title: RNA silencing in plants by the expression of siRNA duplexes.
abstract: In animal cells, stable RNA silencing can be achieved by vector-based small interfering RNA (siRNA) expression system, in which Pol III RNA gene promoters are used to drive the expression of short hairpin RNA, however, this has not been demonstrated in plants. Whether Pol III RNA gene promoter is capable of driving siRNA expression in plants is unknown. Here, we report that RNA silencing was achieved in plants through stable expression of short hairpin RNA, which was driven by Pol III RNA gene promoters. Using glucuronidase (GUS) transformed tobacco as a model system, the results demonstrated that 21 nt RNA duplexes, targeting at different sites of GUS gene, were stably expressed under the control of either human H1 or Arabidopsis 7SL RNA gene promoter, and GUS gene was silenced in 80% of siRNA transgenics. The severity of silencing was correlated with the abundance of siRNA expression but independent of the target sites and uridine residue structures in siRNA hairpin transcripts. Thus, the specific expression of siRNA provides a new system for the study of siRNA silencing pathways and functional genomics in plants. Moreover, the effectiveness of the human H1 promoter in a plant background suggested a conserved mechanism underlying Pol III complex functionality.
authors.affiliation: Forest Biotechnology Group, Department of Forestry, North Carolina State University, Raleigh, NC 27695, USA. slu@ncsu.edu
authors.forename: Shanfa
authors.initials: S
authors.lastname: Lu
authors.forename: Rui
authors.initials: R
authors.lastname: Shi
authors.forename: Cheng-Chung
authors.initials: CC
authors.lastname: Tsao
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Yi
authors.forename: Laigeng
authors.initials: L
authors.lastname: Li
authors.forename: Vincent L
authors.initials: VL
authors.lastname: Chiang
mesh_terms: D018506:Gene Expression Regulation, Plant; D005822:Genetic Vectors; D005966:Glucuronidase / Q000032:analysis / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012313:RNA / Q000235:genetics; D034622:RNA Interference; D020733:RNA, Small Cytoplasmic / Q000235:genetics; D034741:RNA, Small Interfering / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D018271:Signal Recognition Particle / Q000235:genetics; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism
chemical_list: C115990:7SL RNA; D020733:RNA, Small Cytoplasmic; D034741:RNA, Small Interfering; D018271:Signal Recognition Particle; D012313:RNA; D005966:Glucuronidase