<i>essp5</i> Results in Ectopic Expression of a Seed Marker Gene and Is Allelic to <i>ARGONAUTE1</i>.

<p>(A and B) Comparison of <i>essp5</i> with wild type (wt) plants at two weeks. (C and D) GUS expression of the <i>essp5</i> mutant (C) and wild type (<i>wt</i>, <i>βCG:GUS</i>) grown on agar at two weeks. Scale bars, 2 mm in (C) and 5 mm in (D). (E) Alignment of partial amino acid sequences (residues 707 to 755) of PIWI domains in AGO proteins from Arabidopsis (At), Rice (Os), Pea (Ps), Tobacco (Nb), Drosophila (Dm), Brassica (Bn). The <i>essp5</i> mutation site (L740) is in orange. The asterisks indicate absolutely conserved residues, colons indicate high similarity, and dots indicate low similarity. (F) Structure of the <i>AGO1</i> gene showing the location of the <i>essp5</i> mutation and the T-DNA insertion sites of other <i>ago1</i> alleles. Boxes and lines represent exons and introns, respectively. The colored boxes represent the conserved protein domains: light blue (PAZ), magenta (MID), and blue (PIWI). (G–J) GUS expression in four T-DNA insertion alleles of <i>AGO1</i>. Shown here is a representative F₂ progeny from each of the crosses of the corresponding T-DNA allele with the <i>βCG:GUS</i> line. Scale bar, 500 µm.