Cell-Cell Signaling and Movement by the Floral Transcription Factors LEAFY and APETALA1

[Rcjohnsen]

Botany   Sci   Aug 4, 00

Cell-Cell Signaling and Movement by the Floral Transcription Factors LEAFY and
APETALA1 

Allen Sessions,1, 2* Martin F. Yanofsky,1 Detlef Weigel2  
LEAFY (LFY) and APETALA1 (AP1) encode unrelated transcription factors that
activate overlapping sets of homeotic genes in Arabidopsis flowers. Sector
analysis and targeted expression in transgenic plants were used to study
whether LFY and AP1 can participate in cell-cell signaling between and within
different layers of the floral meristem. LFY signaled equally well from all
layers and had substantial long-range action within layers. Nonautonomous
action of LFY was accompanied by movement of the protein to adjacent cells,
where it directly activated homeotic target genes. In contrast, AP1 had only
limited nonautonomous effects, apparently mediated by downstream genes because
activation of early target genes by AP1 was cell-autonomous. 
1 Department of Biology, University of California, San Diego, La Jolla, CA
92093, USA. 
2 Plant Biology Laboratory, Salk Institute for Biological Studies, 10010 North
Torrey Pines Road, La Jolla, CA 92037, USA. 
*   Present address: Novartis Agricultural Discovery Institute, 3115 Merryfield
Row, San Diego, CA 92121, USA.  

   To whom correspondence should be addressed. E-mail: marty at ucsd.edu,
weigel at salk.edu 


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