Sep), the most abundant phosphoamino acid in the eukaryotic phosphoproteome, is not encoded in the genetic code, but synthesized posttranslationally. Here, we present an engineered system for specific cotranslational Sep incorporation (directed by UAG) into any desired position in a protein by an Escherichia coli strain that harbors a(More)
Nonstructural protein 3 (NS3) of hepatitis C virus (HCV) is a multi-functional enzyme having protease and helicase activities. NS3 is essential for HCV replication and proliferation. Previously, we obtained RNA aptamers against NS3 protease domain (Protease aptamer; deltaNEO-III and G9-II) and helicase domain (helicase aptamer; #5), and they inhibited the(More)
RNA interference (RNAi) is a sequence-specific post-transcriptional gene silencing by double-stranded RNA. Because the phenomenon is conserved and ubiquitous in mammalian cells, RNAi has considerable therapeutic potential for human pathogenic gene products. Recent studies have demonstrated the clinical potential of logically designed small interfering RNA(More)
We report the isolation of a cDNA encoding a new type of transcription factor S-II, termed h-SII-T1, from a human library. The mRNA corresponding to the clone is highly expressed in testis and ovary. Comparison of the deduced amino acid (aa) sequence with those of other S-II molecules shows that (i) the C-terminal zinc finger (Zf) domain is highly(More)