Project name: Nicotiana tabacum

Description: Sense transgene-induced post-transcriptional gene silencing (S-PTGS) is a type of RNA silencing in which ARGONAUTE1 directs small interfering RNA (siRNA)-mediated cleavage of 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 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. Although transcription proceeded to the last exon of the endogenous NtFAD3 gene, intron-containing NtFAD3 transcripts accumulated in the nucleus of the S-PTGS plants. Several intron-containing NtFAD3 transcripts harboring most exon sequences were generated when an endogenous silencing suppressor gene, rgs-CaM, was overexpressed in the S-PTGS plants. These intron-containing NtFAD3 splice variants were generated in the presence of NtFAD3 siRNAs that are homologous to the nucleotide sequences of these splice variants. The present results indicate that the inhibition of endo-NtFAD3 gene expression is primarily directed via the alteration of splicing, and not by cytoplasmic slicer activity. Our results suggest that the transgene and intron-containing endogenous counterpart genes are differentially suppressed in S-PTGS plants.

Data type: Other

Sample scope: Other

Release date: 2014-05-12

Last updated: 2013-11-12