Chikara Masuta

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Viroids and most viral satellites have small, noncoding, and highly structured RNA genomes. How they cause disease symptoms without encoding proteins and why they have characteristic secondary structures are two longstanding questions. Recent studies have shown that both viroids and satellites are capable of inducing RNA silencing, suggesting a possible(More)
Double-stranded (ds) RNAs and imperfect hairpin RNAs of endogenous genes trigger post-transcriptional gene silencing (PTGS) and are cleaved by a Dicer-like nuclease into small interfering RNAs (siRNAs) and microRNs (miRNAs), respectively. Such small RNAs (siRNAs and miRNAs) then guide an RNA-induced silencing complex (RISC) for sequence-specific RNA(More)
Classical genetic analysis has revealed that the determinate habit of soybean (Glycine max) is controlled by a recessive allele at the determinate stem (Dt1) locus. To dissect the molecular basis of the determinate habit, we isolated two orthologs of pea (Pisum sativum) TERMINAL FLOWER1a, GmTFL1a and GmTFL1b, from the soybean genome. Mapping analysis(More)
Symptoms on virus-infected plants are often very specific to the given virus. The molecular mechanisms involved in viral symptom induction have been extensively studied, but are still poorly understood. Cucumber mosaic virus (CMV) Y satellite RNA (Y-sat) is a non-coding subviral RNA and modifies the typical symptom induced by CMV in specific hosts; Y-sat(More)
S-Adenosylhomocysteine hydrolase (SAHH) is a key enzyme in transmethylation reactions that use S-adenosylmethionine as the methyl donor. Because of the importance of SAHH in a number of S-adenosylmethionine-dependent transmethylation reactions, particularly the 5' capping of mRNA during viral replication, SAHH has been considered as a target of potential(More)
We examined the correlation of the amino acid at position 129 in the coat protein (CP) of cucumber mosaic virus (CMV) with the phenotype of the viral pathology in tobacco by using CP mutants in which several amino acid substitutions had been introduced. An exchange between Ser129 in CMV-Y, a chlorosis-inducing strain, and Pro129 of CMV-O, a(More)
We previously analyzed hybrids of Cucumber mosaic virus (CMV) and Tomato aspermy virus (TAV) that contained CMV RNA2 with the 3'-terminal sequence from TAV RNA2. In this article, we scrutinized the RNA3 molecules in these hybrid viruses by Northern hybridization and RT-PCR and found some recombinant CMV RNA3 molecules and various recombinant RNA4 molecules(More)
S-adenosyl-l-homocysteine hydrolase (SAHH) is a key enzyme in the regulation of intracellular methylation reactions. To investigate the role of SAHH in methylation reactions and morphogenesis in planta, we have made transgenic plants expressing antisense RNA of tobacco SAHH. The transgenic plants displayed distinct morphological changes including a floral(More)
Full-length DNA copies of RNAs 1, 2, and 3 of CMV Y strain (CMV-Y) were cloned downstream of modified phage T7 promoter sequences to obtain infectious RNA transcripts. The small number of extra nonviral nucleotides at the 5' ends considerably decreased the specific infectivity of the transcripts of RNAs 1 and 2 but did not affect that of the RNA3(More)
Small interfering RNAs (siRNAs) are key molecules in RNA silencing, which includes posttranscriptional gene silencing, cosuppression, quelling, and RNA interference. The presence of siRNAs indicates RNA silencing in cells. We present a method of detecting siRNAs using nonradioactive probes that involves isolating the small RNA fraction, separating siRNAs(More)