First published online February 18, 2004
doi: 10.1242/10.1242/dev.00949
Development 131, 1101-1110 (2004)
Published by The Company of Biologists 2004
The role of JAGGED in shaping lateral organs
José R. Dinneny1,2,
Ramin Yadegari3,
Robert L. Fischer4,
Martin F. Yanofsky2 and
Detlef Weigel1,5,*
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
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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.
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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).
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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).
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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).
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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).
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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.
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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.
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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).
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