QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online February 18, 2004
doi: 10.1242/10.1242/dev.00949

This Article Summary Full Text Full Text (PDF) Supplemental Figures Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Related articles in Development Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Dinneny, J. R. Articles by Weigel, D. Search for Related Content PubMed PubMed Citation Articles by Dinneny, J. R. Articles by Weigel, D.

The role of JAGGED in shaping lateral organs

¹ Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
² Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
³ Department of Plant Sciences, The University of Arizona, Tucson, AZ 85721-0036, USA
⁴ Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
⁵ Department of Molecular Biology, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany

View larger version (48K): [in a new window]   Fig. 5. RT-PCR analysis of JAG and JGL expression in different tissues. (A) Expression in wild type. Numbers refer to PCR cycles. RNA was extracted from roots of seedlings grown vertically on MS agar plates; vegetative shoots of 2-week-old plants; mature rosette leaves; mature cauline leaves; inflorescence stems; 4-week-old inflorescence shoots including flowers up to stage 12; and stage 13 open flowers. (B) JAG expression in inflorescences of jag mutants. Amplification of TUBULIN was used as a control.

View larger version (113K): [in a new window]   Fig. 1. Phenotypes of jag-1 mutants. (A) Wild-type rosette leaf. (B) jag-1 rosette leaf. (C) Wild-type flower. (D) jag-1 flower. The sepals are shorter and narrower than those of wild type and the petals are short and narrow and do not reflect as much light as the white wild-type petals. (E) Close-up of wild-type sepal indicates small white region at the tip. (F) jag-1 sepal. Note jagged white tissue at tip (marked by a bracket). (G) Close-up of wild-type petal. (H) Three examples of jag-1 petals. Note that the distal white region (bracket) is reduced or absent in jag-1. (I,J) Scanning electron microscopy (SEM) of anthers. (I) Wild-type. (J) jag-1. Anthers are shorter and are spade shaped. (K-P) SEMs of petal tips. (K,N) Adaxial side of wild-type petal epidermis. The cells are uniformly conical with cuticular ridges. (L,O) jag-1 petal cells are not as uniform and have elongated cells interspersed, which have irregular cuticular ridges. These cells resemble epidermal cells near the base of wild-type petals, shown in M,P. Scale bars: 50 µm (I,J), 20 µm (K-M) and 4 µm (N-P).

View larger version (52K): [in a new window]   Fig. 2. HISTONE 4 expression during wild-type and jag-1 petal development. (A) Graph showing average number of H4-expressing cells in medial-longitudinal sections of petal primordia. Wild type (red, square), jag-1 (blue, circle). Error bars indicate 95% confidence intervals (2x standard error of the mean). (B) Medial-longitudinal section through petal primordia from stage 7 to 12. Note high frequency of H4-expressing cells in distal region. (C) H4 expression in petals of jag-1 mutants. Total number of petals examined for each stage range from 8 to 17 for wild type and 8 to 26 for jag-1. Scale bars: 50 µm (B,C stages 7-10) and 80 µm (B,C stages 11, 12).

View larger version (67K): [in a new window]   Fig. 3. Phenotypes of jag-5D mutants. (A-C) Inflorescences of wild-type (A), jag-5D heterozygous (B), and jag-5D homozygous plants (C). White arrow points to flower subtended by a bract, black arrow points to a bractless flower. (D) Examples of bract development on the inflorescence of jag-5D heterozygous mutants including filamentous, (top left), and large laminar bracts (bottom center). Note jagged edges and pointed tips of bracts, and lack of defined petioles. (E) SEM of stipules at the base of a bract of a jag-5D homozygous mutant (arrows). (F) Example of suppression of floral identity in a jag-5D homozygote. Arrow points to a leafy shoot. (G) Example of ectopic co-florescence in jag-5D heterozygote (arrow). (H) Wild-type rosette leaf with typical paddle shape. Bracket marks petiole. (I) In jag-5D mutants, blade tissue develops ectopically on petiole. (J) Ectopic blade tissue on the stem of shoots that develop in the axils of rosette leaves (bracket marks ectopic blade). (K) SEM of a wild-type inflorescence apex. (L) SEM of a jag-5D heterozygote. Arrowhead points to a bract primordium (br). Scale bar: 100 µm (E,K,L).

