Small interfering RNAs (siRNAs) are a key component of RNA silencing, including cosuppression. Here, we show an example in which siRNA does not serve in the downregulation of target genes. A tobacco endoplasmic reticulum omega-3 fatty acid desaturase (NtFAD3) catalyzes the formation of alpha-linolenate (18:3). Introduction of the NtFAD3 gene into tobacco plants caused strong reduction of 18:3 content in leaf tissues, which is associated with the production of the NtFAD3 siRNAs. However, this silencing effect was lacking in the root tissues. Both the introduced NtFAD3 and endogenous NtFAD3 genes were expressed successfully, and the roots showed increased 18:3 phenotype. Surprisingly, the NtFAD3 siRNAs were produced even in the root tissues. Expression of a hairpin double-stranded RNA against the NtFAD3 gene caused efficient reduction of 18:3 content in root tissues. Therefore, cosuppression of the NtFAD3 gene in tobacco appears to include an as yet unidentified developmental stage and tissue-specific mechanism of regulation of siRNA function.
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http://dx.doi.org/10.1016/j.febslet.2004.07.063 | DOI Listing |
Int J Biol Macromol
June 2024
College of Agronomy/Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Shanxi Engineering Research Center for Genetics and Metabolism of Special Crops, Taigu, Shanxi, China. Electronic address:
The basic leucine zipper (bZIP) transcription factors (TFs) function importantly in numerous life processes in plants. However, bZIP members and their biological roles remain unknown in Camelina sativa, a worldwide promising oil crop. Here, 220 CsbZIP proteins were identified in camelina and classified into thirteen groups.
View Article and Find Full Text PDFPLoS One
January 2015
Graduate School of Advanced Integration Science, Chiba University, Inage-ku, Chiba, Japan.
Sense transgene-induced post-transcriptional gene silencing (S-PTGS) is thought to be a type of RNA silencing in which ARGONAUTE1 directs the small interfering RNA (siRNA)-mediated cleavage of a target mRNA in the cytoplasm. Here, we report that the altered splicing of endogenous counterpart genes is a main cause for the reduction of their mature mRNA levels. After the S-PTGS of a tobacco endoplasmic reticulum ω-3 fatty acid desaturase (NtFAD3) gene, 3'-truncated, polyadenylated endo-NtFAD3 transcripts and 5'-truncated, intron-containing endo-NtFAD3 transcripts were detected in the total RNA fraction.
View Article and Find Full Text PDFFEBS J
April 2010
Graduate School of Horticulture, Chiba University, Japan.
RNA silencing is an epigenetic inhibition of gene expression and is guided by small interfering RNAs. Sense transgene-induced post-transcriptional gene silencing (S-PTGS) occurs in a portion of a transgenic plant population. When a sense transgene encoding a tobacco endoplasmic reticulum omega-3 fatty acid desaturase (NtFAD3) was introduced into tobacco plants, an S-PTGS line, S44, was obtained.
View Article and Find Full Text PDFPlant Mol Biol
April 2007
Graduate School of Science and Technology, Chiba University, Chiba, Japan.
Small interfering RNA (siRNA) species with 21-25 nucleotides in length guide mRNA cleavage, translational arrest, and heterochromatin formation in RNA interference (RNAi). To delineate the target region of RNAi, a construct harboring a transcriptional fusion between parts of the target mRNA and the beta-glucuronidase gene was biolistically delivered into tobacco leaves showing an RNAi phenotype and the assay sequence was transiently expressed. The RNAi effect was monitored by amplification of this chimeric transcript.
View Article and Find Full Text PDFPlant Cell Rep
May 2007
Graduate School of Science and Technology, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522 Japan.
RNA interference (RNAi) has been used to suppress gene expression in various eukaryotic organisms. In plants, RNAi can be induced by introduction of an RNAi vector that transcribes a self-complementary hairpin RNA. Most basic RNAi constructs have an inverted repeat interrupted with a spacer sequence.
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