Role of the F-Box Protein UFO in Flower Development

The Salk Institute For Biological Studies, La Jolla CA

Investigators

Abstract

0078273 Weigel Flowers give rise to fruits and seeds, which include all cereals, and thereby provide the majority of calories consumed by humans. Understanding the mechanisms of flower development is therefore interesting both from a scientific and from an agronomic point of view. Early flower development is regulated by a cascade of regulatory genes that include flowering-time genes, meristem-identity genes and homeotic organ-identity genes. Most of these genes encode transcription factors, and some progress has been made in understanding the genetic and molecular interactions between these groups of genes. However, less is known about the downstream effectors of floral homeotic genes. Dr. Weigel is studying the UFO gene, which regulates several aspects of flower development in Arabidopsis. In contrast to many other floral control genes, UFO does not encode a transcription factor. Instead, UFO encodes an F-box protein that is likely to affect the stability of other regulatory proteins. Dr. Weigel has shown that UFO acts as an F-box protein in vivo, and that it functions downstream of the homeotic gene AP1 in the formation of petals. He now proposes genetic, molecular and biochemical approaches (1) to determine whether UFO function is required in all cell layers to promote petal growth; (2) to determine how UFO expression in petals is controlled, with emphasis on the role of the homeotic gene AP1 in this process; (3) to identify proteins that interact with UFO in vivo and mediate its effects; and (4) to identify new genes that act with UFO in petal formation. The proposed work will advance our understanding of the mechanisms by which F-box proteins affect plant growth and development. Furthering our knowledge of plant development in turn will enhance our ability to improve growth and yield of crop plants.