View larger version (123K): [in a new window]   Fig. 6. Expression of JAG and FIL, examined by in situ hybridization. (A-C, E-H) JAG expression in wild-type Columbia. (A) Vegetative shoot apex from a 2-week-old plant. JAG is expressed in incipient leaf primordia (ip) and older leaf primordia (lp), but absent from the shoot apical meristem (vm) and petiole regions (brackets). (B,C) Serial transverse sections of a vegetative shoot separated by 16 µm. JAG is expressed in the leaf blade and is strongest in the marginal regions (brackets) and excluded from the petiole. Asterisk marks same leaf in both sections. Strong JAG expression is also seen in stipules (sp). (D) FIL expression in wild-type Columbia inflorescence. Arrow indicates the cryptic bract (cb). Inflorescence meristem (im), floral meristem (fm). (E) JAG is expressed very early in the presumptive sepal (se) primordia of late-stage 2 flowers. JAG expression is not detected in floral or inflorescence meristems or the cryptic bract. (F) Stage 6 floral primordia show strong expression in initiating stamens (st), carpels (ca) and fading expression in sepals. (G) Transverse section of gynoecium. Floral stage indicated in lower left corner. During stage 8, JAG is expressed in the valves (v) and excluded from the replum (r). At stage 9, JAG expression diminishes in the valves but is maintained near the valve margins. (H) Expression of JAG during petal development from stage 8 to 11. JAG accumulates in the distal region of petals and disappears by stage 12. (I,J) JAG expression in jag-5D heterozygotes. (I) Note weak signal throughout the inflorescence, with higher levels of expression in the initiating bract (br) and inflorescence meristem. (J) Prolonged and ectopic expression in stamen filament (fi), and gynoecium including ovules (ov) in a stage 12 flower. (K) JAG is strongly expressed in the ectopic bracts of ap1 mutants. Scale bars: 100 µm (A-G, I, K), 50 µm (H), and 200 µm (J).

View larger version (79K): [in a new window]   Fig. 4. Molecular characterization of JAG. (A) Genomic structure. Small vertical arrows indicate borders of restriction fragment used for recapitulation (see B). Triangles mark T-DNA insertions in jag-1 and jag-4. (B) Inflorescence of an intermediate line that recapitulates the jag-5D phenotype. (C) Confocal image of epidermal cells from the pedicel of a floral primordium transformed with a construct in which a JAG:GFP fusion protein is expressed under control of the AP1 promoter. (D) Alignment of predicted amino-acid sequences of JAG, JGL, OsJAG and SUP. Periods indicate residues that are identical or similar in at least two sequences, and small asterisks indicate residues that are identical in all sequences. Beneath the zinc-finger domain, pink arrows indicate residues that determine DNA-binding specificity.

View larger version (102K): [in a new window]   Fig. 7. Phenotypes of jag-1 ap1-15 double mutants. (A) ap1-15 flower, with a medial bract (mb) indicated. (B) jag-1 ap1-15 flower, lacking all bracts. (C) ap1-15 inflorescence, with secondary flowers (2°) indicated. (D) jag-1 ap1-15 inflorescence; note that secondary flowers are unaffected. (E) SEM of ap1-15 inflorescence apex. In ap1-15 mutants, lateral bracts (lb) fail to grow, while medial bracts continue to grow. (F) SEM of jag-1 ap1-15 inflorescence apex. Both lateral and medial bracts fail to grow out.

View larger version (136K): [in a new window]   Fig. 8. Phenotypic effects of JAG expression under the control of the AP1 promoter. (A,E,F) Intermediate AP1::JAG lines usually form flowers with extended sepal-tubes sheathing the inner whorls. The junction between sepals and the pedicel is abnormal with sepaloid tissue running down the length of the pedicel (indicated by bracket in E). (F) SEM shows that the epidermis of the stalk of AP1::JAG flowers resembles that of wild-type sepals, shown in the inset. It differs from the wild-type pedicel epidermis shown in (G). (B,C,H) Strong AP1::JAG lines develop snake-like outgrowths in place of flowers. Only first-whorl organs initiate. (H) Amorphous tissue can sometimes be seen developing in the center of flower-like structures. (D) Weak AP1::JAG lines typically have sepals that are fused at the base (arrows). In place of petals and stamens, composite organs with petal and stamen identity form. (I) Expression of FIL in a stage 3 floral primordium of wild type. (J) In a strong AP1::JAG line, the FIL domain is expanded into the pedicel. Scale bars: 200 µm (C), 100µm (F,H) and 50 µm (G).