First published online February 18, 2004
Development 131, 505e (2004)
© The Company of Biologists Limited
Don't stop cycling
Two papers describe a novel Arabidopsis gene with a crucial role
in the differentiation, shape and form of petals and leaves. On
p. 1101 and
p. 1111, both Dinneny
et al. and Ohno et al. have characterised JAGGED (JAG), the
loss of which causes the distal regions of petals and leaves to become
misshaped. JAG expression in organ primordia coincides with regions undergoing
active cell division, and in JAG mutants, cell-cycle activity
declines abnormally early. The authors suggest that JAG slows down the
cessation of cell division in distal regions of the organ primordia until
proper morphogenesis occurs, thereby suppressing premature differentiation.
Curiously, although JAG is not necessary for the initiation of organ
formation, its ectopic expression can induce tissue proliferation. Most
strikingly, JAG misexpression causes the formation of bracts - elongate
leaf-like organs located just below flowers - which are not normally produced
by Arabidopsis. Both groups speculate that the exclusion of JAG from
the bract-forming region may be the cause of bractless flowers in
Arabidopsis and other Brassicaceae.
Related articles in Development:
- The role of JAGGED in shaping lateral organs
- José R. Dinneny, Ramin Yadegari, Robert L. Fischer, Martin F. Yanofsky, and Detlef Weigel
Development 2004 131: 1101-1110.
[Abstract]
[Full Text]
- The Arabidopsis JAGGED gene encodes a zinc finger protein that promotes leaf tissue development
- Carolyn K. Ohno, G. Venugopala Reddy, Marcus G. B. Heisler, and Elliot M. Meyerowitz
Development 2004 131: 1111-1122.
[Abstract]
[Full Text]
