Both sense and antisense RNAs are targets for the sense transgene-induced posttranscriptional silencing mechanism.
Two stable transgenic tobacco lines were obtained as segregants from a primary transformant. Plants homozygous for a T-DNA inverted repeat locus (HOlo1) showed posttranscriptional gene silencing (PTGS) of the neomycin phosphotransferase II (nptII) transgenes, whereas HOlo2 plants, homozygous for a single T-DNA insert, expressed the nptII genes normally. Transient expression of nptII genes newly introduced into leaves of both the HOlo2 and nptII-silenced HOlo1 plants was downregulated only in the silenced background. Different chimeric beta-glucuronidase (gus) genes with parts of the nptII transgene inserted in sense or antisense orientation into the 3'-untranslated region, which encoded transcripts that had homology or complementarity to nptII transcripts. showed reduced transient expression specifically in nptII-silenced tissue. Therefore, we conclude that RNAs of both polarities are targets for PTGS-induced RNA degradation, which supports the notion that double-stranded RNA acts as an inducing signal for silencing.
Van Houdt
H
H
Departement Plantengenetica, Vlaams Interuniversitair Institute voor Biotechnologie, Universiteit Gent, Belgium.
Van Montagu
M
M
Depicker
A
A
D016960:Agrobacterium tumefaciens / Q000235:genetics; D015870:Gene Expression; D020868:Gene Silencing; D005966:Glucuronidase / Q000235:genetics; D019868:Kanamycin Kinase / Q000235:genetics*; D018515:Plant Leaves / Q000378:metabolism; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D012323:RNA Processing, Post-Transcriptional; D016372:RNA, Antisense; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D014026:Nicotiana / Q000235:genetics*; D014170:Transformation, Genetic; D019076:Transgenes
D016372:RNA, Antisense; D011993:Recombinant Fusion Proteins; D019868:Kanamycin Kinase; D005966:Glucuronidase