Biochemical characterization of Bombyx mori Dicer-2 that dices double-stranded RNAs into 20-nt small RNA.

We detected enzymatic activity that generates 20-nucleotide (nt) RNA from double-stranded RNAs (dsRNAs) in crude extracts prepared from various silkworm (Bombyx mori) organs. The result using knocked-down cultured cells indicated that this dicing activity originated from B. mori Dicer-2 (BmDcr2).

Structural features of T-DNA that induce transcriptional gene silencing during agroinfiltration.

() is used for the transient expression of foreign genes by the agroinfiltration method, but the introduction of foreign genes often induces transcriptional and/or post-transcriptional gene silencing (TGS and/or PTGS). In this study, we characterized the structural features of T-DNA that induce TGS during agroinfiltration. When cells harboring an empty T-DNA plasmid containing the cauliflower mosaic virus (CaMV) 35S promoter were infiltrated into the leaves of line 16c with a GFP gene over-expressed under the control of the same promoter, no small interfering RNAs (siRNAs) were derived from the GFP sequence.

The dicing activity of DCL3 and DCL4 is negatively affected by flavonoids.

The dicing activities of DCL3 and DCL4 are inhibited by accumulated metabolites in soybean leaves. Epicatechin and 7,4'-dihydroxyflavone inhibited Arabidopsis DCL3 and DCL4 in vitro. Flavonoids are major secondary metabolites in plants, and soybean (Glycine max L.

Disturbance of floral colour pattern by activation of an endogenous pararetrovirus, petunia vein clearing virus, in aged petunia plants.

White areas of star-type bicolour petals of petunia (Petunia hybrida) are caused by post-transcriptional gene silencing (PTGS) of the key enzyme of anthocyanin biosynthesis. We observed blotched flowers and a vein-clearing symptom in aged petunia plants. To determine the cause of blotched flowers, we focused on an endogenous pararetrovirus, petunia vein clearing virus (PVCV), because this virus may have a suppressor of PTGS (VSR).