Article Figures & Data
Figures
- Figure 1.
Pleiotropic Phenotype of the Arabidopsis hyl1 Mutant.
(A) Wild-type (left) and hyl1 mutant (right) seedlings grown on Murashige and Skoog (MS) plates.
(B) Flowers of the wild-type (left) and hyl1 mutant (right) plants.
(C) Rosette leaves from three-week-old wild-type (left) and hyl1 mutant (right two) plants.
(D) Mature wild-type and hyl1 plants.
(E) Hypocotyls of wild-type (left) and hyl1 (right) plants.
- Figure 2.
Gravitropic Responses of Wild-Type and hyl1 Mutant Seedlings.
Seedlings growing on MS medium or MS containing 0.05 μM TIBA were rotated 90° at time 0. Seedlings were aligned on the plates so that all the root tips were perpendicular to the bottom line of the Petri dish. The angle of curvature of the growing root tips was measured at 1- to 2-hr intervals. Filled diamonds, wild-type seedlings on MS medium; filled squares, wild-type seedlings on MS medium + 0.05 μM TIBA; open triangles, hyl1 seedlings on MS medium; open circles, hyl1 seedlings on MS medium + 0.05 mM TIBA.
- Figure 3.
Ds Insertion Site in the HYL1 Gene.
(A) The exons of the HYL1 gene are numbered I to III. The Ds element insertion site is in the second exon.
(B) The sequence around the Ds insertion site is shown for the wild type, the hyl1 insertion mutant, a wild-type revertant, and the hyl1* mutant allele created by Ds excision. The underlined 8-bp sequence is the target site duplication. The 6- and 7-bp transposon footprints are indicated in italics.
- Figure 4.
Effects of Exogenous ABA on Wild-Type (open squares) and hyl1 (open diamonds) Mutant Arabidopsis.
(A) hyl1 and wild-type seeds were placed on filter paper saturated with either water (left) or 0.5 μM ABA (right), incubated at 4°C for 48 hr, and then transferred to room temperature for germination.
(B) Relative root elongation rates of wild-type Nossen (No-0) and hyl1 mutant 10-day-old seedlings. Mean values for 100% root elongation were determined on MS medium containing no ABA. Error bars indicate sd.
(C) RNA gel blot analysis of ABA-induced mRNAs in hyl1 and wild-type plants. Arabidopsis plants were grown on MS plates for 2 weeks, then transferred into 0.1 × MS medium containing 50 μM ABA. Ten micrograms of total cellular RNA isolated from the wild-type and hyl1 seedlings at the indicated times after treatment with ABA was used in each lane. Probes are indicated for each panel.
- Figure 5.
Growth of hyl1 and Wild-Type Seedlings on Medium Containing Auxin and Auxin Transport Inhibitors.
hyl1 (open diamonds) and wild-type (open squares) seedlings were grown on MS medium supplemented with different concentrations of chemicals; root length was measured 10 days after germination. Root growth is expressed relative to growth on unsupplemented MS medium. Each point represents a test of 20 seedlings.
(A) IAA.
(B) 2,4-D.
(C) TIBA.
(D) NPA.
Error bars indicate sd.
- Figure 6.
Responses of hyl1 and Wild-Type Seedlings to Exogenous Cytokinin.
(A) Wild-type (left) and hyl1 (right) seedlings grown on MS medium.
(B) Wild-type (left) and hyl1 (right) seedlings grown on MS medium containing 1 μM BA.
(C) Wild-type (left) and hyl1 (right) seedlings grown in the dark for 3 days on MS medium with or without 0.5 μM BA.
(D) The fresh weight of wild-type (open squares) and hyl1 (open diamonds) mutant seedlings at 14 days after germination on MS medium containing the indicated concentrations of BA. Shown is the dose–response curve for one representative experiment of three performed. Error bars indicate sd.
- Figure 7.
Motifs in the HYL1 Protein Sequence.
(A) Deduced amino acid sequence of the HYL1 gene. The two putative dsRNA binding motifs are shown in white letters on a black background, the putative nuclear localization motif is indicated in italics, and the six consecutive C-terminal repeats are underlined.
(B) Alignment of the dsRNA binding motifs of HYL1 protein with those of other proteins with dsRNA binding domains. The conserved regions are in white letters on a black background. Dashes were introduced to optimize alignments.
(C) Alignment of the putative bipartite nuclear localization sequence of HYL1 with similar motifs in other proteins. The basic residues at the ends of the motif are shown in white letters on a black background.
- Figure 8.
Expression of the HYL1 Gene.
(A) RNA was isolated from rosette leaves (RL), cauline leaves (CL), inflorescent stems (S), roots (R), and flowers (F); fractionated on a 1.2% formaldehyde–agarose gel; blotted onto nitrocellulose; and probed with a full-length HYL1 cDNA probe.
(B) RNA was isolated from seedlings 0, 2, 4, 8, or 24 hr after exposure to 50 μM ABA (left) or after 1.5-hr exposure to different concentrations of 2,4-D, ranging from 0.1 to 100 μM. RNA was fractionated and analyzed as described in (A).
- Figure 9.
Subcellular Localization of an HYL1–GUS Fusion Protein.
(A) Structure of the GUS reporter construct.
(B) Structure of the HYL1 cDNA–GUS fusion construct.
The constructs were introduced into onion epidermal cells by particle bombardment. The cells were stained for GUS activity after 20 hr of incubation at room temperature. The two cells shown are representative of the results obtained in two independent experiments.
- Figure 10.
Native Gel Mobility Shift Analysis of HYL1 Protein Binding to Nucleic Acids.
An RNA duplex of ∼100 bp was prepared by end-labeling hybridized T7 and T3 transcripts of the pBluescript II KS plasmid. A PCR fragment that includes both T7 and T3 promoters and intervening sequences of the same plasmid was used as dsDNA substrate. ssDNA was produced by denaturing and gel-purifying the same dsDNA fragment. A T7 transcript of the plasmid was used for ssRNA. Approximately the same amount of each test molecule (10 ng) was used for each experiment; the amount of the His-tagged HYL1 protein fragment added is indicated.
