title: Gene silencing induced by hairpin or inverted repeated sense transgenes varies among promoters and cell types.
abstract: *In transgenic calli and different tissues of Arabidopsis thaliana plants, the in trans silencing capacity of a 35S-beta-glucuronidase (GUS) hairpin RNA construct was investigated on a target GUS gene, under the control of the 35S, a WRKY or several cell cycle-specific promoters. *GUS histochemical staining patterns were analyzed in all tissues of the parental lines and supertransformants harboring the hairpin construct. Quantitative GUS activity measurements determined GUS suppression by a 35S-GUS hairpin or inverted repeated GUS transgenes in leaves and calli. *In some supertransformants, GUS-based staining disappeared in all tissues, including calli. In most supertransformants, however, a significant reduction was found in mature roots and leaves, but residual GUS activity was observed in the root tips, young leaves and calli. In leaves of most hairpin RNA supertransformants, the GUS activity was reduced by c. 1000-fold or more, but, in derived calli, generally by less than 200-fold. The silencing efficiency of inverted repeated sense transgenes was similar to that of a hairpin RNA construct in leaves, but weaker in calli. *These results imply that the tissue type, nature of the silencing inducer locus and the differential expression of the targeted gene codetermine the silencing efficiency.
authors.affiliation: Department of Plant Systems Biology, VIB, Technologiepark 927, Gent, Belgium.
authors.forename: Gordana
authors.initials: G
authors.lastname: Marjanac
authors.forename: Mansour
authors.initials: M
authors.lastname: Karimi
authors.forename: Mirande
authors.initials: M
authors.lastname: Naudts
authors.forename: Tom
authors.initials: T
authors.lastname: Beeckman
authors.forename: Anna
authors.initials: A
authors.lastname: Depicker
authors.forename: Sylvie
authors.initials: S
authors.lastname: De Buck
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D020868:Gene Silencing; D005966:Glucuronidase / Q000235:genetics* / Q000378:metabolism; D055029:Inverted Repeat Sequences; D018514:Plant Structures / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D012313:RNA; D019076:Transgenes
chemical_list: D029681:Arabidopsis Proteins; D012313:RNA; D005966:Glucuronidase