THE PLANT CELL, Vol 6, Issue 9 1211-1225, Copyright © 1994 by American Society of Plant Biologists
Control of Arabidopsis Flower and Seed Development by the Homeotic Gene APETALA2
K. D. Jofuku, BGWd. Boer, M. V. Montagu and J. K. Okamuro
Sinsheimer Laboratories, Department of Biology, University of California, Santa Cruz, California 95064
APETALA2 (AP2) plays a central role in the establishment of the floral
meristem, the specification of floral organ identity, and the regulation of
floral homeotic gene expression in Arabidopsis. We show here that in
addition to its functions during flower development, AP2 activity is also
required during seed development. We isolated the AP2 gene and found that
it encodes a putative nuclear protein that is distinguished by an essential
68-amino acid repeated motif, the AP2 domain. Consistent with its genetic
functions, we determined that AP2 is expressed at the RNA level in all four
types of floral organs-sepals, petals, stamens, and carpels-and in
developing ovules. Thus, AP2 gene transcription does not appear to be
spatially restricted by the floral homeotic gene AGAMOUS as predicted by
previous studies. We also found that AP2 is expressed at the RNA level in
the inflorescence meristem and in nonfloral organs, including leaf and
stem. Taken together, our results suggest that AP2 represents a new class
of plant regulatory proteins that may play a general role in the control of
Arabidopsis development.
