An investigation of the role of AINTEGUMENTA and AINTEGUMENTA-like genes in flower development

Flower development is a widely studied subject in the field of plant biology. Certain aspects of reproductive growth, namely, floral induction, the specification of floral meristem identity, and the determination of floral organ identity are relatively well understood. Much less is known, however, about the consequences of floral organ specification. For instance, how is organ patterning established so that a defined number and type of organ is found in each whorl? Once floral organs are specified, what factors are involved in the control of organ size and shape?; The Arabidopsis gene AINTEGUMENTA (ANT) is one such factor that plays an important role in the initiation and growth of floral organs. The consequences of both loss-of-function and ectopic expression of ANT have been well characterized. However, the molecular and genetic mechanisms underlying ANT function are less well understood. Over the past several years, we have attempted to discern some of these underlying mechanisms of ANT function. Although ANT's role as a transcription factor had previously been suggested based on aspects of its sequence, DNA binding by ANT had never been demonstrated. Our studies include the demonstration of DNA binding by ANT, as well as the determination of its DNA binding specificity. In addition, we have generated two steroid-inducible forms of ANT that will be used in future studies to identify downstream targets that it regulates.; We have also uncovered evidence for a genetic interaction between ANT and members of the YABBY gene family. This work will help provide additional clues as to the pathway(s) ANT may be working through in order to carry out its function. Finally, we have begun the initial characterization of members of the AINTEGUMENTA -LIKE (AIL) gene family. Members of this family show sequence homology to ANT. The analysis of these genes could provide additional insights into how ANT and its relatives carry out their functions in organ growth and development in Arabidopsis.